6d9e515905
Documentation is synchronized to match external, to ease updating. blacklist is replaced with ignorelist or ignore depending on context. Test: none Change-Id: I6db7ad321684759e3c5ac1f66f940b6e8a5709a0
1444 lines
55 KiB
C++
1444 lines
55 KiB
C++
/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "llkd.h"
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#include <ctype.h>
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#include <dirent.h> // opendir() and readdir()
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#include <errno.h>
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#include <fcntl.h>
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#include <pthread.h>
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#include <pwd.h> // getpwuid()
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#include <signal.h>
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#include <stdint.h>
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#include <string.h>
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#include <sys/cdefs.h> // ___STRING, __predict_true() and _predict_false()
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#include <sys/mman.h> // mlockall()
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#include <sys/prctl.h>
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#include <sys/stat.h> // lstat()
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#include <sys/syscall.h> // __NR_getdents64
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#include <sys/sysinfo.h> // get_nprocs_conf()
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#include <sys/types.h>
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#include <time.h>
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#include <unistd.h>
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#include <chrono>
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#include <ios>
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#include <sstream>
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#include <string>
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#include <unordered_map>
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#include <unordered_set>
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#include <vector>
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#include <android-base/file.h>
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#include <android-base/logging.h>
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#include <android-base/parseint.h>
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#include <android-base/properties.h>
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#include <android-base/strings.h>
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#include <cutils/android_get_control_file.h>
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#include <log/log_main.h>
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
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#define TASK_COMM_LEN 16 // internal kernel, not uapi, from .../linux/include/linux/sched.h
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using namespace std::chrono_literals;
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using namespace std::chrono;
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using namespace std::literals;
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namespace {
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constexpr pid_t kernelPid = 0;
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constexpr pid_t initPid = 1;
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constexpr pid_t kthreaddPid = 2;
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constexpr char procdir[] = "/proc/";
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// Configuration
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milliseconds llkUpdate; // last check ms signature
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milliseconds llkCycle; // ms to next thread check
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bool llkEnable = LLK_ENABLE_DEFAULT; // llk daemon enabled
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bool llkRunning = false; // thread is running
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bool llkMlockall = LLK_MLOCKALL_DEFAULT; // run mlocked
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bool llkTestWithKill = LLK_KILLTEST_DEFAULT; // issue test kills
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milliseconds llkTimeoutMs = LLK_TIMEOUT_MS_DEFAULT; // default timeout
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enum { // enum of state indexes
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llkStateD, // Persistent 'D' state
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llkStateZ, // Persistent 'Z' state
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#ifdef __PTRACE_ENABLED__ // Extra privileged states
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llkStateStack, // stack signature
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#endif // End of extra privilege
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llkNumStates, // Maxumum number of states
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}; // state indexes
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milliseconds llkStateTimeoutMs[llkNumStates]; // timeout override for each detection state
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milliseconds llkCheckMs; // checking interval to inspect any
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// persistent live-locked states
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bool llkLowRam; // ro.config.low_ram
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bool llkEnableSysrqT = LLK_ENABLE_SYSRQ_T_DEFAULT; // sysrq stack trace dump
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bool khtEnable = LLK_ENABLE_DEFAULT; // [khungtaskd] panic
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// [khungtaskd] should have a timeout beyond the granularity of llkTimeoutMs.
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// Provides a wide angle of margin b/c khtTimeout is also its granularity.
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seconds khtTimeout = duration_cast<seconds>(llkTimeoutMs * (1 + LLK_CHECKS_PER_TIMEOUT_DEFAULT) /
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LLK_CHECKS_PER_TIMEOUT_DEFAULT);
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#ifdef __PTRACE_ENABLED__
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// list of stack symbols to search for persistence.
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std::unordered_set<std::string> llkCheckStackSymbols;
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#endif
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// Ignorelist variables, initialized with comma separated lists of high false
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// positive and/or dangerous references, e.g. without self restart, for pid,
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// ppid, name and uid:
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// list of pids, or tids or names to skip. kernel pid (0), init pid (1),
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// [kthreadd] pid (2), ourselves, "init", "[kthreadd]", "lmkd", "llkd" or
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// combinations of watchdogd in kernel and user space.
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std::unordered_set<std::string> llkIgnorelistProcess;
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// list of parent pids, comm or cmdline names to skip. default:
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// kernel pid (0), [kthreadd] (2), or ourselves, enforced and implied
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std::unordered_set<std::string> llkIgnorelistParent;
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// list of parent and target processes to skip. default:
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// adbd *and* [setsid]
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std::unordered_map<std::string, std::unordered_set<std::string>> llkIgnorelistParentAndChild;
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// list of uids, and uid names, to skip, default nothing
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std::unordered_set<std::string> llkIgnorelistUid;
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#ifdef __PTRACE_ENABLED__
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// list of names to skip stack checking. "init", "lmkd", "llkd", "keystore" or
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// "logd" (if not userdebug).
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std::unordered_set<std::string> llkIgnorelistStack;
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#endif
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class dir {
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public:
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enum level { proc, task, numLevels };
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private:
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int fd;
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size_t available_bytes;
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dirent* next;
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// each directory level picked to be just north of 4K in size
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static constexpr size_t buffEntries = 15;
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static dirent buff[numLevels][buffEntries];
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bool fill(enum level index) {
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if (index >= numLevels) return false;
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if (available_bytes != 0) return true;
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if (__predict_false(fd < 0)) return false;
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// getdents64 has no libc wrapper
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auto rc = TEMP_FAILURE_RETRY(syscall(__NR_getdents64, fd, buff[index], sizeof(buff[0]), 0));
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if (rc <= 0) return false;
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available_bytes = rc;
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next = buff[index];
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return true;
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}
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public:
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dir() : fd(-1), available_bytes(0), next(nullptr) {}
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explicit dir(const char* directory)
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: fd(__predict_true(directory != nullptr)
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? ::open(directory, O_CLOEXEC | O_DIRECTORY | O_RDONLY)
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: -1),
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available_bytes(0),
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next(nullptr) {}
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explicit dir(const std::string&& directory)
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: fd(::open(directory.c_str(), O_CLOEXEC | O_DIRECTORY | O_RDONLY)),
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available_bytes(0),
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next(nullptr) {}
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explicit dir(const std::string& directory)
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: fd(::open(directory.c_str(), O_CLOEXEC | O_DIRECTORY | O_RDONLY)),
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available_bytes(0),
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next(nullptr) {}
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// Don't need any copy or move constructors.
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explicit dir(const dir& c) = delete;
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explicit dir(dir& c) = delete;
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explicit dir(dir&& c) = delete;
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~dir() {
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if (fd >= 0) {
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::close(fd);
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}
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}
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operator bool() const { return fd >= 0; }
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void reset(void) {
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if (fd >= 0) {
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::close(fd);
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fd = -1;
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available_bytes = 0;
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next = nullptr;
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}
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}
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dir& reset(const char* directory) {
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reset();
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// available_bytes will _always_ be zero here as its value is
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// intimately tied to fd < 0 or not.
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fd = ::open(directory, O_CLOEXEC | O_DIRECTORY | O_RDONLY);
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return *this;
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}
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void rewind(void) {
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if (fd >= 0) {
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::lseek(fd, off_t(0), SEEK_SET);
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available_bytes = 0;
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next = nullptr;
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}
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}
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dirent* read(enum level index = proc, dirent* def = nullptr) {
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if (!fill(index)) return def;
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auto ret = next;
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available_bytes -= next->d_reclen;
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next = reinterpret_cast<dirent*>(reinterpret_cast<char*>(next) + next->d_reclen);
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return ret;
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}
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} llkTopDirectory;
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dirent dir::buff[dir::numLevels][dir::buffEntries];
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// helper functions
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bool llkIsMissingExeLink(pid_t tid) {
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char c;
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// CAP_SYS_PTRACE is required to prevent ret == -1, but ENOENT is signal
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auto ret = ::readlink((procdir + std::to_string(tid) + "/exe").c_str(), &c, sizeof(c));
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return (ret == -1) && (errno == ENOENT);
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}
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// Common routine where caller accepts empty content as error/passthrough.
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// Reduces the churn of reporting read errors in the callers.
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std::string ReadFile(std::string&& path) {
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std::string content;
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if (!android::base::ReadFileToString(path, &content)) {
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PLOG(DEBUG) << "Read " << path << " failed";
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content = "";
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}
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return content;
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}
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std::string llkProcGetName(pid_t tid, const char* node = "/cmdline") {
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std::string content = ReadFile(procdir + std::to_string(tid) + node);
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static constexpr char needles[] = " \t\r\n"; // including trailing nul
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auto pos = content.find_first_of(needles, 0, sizeof(needles));
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if (pos != std::string::npos) {
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content.erase(pos);
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}
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return content;
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}
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uid_t llkProcGetUid(pid_t tid) {
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// Get the process' uid. The following read from /status is admittedly
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// racy, prone to corruption due to shape-changes. The consequences are
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// not catastrophic as we sample a few times before taking action.
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//
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// If /loginuid worked on reliably, or on Android (all tasks report -1)...
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// Android lmkd causes /cgroup to contain memory:/<dom>/uid_<uid>/pid_<pid>
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// which is tighter, but also not reliable.
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std::string content = ReadFile(procdir + std::to_string(tid) + "/status");
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static constexpr char Uid[] = "\nUid:";
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auto pos = content.find(Uid);
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if (pos == std::string::npos) {
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return -1;
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}
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pos += ::strlen(Uid);
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while ((pos < content.size()) && ::isblank(content[pos])) {
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++pos;
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}
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content.erase(0, pos);
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for (pos = 0; (pos < content.size()) && ::isdigit(content[pos]); ++pos) {
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;
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}
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// Content of form 'Uid: 0 0 0 0', newline is error
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if ((pos >= content.size()) || !::isblank(content[pos])) {
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return -1;
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}
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content.erase(pos);
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uid_t ret;
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if (!android::base::ParseUint(content, &ret, uid_t(0))) {
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return -1;
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}
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return ret;
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}
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struct proc {
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pid_t tid; // monitored thread id (in Z or D state).
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nanoseconds schedUpdate; // /proc/<tid>/sched "se.avg.lastUpdateTime",
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uint64_t nrSwitches; // /proc/<tid>/sched "nr_switches" for
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// refined ABA problem detection, determine
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// forward scheduling progress.
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milliseconds update; // llkUpdate millisecond signature of last.
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milliseconds count; // duration in state.
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#ifdef __PTRACE_ENABLED__ // Privileged state checking
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milliseconds count_stack; // duration where stack is stagnant.
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#endif // End privilege
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pid_t pid; // /proc/<pid> before iterating through
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// /proc/<pid>/task/<tid> for threads.
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pid_t ppid; // /proc/<tid>/stat field 4 parent pid.
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uid_t uid; // /proc/<tid>/status Uid: field.
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unsigned time; // sum of /proc/<tid>/stat field 14 utime &
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// 15 stime for coarse ABA problem detection.
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std::string cmdline; // cached /cmdline content
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char state; // /proc/<tid>/stat field 3: Z or D
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// (others we do not monitor: S, R, T or ?)
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#ifdef __PTRACE_ENABLED__ // Privileged state checking
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char stack; // index in llkCheckStackSymbols for matches
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#endif // and with maximum index PROP_VALUE_MAX/2.
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char comm[TASK_COMM_LEN + 3]; // space for adding '[' and ']'
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bool exeMissingValid; // exeMissing has been cached
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bool cmdlineValid; // cmdline has been cached
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bool updated; // cleared before monitoring pass.
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bool killed; // sent a kill to this thread, next panic...
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bool frozen; // process is in frozen cgroup.
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void setComm(const char* _comm) { strncpy(comm + 1, _comm, sizeof(comm) - 2); }
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void setFrozen(bool _frozen) { frozen = _frozen; }
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proc(pid_t tid, pid_t pid, pid_t ppid, const char* _comm, int time, char state, bool frozen)
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: tid(tid),
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schedUpdate(0),
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nrSwitches(0),
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update(llkUpdate),
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count(0ms),
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#ifdef __PTRACE_ENABLED__
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count_stack(0ms),
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#endif
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pid(pid),
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ppid(ppid),
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uid(-1),
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time(time),
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state(state),
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#ifdef __PTRACE_ENABLED__
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stack(-1),
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#endif
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exeMissingValid(false),
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cmdlineValid(false),
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updated(true),
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killed(!llkTestWithKill),
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frozen(frozen) {
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memset(comm, '\0', sizeof(comm));
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setComm(_comm);
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}
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const char* getComm(void) {
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if (comm[1] == '\0') { // comm Valid?
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strncpy(comm + 1, llkProcGetName(tid, "/comm").c_str(), sizeof(comm) - 2);
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}
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if (!exeMissingValid) {
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if (llkIsMissingExeLink(tid)) {
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comm[0] = '[';
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}
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exeMissingValid = true;
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}
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size_t len = strlen(comm + 1);
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if (__predict_true(len < (sizeof(comm) - 1))) {
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if (comm[0] == '[') {
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if ((comm[len] != ']') && __predict_true(len < (sizeof(comm) - 2))) {
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comm[++len] = ']';
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comm[++len] = '\0';
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}
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} else {
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if (comm[len] == ']') {
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comm[len] = '\0';
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}
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}
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}
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return &comm[comm[0] != '['];
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}
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const char* getCmdline(void) {
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if (!cmdlineValid) {
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cmdline = llkProcGetName(tid);
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cmdlineValid = true;
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}
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return cmdline.c_str();
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}
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uid_t getUid(void) {
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if (uid <= 0) { // Churn on root user, because most likely to setuid()
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uid = llkProcGetUid(tid);
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}
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return uid;
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}
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bool isFrozen() { return frozen; }
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void reset(void) { // reset cache, if we detected pid rollover
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uid = -1;
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state = '?';
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#ifdef __PTRACE_ENABLED__
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count_stack = 0ms;
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stack = -1;
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#endif
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cmdline = "";
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comm[0] = '\0';
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exeMissingValid = false;
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cmdlineValid = false;
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}
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};
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std::unordered_map<pid_t, proc> tids;
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// Check range and setup defaults, in order of propagation:
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// llkTimeoutMs
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// llkCheckMs
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// ...
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// KISS to keep it all self-contained, and called multiple times as parameters
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// are interpreted so that defaults, llkCheckMs and llkCycle make sense.
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void llkValidate() {
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if (llkTimeoutMs == 0ms) {
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llkTimeoutMs = LLK_TIMEOUT_MS_DEFAULT;
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}
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llkTimeoutMs = std::max(llkTimeoutMs, LLK_TIMEOUT_MS_MINIMUM);
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if (llkCheckMs == 0ms) {
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llkCheckMs = llkTimeoutMs / LLK_CHECKS_PER_TIMEOUT_DEFAULT;
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}
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llkCheckMs = std::min(llkCheckMs, llkTimeoutMs);
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for (size_t state = 0; state < ARRAY_SIZE(llkStateTimeoutMs); ++state) {
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if (llkStateTimeoutMs[state] == 0ms) {
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llkStateTimeoutMs[state] = llkTimeoutMs;
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}
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llkStateTimeoutMs[state] =
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std::min(std::max(llkStateTimeoutMs[state], LLK_TIMEOUT_MS_MINIMUM), llkTimeoutMs);
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llkCheckMs = std::min(llkCheckMs, llkStateTimeoutMs[state]);
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}
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llkCheckMs = std::max(llkCheckMs, LLK_CHECK_MS_MINIMUM);
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if (llkCycle == 0ms) {
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llkCycle = llkCheckMs;
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}
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llkCycle = std::min(llkCycle, llkCheckMs);
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}
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milliseconds llkGetTimespecDiffMs(timespec* from, timespec* to) {
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return duration_cast<milliseconds>(seconds(to->tv_sec - from->tv_sec)) +
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duration_cast<milliseconds>(nanoseconds(to->tv_nsec - from->tv_nsec));
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}
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std::string llkProcGetName(pid_t tid, const char* comm, const char* cmdline) {
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if ((cmdline != nullptr) && (*cmdline != '\0')) {
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return cmdline;
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}
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if ((comm != nullptr) && (*comm != '\0')) {
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return comm;
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}
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// UNLIKELY! Here because killed before we kill it?
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// Assume change is afoot, do not call llkTidAlloc
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// cmdline ?
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std::string content = llkProcGetName(tid);
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if (content.size() != 0) {
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return content;
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}
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// Comm instead?
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content = llkProcGetName(tid, "/comm");
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if (llkIsMissingExeLink(tid) && (content.size() != 0)) {
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return '[' + content + ']';
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}
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return content;
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}
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int llkKillOneProcess(pid_t pid, char state, pid_t tid, const char* tcomm = nullptr,
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const char* tcmdline = nullptr, const char* pcomm = nullptr,
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const char* pcmdline = nullptr) {
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std::string forTid;
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if (tid != pid) {
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forTid = " for '" + llkProcGetName(tid, tcomm, tcmdline) + "' (" + std::to_string(tid) + ")";
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}
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LOG(INFO) << "Killing '" << llkProcGetName(pid, pcomm, pcmdline) << "' (" << pid
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<< ") to check forward scheduling progress in " << state << " state" << forTid;
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// CAP_KILL required
|
|
errno = 0;
|
|
auto r = ::kill(pid, SIGKILL);
|
|
if (r) {
|
|
PLOG(ERROR) << "kill(" << pid << ")=" << r << ' ';
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
// Kill one process
|
|
int llkKillOneProcess(pid_t pid, proc* tprocp) {
|
|
return llkKillOneProcess(pid, tprocp->state, tprocp->tid, tprocp->getComm(),
|
|
tprocp->getCmdline());
|
|
}
|
|
|
|
// Kill one process specified by kprocp
|
|
int llkKillOneProcess(proc* kprocp, proc* tprocp) {
|
|
if (kprocp == nullptr) {
|
|
return -2;
|
|
}
|
|
|
|
return llkKillOneProcess(kprocp->tid, tprocp->state, tprocp->tid, tprocp->getComm(),
|
|
tprocp->getCmdline(), kprocp->getComm(), kprocp->getCmdline());
|
|
}
|
|
|
|
// Acquire file descriptor from environment, or open and cache it.
|
|
// NB: cache is unnecessary in our current context, pedantically
|
|
// required to prevent leakage of file descriptors in the future.
|
|
int llkFileToWriteFd(const std::string& file) {
|
|
static std::unordered_map<std::string, int> cache;
|
|
auto search = cache.find(file);
|
|
if (search != cache.end()) return search->second;
|
|
auto fd = android_get_control_file(file.c_str());
|
|
if (fd >= 0) return fd;
|
|
fd = TEMP_FAILURE_RETRY(::open(file.c_str(), O_WRONLY | O_CLOEXEC));
|
|
if (fd >= 0) cache.emplace(std::make_pair(file, fd));
|
|
return fd;
|
|
}
|
|
|
|
// Wrap android::base::WriteStringToFile to use android_get_control_file.
|
|
bool llkWriteStringToFile(const std::string& string, const std::string& file) {
|
|
auto fd = llkFileToWriteFd(file);
|
|
if (fd < 0) return false;
|
|
return android::base::WriteStringToFd(string, fd);
|
|
}
|
|
|
|
bool llkWriteStringToFileConfirm(const std::string& string, const std::string& file) {
|
|
auto fd = llkFileToWriteFd(file);
|
|
auto ret = (fd < 0) ? false : android::base::WriteStringToFd(string, fd);
|
|
std::string content;
|
|
if (!android::base::ReadFileToString(file, &content)) return ret;
|
|
return android::base::Trim(content) == string;
|
|
}
|
|
|
|
void llkPanicKernel(bool dump, pid_t tid, const char* state, const std::string& message = "") {
|
|
if (!message.empty()) LOG(ERROR) << message;
|
|
auto sysrqTriggerFd = llkFileToWriteFd("/proc/sysrq-trigger");
|
|
if (sysrqTriggerFd < 0) {
|
|
// DYB
|
|
llkKillOneProcess(initPid, 'R', tid);
|
|
// The answer to life, the universe and everything
|
|
::exit(42);
|
|
// NOTREACHED
|
|
return;
|
|
}
|
|
// Wish could ::sync() here, if storage is locked up, we will not continue.
|
|
if (dump) {
|
|
// Show all locks that are held
|
|
android::base::WriteStringToFd("d", sysrqTriggerFd);
|
|
// Show all waiting tasks
|
|
android::base::WriteStringToFd("w", sysrqTriggerFd);
|
|
// This can trigger hardware watchdog, that is somewhat _ok_.
|
|
// But useless if pstore configured for <256KB, low ram devices ...
|
|
if (llkEnableSysrqT) {
|
|
android::base::WriteStringToFd("t", sysrqTriggerFd);
|
|
// Show all locks that are held (in case 't' overflows ramoops)
|
|
android::base::WriteStringToFd("d", sysrqTriggerFd);
|
|
// Show all waiting tasks (in case 't' overflows ramoops)
|
|
android::base::WriteStringToFd("w", sysrqTriggerFd);
|
|
}
|
|
::usleep(200000); // let everything settle
|
|
}
|
|
// SysRq message matches kernel format, and propagates through bootstat
|
|
// ultimately to the boot reason into panic,livelock,<state>.
|
|
llkWriteStringToFile(message + (message.empty() ? "" : "\n") +
|
|
"SysRq : Trigger a crash : 'livelock,"s + state + "'\n",
|
|
"/dev/kmsg");
|
|
// Because panic is such a serious thing to do, let us
|
|
// make sure that the tid being inspected still exists!
|
|
auto piddir = procdir + std::to_string(tid) + "/stat";
|
|
if (access(piddir.c_str(), F_OK) != 0) {
|
|
PLOG(WARNING) << piddir;
|
|
return;
|
|
}
|
|
android::base::WriteStringToFd("c", sysrqTriggerFd);
|
|
// NOTREACHED
|
|
// DYB
|
|
llkKillOneProcess(initPid, 'R', tid);
|
|
// I sat at my desk, stared into the garden and thought '42 will do'.
|
|
// I typed it out. End of story
|
|
::exit(42);
|
|
// NOTREACHED
|
|
}
|
|
|
|
void llkAlarmHandler(int) {
|
|
LOG(FATAL) << "alarm";
|
|
// NOTREACHED
|
|
llkPanicKernel(true, ::getpid(), "alarm");
|
|
}
|
|
|
|
milliseconds GetUintProperty(const std::string& key, milliseconds def) {
|
|
return milliseconds(android::base::GetUintProperty(key, static_cast<uint64_t>(def.count()),
|
|
static_cast<uint64_t>(def.max().count())));
|
|
}
|
|
|
|
seconds GetUintProperty(const std::string& key, seconds def) {
|
|
return seconds(android::base::GetUintProperty(key, static_cast<uint64_t>(def.count()),
|
|
static_cast<uint64_t>(def.max().count())));
|
|
}
|
|
|
|
proc* llkTidLookup(pid_t tid) {
|
|
auto search = tids.find(tid);
|
|
if (search == tids.end()) {
|
|
return nullptr;
|
|
}
|
|
return &search->second;
|
|
}
|
|
|
|
void llkTidRemove(pid_t tid) {
|
|
tids.erase(tid);
|
|
}
|
|
|
|
proc* llkTidAlloc(pid_t tid, pid_t pid, pid_t ppid, const char* comm, int time, char state,
|
|
bool frozen) {
|
|
auto it = tids.emplace(std::make_pair(tid, proc(tid, pid, ppid, comm, time, state, frozen)));
|
|
return &it.first->second;
|
|
}
|
|
|
|
std::string llkFormat(milliseconds ms) {
|
|
auto sec = duration_cast<seconds>(ms);
|
|
std::ostringstream s;
|
|
s << sec.count() << '.';
|
|
auto f = s.fill('0');
|
|
auto w = s.width(3);
|
|
s << std::right << (ms - sec).count();
|
|
s.width(w);
|
|
s.fill(f);
|
|
s << 's';
|
|
return s.str();
|
|
}
|
|
|
|
std::string llkFormat(seconds s) {
|
|
return std::to_string(s.count()) + 's';
|
|
}
|
|
|
|
std::string llkFormat(bool flag) {
|
|
return flag ? "true" : "false";
|
|
}
|
|
|
|
std::string llkFormat(const std::unordered_set<std::string>& ignorelist) {
|
|
std::string ret;
|
|
for (const auto& entry : ignorelist) {
|
|
if (!ret.empty()) ret += ",";
|
|
ret += entry;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
std::string llkFormat(
|
|
const std::unordered_map<std::string, std::unordered_set<std::string>>& ignorelist,
|
|
bool leading_comma = false) {
|
|
std::string ret;
|
|
for (const auto& entry : ignorelist) {
|
|
for (const auto& target : entry.second) {
|
|
if (leading_comma || !ret.empty()) ret += ",";
|
|
ret += entry.first + "&" + target;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
// This function parses the properties as a list, incorporating the supplied
|
|
// default. A leading comma separator means preserve the defaults and add
|
|
// entries (with an optional leading + sign), or removes entries with a leading
|
|
// - sign.
|
|
//
|
|
// We only officially support comma separators, but wetware being what they
|
|
// are will take some liberty and I do not believe they should be punished.
|
|
std::unordered_set<std::string> llkSplit(const std::string& prop, const std::string& def) {
|
|
auto s = android::base::GetProperty(prop, def);
|
|
constexpr char separators[] = ", \t:;";
|
|
if (!s.empty() && (s != def) && strchr(separators, s[0])) s = def + s;
|
|
|
|
std::unordered_set<std::string> result;
|
|
|
|
// Special case, allow boolean false to empty the list, otherwise expected
|
|
// source of input from android::base::GetProperty will supply the default
|
|
// value on empty content in the property.
|
|
if (s == "false") return result;
|
|
|
|
size_t base = 0;
|
|
while (s.size() > base) {
|
|
auto found = s.find_first_of(separators, base);
|
|
// Only emplace unique content, empty entries are not an option
|
|
if (found != base) {
|
|
switch (s[base]) {
|
|
case '-':
|
|
++base;
|
|
if (base >= s.size()) break;
|
|
if (base != found) {
|
|
auto have = result.find(s.substr(base, found - base));
|
|
if (have != result.end()) result.erase(have);
|
|
}
|
|
break;
|
|
case '+':
|
|
++base;
|
|
if (base >= s.size()) break;
|
|
if (base == found) break;
|
|
// FALLTHRU (for gcc, lint, pcc, etc; following for clang)
|
|
FALLTHROUGH_INTENDED;
|
|
default:
|
|
result.emplace(s.substr(base, found - base));
|
|
break;
|
|
}
|
|
}
|
|
if (found == s.npos) break;
|
|
base = found + 1;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
bool llkSkipName(const std::string& name,
|
|
const std::unordered_set<std::string>& ignorelist = llkIgnorelistProcess) {
|
|
if (name.empty() || ignorelist.empty()) return false;
|
|
|
|
return ignorelist.find(name) != ignorelist.end();
|
|
}
|
|
|
|
bool llkSkipProc(proc* procp,
|
|
const std::unordered_set<std::string>& ignorelist = llkIgnorelistProcess) {
|
|
if (!procp) return false;
|
|
if (llkSkipName(std::to_string(procp->pid), ignorelist)) return true;
|
|
if (llkSkipName(procp->getComm(), ignorelist)) return true;
|
|
if (llkSkipName(procp->getCmdline(), ignorelist)) return true;
|
|
if (llkSkipName(android::base::Basename(procp->getCmdline()), ignorelist)) return true;
|
|
return false;
|
|
}
|
|
|
|
const std::unordered_set<std::string>& llkSkipName(
|
|
const std::string& name,
|
|
const std::unordered_map<std::string, std::unordered_set<std::string>>& ignorelist) {
|
|
static const std::unordered_set<std::string> empty;
|
|
if (name.empty() || ignorelist.empty()) return empty;
|
|
auto found = ignorelist.find(name);
|
|
if (found == ignorelist.end()) return empty;
|
|
return found->second;
|
|
}
|
|
|
|
bool llkSkipPproc(proc* pprocp, proc* procp,
|
|
const std::unordered_map<std::string, std::unordered_set<std::string>>&
|
|
ignorelist = llkIgnorelistParentAndChild) {
|
|
if (!pprocp || !procp || ignorelist.empty()) return false;
|
|
if (llkSkipProc(procp, llkSkipName(std::to_string(pprocp->pid), ignorelist))) return true;
|
|
if (llkSkipProc(procp, llkSkipName(pprocp->getComm(), ignorelist))) return true;
|
|
if (llkSkipProc(procp, llkSkipName(pprocp->getCmdline(), ignorelist))) return true;
|
|
return llkSkipProc(procp,
|
|
llkSkipName(android::base::Basename(pprocp->getCmdline()), ignorelist));
|
|
}
|
|
|
|
bool llkSkipPid(pid_t pid) {
|
|
return llkSkipName(std::to_string(pid), llkIgnorelistProcess);
|
|
}
|
|
|
|
bool llkSkipPpid(pid_t ppid) {
|
|
return llkSkipName(std::to_string(ppid), llkIgnorelistParent);
|
|
}
|
|
|
|
bool llkSkipUid(uid_t uid) {
|
|
// Match by number?
|
|
if (llkSkipName(std::to_string(uid), llkIgnorelistUid)) {
|
|
return true;
|
|
}
|
|
|
|
// Match by name?
|
|
auto pwd = ::getpwuid(uid);
|
|
return (pwd != nullptr) && __predict_true(pwd->pw_name != nullptr) &&
|
|
__predict_true(pwd->pw_name[0] != '\0') && llkSkipName(pwd->pw_name, llkIgnorelistUid);
|
|
}
|
|
|
|
bool getValidTidDir(dirent* dp, std::string* piddir) {
|
|
if (!::isdigit(dp->d_name[0])) {
|
|
return false;
|
|
}
|
|
|
|
// Corner case can not happen in reality b/c of above ::isdigit check
|
|
if (__predict_false(dp->d_type != DT_DIR)) {
|
|
if (__predict_false(dp->d_type == DT_UNKNOWN)) { // can't b/c procfs
|
|
struct stat st;
|
|
*piddir = procdir;
|
|
*piddir += dp->d_name;
|
|
return (lstat(piddir->c_str(), &st) == 0) && (st.st_mode & S_IFDIR);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
*piddir = procdir;
|
|
*piddir += dp->d_name;
|
|
return true;
|
|
}
|
|
|
|
bool llkIsMonitorState(char state) {
|
|
return (state == 'Z') || (state == 'D');
|
|
}
|
|
|
|
// returns -1 if not found
|
|
long long getSchedValue(const std::string& schedString, const char* key) {
|
|
auto pos = schedString.find(key);
|
|
if (pos == std::string::npos) {
|
|
return -1;
|
|
}
|
|
pos = schedString.find(':', pos);
|
|
if (__predict_false(pos == std::string::npos)) {
|
|
return -1;
|
|
}
|
|
while ((++pos < schedString.size()) && ::isblank(schedString[pos])) {
|
|
;
|
|
}
|
|
long long ret;
|
|
if (!android::base::ParseInt(schedString.substr(pos), &ret, static_cast<long long>(0))) {
|
|
return -1;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
#ifdef __PTRACE_ENABLED__
|
|
bool llkCheckStack(proc* procp, const std::string& piddir) {
|
|
if (llkCheckStackSymbols.empty()) return false;
|
|
if (procp->state == 'Z') { // No brains for Zombies
|
|
procp->stack = -1;
|
|
procp->count_stack = 0ms;
|
|
return false;
|
|
}
|
|
|
|
// Don't check process that are known to block ptrace, save sepolicy noise.
|
|
if (llkSkipProc(procp, llkIgnorelistStack)) return false;
|
|
auto kernel_stack = ReadFile(piddir + "/stack");
|
|
if (kernel_stack.empty()) {
|
|
LOG(VERBOSE) << piddir << "/stack empty comm=" << procp->getComm()
|
|
<< " cmdline=" << procp->getCmdline();
|
|
return false;
|
|
}
|
|
// A scheduling incident that should not reset count_stack
|
|
if (kernel_stack.find(" cpu_worker_pools+0x") != std::string::npos) return false;
|
|
char idx = -1;
|
|
char match = -1;
|
|
std::string matched_stack_symbol = "<unknown>";
|
|
for (const auto& stack : llkCheckStackSymbols) {
|
|
if (++idx < 0) break;
|
|
if ((kernel_stack.find(" "s + stack + "+0x") != std::string::npos) ||
|
|
(kernel_stack.find(" "s + stack + ".cfi+0x") != std::string::npos)) {
|
|
match = idx;
|
|
matched_stack_symbol = stack;
|
|
break;
|
|
}
|
|
}
|
|
if (procp->stack != match) {
|
|
procp->stack = match;
|
|
procp->count_stack = 0ms;
|
|
return false;
|
|
}
|
|
if (match == char(-1)) return false;
|
|
procp->count_stack += llkCycle;
|
|
if (procp->count_stack < llkStateTimeoutMs[llkStateStack]) return false;
|
|
LOG(WARNING) << "Found " << matched_stack_symbol << " in stack for pid " << procp->pid;
|
|
return true;
|
|
}
|
|
#endif
|
|
|
|
// Primary ABA mitigation watching last time schedule activity happened
|
|
void llkCheckSchedUpdate(proc* procp, const std::string& piddir) {
|
|
// Audit finds /proc/<tid>/sched is just over 1K, and
|
|
// is rarely larger than 2K, even less on Android.
|
|
// For example, the "se.avg.lastUpdateTime" field we are
|
|
// interested in typically within the primary set in
|
|
// the first 1K.
|
|
//
|
|
// Proc entries can not be read >1K atomically via libbase,
|
|
// but if there are problems we assume at least a few
|
|
// samples of reads occur before we take any real action.
|
|
std::string schedString = ReadFile(piddir + "/sched");
|
|
if (schedString.empty()) {
|
|
// /schedstat is not as standardized, but in 3.1+
|
|
// Android devices, the third field is nr_switches
|
|
// from /sched:
|
|
schedString = ReadFile(piddir + "/schedstat");
|
|
if (schedString.empty()) {
|
|
return;
|
|
}
|
|
auto val = static_cast<unsigned long long>(-1);
|
|
if (((::sscanf(schedString.c_str(), "%*d %*d %llu", &val)) == 1) &&
|
|
(val != static_cast<unsigned long long>(-1)) && (val != 0) &&
|
|
(val != procp->nrSwitches)) {
|
|
procp->nrSwitches = val;
|
|
procp->count = 0ms;
|
|
procp->killed = !llkTestWithKill;
|
|
}
|
|
return;
|
|
}
|
|
|
|
auto val = getSchedValue(schedString, "\nse.avg.lastUpdateTime");
|
|
if (val == -1) {
|
|
val = getSchedValue(schedString, "\nse.svg.last_update_time");
|
|
}
|
|
if (val != -1) {
|
|
auto schedUpdate = nanoseconds(val);
|
|
if (schedUpdate != procp->schedUpdate) {
|
|
procp->schedUpdate = schedUpdate;
|
|
procp->count = 0ms;
|
|
procp->killed = !llkTestWithKill;
|
|
}
|
|
}
|
|
|
|
val = getSchedValue(schedString, "\nnr_switches");
|
|
if (val != -1) {
|
|
if (static_cast<uint64_t>(val) != procp->nrSwitches) {
|
|
procp->nrSwitches = val;
|
|
procp->count = 0ms;
|
|
procp->killed = !llkTestWithKill;
|
|
}
|
|
}
|
|
}
|
|
|
|
void llkLogConfig(void) {
|
|
LOG(INFO) << "ro.config.low_ram=" << llkFormat(llkLowRam) << "\n"
|
|
<< LLK_ENABLE_SYSRQ_T_PROPERTY "=" << llkFormat(llkEnableSysrqT) << "\n"
|
|
<< LLK_ENABLE_PROPERTY "=" << llkFormat(llkEnable) << "\n"
|
|
<< KHT_ENABLE_PROPERTY "=" << llkFormat(khtEnable) << "\n"
|
|
<< LLK_MLOCKALL_PROPERTY "=" << llkFormat(llkMlockall) << "\n"
|
|
<< LLK_KILLTEST_PROPERTY "=" << llkFormat(llkTestWithKill) << "\n"
|
|
<< KHT_TIMEOUT_PROPERTY "=" << llkFormat(khtTimeout) << "\n"
|
|
<< LLK_TIMEOUT_MS_PROPERTY "=" << llkFormat(llkTimeoutMs) << "\n"
|
|
<< LLK_D_TIMEOUT_MS_PROPERTY "=" << llkFormat(llkStateTimeoutMs[llkStateD]) << "\n"
|
|
<< LLK_Z_TIMEOUT_MS_PROPERTY "=" << llkFormat(llkStateTimeoutMs[llkStateZ]) << "\n"
|
|
#ifdef __PTRACE_ENABLED__
|
|
<< LLK_STACK_TIMEOUT_MS_PROPERTY "=" << llkFormat(llkStateTimeoutMs[llkStateStack])
|
|
<< "\n"
|
|
#endif
|
|
<< LLK_CHECK_MS_PROPERTY "=" << llkFormat(llkCheckMs) << "\n"
|
|
#ifdef __PTRACE_ENABLED__
|
|
<< LLK_CHECK_STACK_PROPERTY "=" << llkFormat(llkCheckStackSymbols) << "\n"
|
|
<< LLK_IGNORELIST_STACK_PROPERTY "=" << llkFormat(llkIgnorelistStack) << "\n"
|
|
#endif
|
|
<< LLK_IGNORELIST_PROCESS_PROPERTY "=" << llkFormat(llkIgnorelistProcess) << "\n"
|
|
<< LLK_IGNORELIST_PARENT_PROPERTY "=" << llkFormat(llkIgnorelistParent)
|
|
<< llkFormat(llkIgnorelistParentAndChild, true) << "\n"
|
|
<< LLK_IGNORELIST_UID_PROPERTY "=" << llkFormat(llkIgnorelistUid);
|
|
}
|
|
|
|
void* llkThread(void* obj) {
|
|
prctl(PR_SET_DUMPABLE, 0);
|
|
|
|
LOG(INFO) << "started";
|
|
|
|
std::string name = std::to_string(::gettid());
|
|
if (!llkSkipName(name)) {
|
|
llkIgnorelistProcess.emplace(name);
|
|
}
|
|
name = static_cast<const char*>(obj);
|
|
prctl(PR_SET_NAME, name.c_str());
|
|
if (__predict_false(!llkSkipName(name))) {
|
|
llkIgnorelistProcess.insert(name);
|
|
}
|
|
// No longer modifying llkIgnorelistProcess.
|
|
llkRunning = true;
|
|
llkLogConfig();
|
|
while (llkRunning) {
|
|
::usleep(duration_cast<microseconds>(llkCheck(true)).count());
|
|
}
|
|
// NOTREACHED
|
|
LOG(INFO) << "exiting";
|
|
return nullptr;
|
|
}
|
|
|
|
} // namespace
|
|
|
|
milliseconds llkCheck(bool checkRunning) {
|
|
if (!llkEnable || (checkRunning != llkRunning)) {
|
|
return milliseconds::max();
|
|
}
|
|
|
|
// Reset internal watchdog, which is a healthy engineering margin of
|
|
// double the maximum wait or cycle time for the mainloop that calls us.
|
|
//
|
|
// This alarm is effectively the live lock detection of llkd, as
|
|
// we understandably can not monitor ourselves otherwise.
|
|
::alarm(duration_cast<seconds>(llkTimeoutMs * 2).count());
|
|
|
|
// kernel jiffy precision fastest acquisition
|
|
static timespec last;
|
|
timespec now;
|
|
::clock_gettime(CLOCK_MONOTONIC_COARSE, &now);
|
|
auto ms = llkGetTimespecDiffMs(&last, &now);
|
|
if (ms < llkCycle) {
|
|
return llkCycle - ms;
|
|
}
|
|
last = now;
|
|
|
|
LOG(VERBOSE) << "opendir(\"" << procdir << "\")";
|
|
if (__predict_false(!llkTopDirectory)) {
|
|
// gid containing AID_READPROC required
|
|
llkTopDirectory.reset(procdir);
|
|
if (__predict_false(!llkTopDirectory)) {
|
|
// Most likely reason we could be here is a resource limit.
|
|
// Keep our processing down to a minimum, but not so low that
|
|
// we do not recover in a timely manner should the issue be
|
|
// transitory.
|
|
LOG(DEBUG) << "opendir(\"" << procdir << "\") failed";
|
|
return llkTimeoutMs;
|
|
}
|
|
}
|
|
|
|
for (auto& it : tids) {
|
|
it.second.updated = false;
|
|
}
|
|
|
|
auto prevUpdate = llkUpdate;
|
|
llkUpdate += ms;
|
|
ms -= llkCycle;
|
|
auto myPid = ::getpid();
|
|
auto myTid = ::gettid();
|
|
auto dump = true;
|
|
for (auto dp = llkTopDirectory.read(); dp != nullptr; dp = llkTopDirectory.read()) {
|
|
std::string piddir;
|
|
|
|
if (!getValidTidDir(dp, &piddir)) {
|
|
continue;
|
|
}
|
|
|
|
// Get the process tasks
|
|
std::string taskdir = piddir + "/task/";
|
|
int pid = -1;
|
|
LOG(VERBOSE) << "+opendir(\"" << taskdir << "\")";
|
|
dir taskDirectory(taskdir);
|
|
if (__predict_false(!taskDirectory)) {
|
|
LOG(DEBUG) << "+opendir(\"" << taskdir << "\") failed";
|
|
}
|
|
for (auto tp = taskDirectory.read(dir::task, dp); tp != nullptr;
|
|
tp = taskDirectory.read(dir::task)) {
|
|
if (!getValidTidDir(tp, &piddir)) {
|
|
continue;
|
|
}
|
|
|
|
// Get the process stat
|
|
std::string stat = ReadFile(piddir + "/stat");
|
|
if (stat.empty()) {
|
|
continue;
|
|
}
|
|
unsigned tid = -1;
|
|
char pdir[TASK_COMM_LEN + 1];
|
|
char state = '?';
|
|
unsigned ppid = -1;
|
|
unsigned utime = -1;
|
|
unsigned stime = -1;
|
|
int dummy;
|
|
pdir[0] = '\0';
|
|
// tid should not change value
|
|
auto match = ::sscanf(
|
|
stat.c_str(),
|
|
"%u (%" ___STRING(
|
|
TASK_COMM_LEN) "[^)]) %c %u %*d %*d %*d %*d %*d %*d %*d %*d %*d %u %u %d",
|
|
&tid, pdir, &state, &ppid, &utime, &stime, &dummy);
|
|
if (pid == -1) {
|
|
pid = tid;
|
|
}
|
|
LOG(VERBOSE) << "match " << match << ' ' << tid << " (" << pdir << ") " << state << ' '
|
|
<< ppid << " ... " << utime << ' ' << stime << ' ' << dummy;
|
|
if (match != 7) {
|
|
continue;
|
|
}
|
|
|
|
// Get the process cgroup
|
|
auto cgroup = ReadFile(piddir + "/cgroup");
|
|
auto frozen = cgroup.find(":freezer:/frozen") != std::string::npos;
|
|
|
|
auto procp = llkTidLookup(tid);
|
|
if (procp == nullptr) {
|
|
procp = llkTidAlloc(tid, pid, ppid, pdir, utime + stime, state, frozen);
|
|
} else {
|
|
// comm can change ...
|
|
procp->setComm(pdir);
|
|
// frozen can change, too...
|
|
procp->setFrozen(frozen);
|
|
procp->updated = true;
|
|
// pid/ppid/tid wrap?
|
|
if (((procp->update != prevUpdate) && (procp->update != llkUpdate)) ||
|
|
(procp->ppid != ppid) || (procp->pid != pid)) {
|
|
procp->reset();
|
|
} else if (procp->time != (utime + stime)) { // secondary ABA.
|
|
// watching utime+stime granularity jiffy
|
|
procp->state = '?';
|
|
}
|
|
procp->update = llkUpdate;
|
|
procp->pid = pid;
|
|
procp->ppid = ppid;
|
|
procp->time = utime + stime;
|
|
if (procp->state != state) {
|
|
procp->count = 0ms;
|
|
procp->killed = !llkTestWithKill;
|
|
procp->state = state;
|
|
} else {
|
|
procp->count += llkCycle;
|
|
}
|
|
}
|
|
|
|
// Filter checks in intuitive order of CPU cost to evaluate
|
|
// If tid unique continue, if ppid or pid unique break
|
|
|
|
if (pid == myPid) {
|
|
break;
|
|
}
|
|
#ifdef __PTRACE_ENABLED__
|
|
// if no stack monitoring, we can quickly exit here
|
|
if (!llkIsMonitorState(state) && llkCheckStackSymbols.empty()) {
|
|
continue;
|
|
}
|
|
#else
|
|
if (!llkIsMonitorState(state)) continue;
|
|
#endif
|
|
if ((tid == myTid) || llkSkipPid(tid)) {
|
|
continue;
|
|
}
|
|
if (procp->isFrozen()) {
|
|
break;
|
|
}
|
|
if (llkSkipPpid(ppid)) {
|
|
break;
|
|
}
|
|
|
|
auto process_comm = procp->getComm();
|
|
if (llkSkipName(process_comm)) {
|
|
continue;
|
|
}
|
|
if (llkSkipName(procp->getCmdline())) {
|
|
break;
|
|
}
|
|
if (llkSkipName(android::base::Basename(procp->getCmdline()))) {
|
|
break;
|
|
}
|
|
|
|
auto pprocp = llkTidLookup(ppid);
|
|
if (pprocp == nullptr) {
|
|
pprocp = llkTidAlloc(ppid, ppid, 0, "", 0, '?', false);
|
|
}
|
|
if (pprocp) {
|
|
if (llkSkipPproc(pprocp, procp)) break;
|
|
if (llkSkipProc(pprocp, llkIgnorelistParent)) break;
|
|
} else {
|
|
if (llkSkipName(std::to_string(ppid), llkIgnorelistParent)) break;
|
|
}
|
|
|
|
if ((llkIgnorelistUid.size() != 0) && llkSkipUid(procp->getUid())) {
|
|
continue;
|
|
}
|
|
|
|
// ABA mitigation watching last time schedule activity happened
|
|
llkCheckSchedUpdate(procp, piddir);
|
|
|
|
#ifdef __PTRACE_ENABLED__
|
|
auto stuck = llkCheckStack(procp, piddir);
|
|
if (llkIsMonitorState(state)) {
|
|
if (procp->count >= llkStateTimeoutMs[(state == 'Z') ? llkStateZ : llkStateD]) {
|
|
stuck = true;
|
|
} else if (procp->count != 0ms) {
|
|
LOG(VERBOSE) << state << ' ' << llkFormat(procp->count) << ' ' << ppid << "->"
|
|
<< pid << "->" << tid << ' ' << process_comm;
|
|
}
|
|
}
|
|
if (!stuck) continue;
|
|
#else
|
|
if (procp->count >= llkStateTimeoutMs[(state == 'Z') ? llkStateZ : llkStateD]) {
|
|
if (procp->count != 0ms) {
|
|
LOG(VERBOSE) << state << ' ' << llkFormat(procp->count) << ' ' << ppid << "->"
|
|
<< pid << "->" << tid << ' ' << process_comm;
|
|
}
|
|
continue;
|
|
}
|
|
#endif
|
|
|
|
// We have to kill it to determine difference between live lock
|
|
// and persistent state blocked on a resource. Is there something
|
|
// wrong with a process that has no forward scheduling progress in
|
|
// Z or D? Yes, generally means improper accounting in the
|
|
// process, but not always ...
|
|
//
|
|
// Whomever we hit with a test kill must accept the Android
|
|
// Aphorism that everything can be burned to the ground and
|
|
// must survive.
|
|
if (procp->killed == false) {
|
|
procp->killed = true;
|
|
// confirm: re-read uid before committing to a panic.
|
|
procp->uid = -1;
|
|
switch (state) {
|
|
case 'Z': // kill ppid to free up a Zombie
|
|
// Killing init will kernel panic without diagnostics
|
|
// so skip right to controlled kernel panic with
|
|
// diagnostics.
|
|
if (ppid == initPid) {
|
|
break;
|
|
}
|
|
LOG(WARNING) << "Z " << llkFormat(procp->count) << ' ' << ppid << "->"
|
|
<< pid << "->" << tid << ' ' << process_comm << " [kill]";
|
|
if ((llkKillOneProcess(pprocp, procp) >= 0) ||
|
|
(llkKillOneProcess(ppid, procp) >= 0)) {
|
|
continue;
|
|
}
|
|
break;
|
|
|
|
case 'D': // kill tid to free up an uninterruptible D
|
|
// If ABA is doing its job, we would not need or
|
|
// want the following. Test kill is a Hail Mary
|
|
// to make absolutely sure there is no forward
|
|
// scheduling progress. The cost when ABA is
|
|
// not working is we kill a process that likes to
|
|
// stay in 'D' state, instead of panicing the
|
|
// kernel (worse).
|
|
default:
|
|
LOG(WARNING) << state << ' ' << llkFormat(procp->count) << ' ' << pid
|
|
<< "->" << tid << ' ' << process_comm << " [kill]";
|
|
if ((llkKillOneProcess(llkTidLookup(pid), procp) >= 0) ||
|
|
(llkKillOneProcess(pid, state, tid) >= 0) ||
|
|
(llkKillOneProcess(procp, procp) >= 0) ||
|
|
(llkKillOneProcess(tid, state, tid) >= 0)) {
|
|
continue;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
// We are here because we have confirmed kernel live-lock
|
|
std::vector<std::string> threads;
|
|
auto taskdir = procdir + std::to_string(tid) + "/task/";
|
|
dir taskDirectory(taskdir);
|
|
for (auto tp = taskDirectory.read(); tp != nullptr; tp = taskDirectory.read()) {
|
|
std::string piddir;
|
|
if (getValidTidDir(tp, &piddir))
|
|
threads.push_back(android::base::Basename(piddir));
|
|
}
|
|
const auto message = state + " "s + llkFormat(procp->count) + " " +
|
|
std::to_string(ppid) + "->" + std::to_string(pid) + "->" +
|
|
std::to_string(tid) + " " + process_comm + " [panic]\n" +
|
|
" thread group: {" + android::base::Join(threads, ",") +
|
|
"}";
|
|
llkPanicKernel(dump, tid,
|
|
(state == 'Z') ? "zombie" : (state == 'D') ? "driver" : "sleeping",
|
|
message);
|
|
dump = false;
|
|
}
|
|
LOG(VERBOSE) << "+closedir()";
|
|
}
|
|
llkTopDirectory.rewind();
|
|
LOG(VERBOSE) << "closedir()";
|
|
|
|
// garbage collection of old process references
|
|
for (auto p = tids.begin(); p != tids.end();) {
|
|
if (!p->second.updated) {
|
|
IF_ALOG(LOG_VERBOSE, LOG_TAG) {
|
|
std::string ppidCmdline = llkProcGetName(p->second.ppid, nullptr, nullptr);
|
|
if (!ppidCmdline.empty()) ppidCmdline = "(" + ppidCmdline + ")";
|
|
std::string pidCmdline;
|
|
if (p->second.pid != p->second.tid) {
|
|
pidCmdline = llkProcGetName(p->second.pid, nullptr, p->second.getCmdline());
|
|
if (!pidCmdline.empty()) pidCmdline = "(" + pidCmdline + ")";
|
|
}
|
|
std::string tidCmdline =
|
|
llkProcGetName(p->second.tid, p->second.getComm(), p->second.getCmdline());
|
|
if (!tidCmdline.empty()) tidCmdline = "(" + tidCmdline + ")";
|
|
LOG(VERBOSE) << "thread " << p->second.ppid << ppidCmdline << "->" << p->second.pid
|
|
<< pidCmdline << "->" << p->second.tid << tidCmdline << " removed";
|
|
}
|
|
p = tids.erase(p);
|
|
} else {
|
|
++p;
|
|
}
|
|
}
|
|
if (__predict_false(tids.empty())) {
|
|
llkTopDirectory.reset();
|
|
}
|
|
|
|
llkCycle = llkCheckMs;
|
|
|
|
timespec end;
|
|
::clock_gettime(CLOCK_MONOTONIC_COARSE, &end);
|
|
auto milli = llkGetTimespecDiffMs(&now, &end);
|
|
LOG((milli > 10s) ? ERROR : (milli > 1s) ? WARNING : VERBOSE) << "sample " << llkFormat(milli);
|
|
|
|
// cap to minimum sleep for 1 second since last cycle
|
|
if (llkCycle < (ms + 1s)) {
|
|
return 1s;
|
|
}
|
|
return llkCycle - ms;
|
|
}
|
|
|
|
unsigned llkCheckMilliseconds() {
|
|
return duration_cast<milliseconds>(llkCheck()).count();
|
|
}
|
|
|
|
bool llkCheckEng(const std::string& property) {
|
|
return android::base::GetProperty(property, "eng") == "eng";
|
|
}
|
|
|
|
bool llkInit(const char* threadname) {
|
|
auto debuggable = android::base::GetBoolProperty("ro.debuggable", false);
|
|
llkLowRam = android::base::GetBoolProperty("ro.config.low_ram", false);
|
|
llkEnableSysrqT &= !llkLowRam;
|
|
if (debuggable) {
|
|
llkEnableSysrqT |= llkCheckEng(LLK_ENABLE_SYSRQ_T_PROPERTY);
|
|
if (!LLK_ENABLE_DEFAULT) { // NB: default is currently true ...
|
|
llkEnable |= llkCheckEng(LLK_ENABLE_PROPERTY);
|
|
khtEnable |= llkCheckEng(KHT_ENABLE_PROPERTY);
|
|
}
|
|
}
|
|
llkEnableSysrqT = android::base::GetBoolProperty(LLK_ENABLE_SYSRQ_T_PROPERTY, llkEnableSysrqT);
|
|
llkEnable = android::base::GetBoolProperty(LLK_ENABLE_PROPERTY, llkEnable);
|
|
if (llkEnable && !llkTopDirectory.reset(procdir)) {
|
|
// Most likely reason we could be here is llkd was started
|
|
// incorrectly without the readproc permissions. Keep our
|
|
// processing down to a minimum.
|
|
llkEnable = false;
|
|
}
|
|
khtEnable = android::base::GetBoolProperty(KHT_ENABLE_PROPERTY, khtEnable);
|
|
llkMlockall = android::base::GetBoolProperty(LLK_MLOCKALL_PROPERTY, llkMlockall);
|
|
llkTestWithKill = android::base::GetBoolProperty(LLK_KILLTEST_PROPERTY, llkTestWithKill);
|
|
// if LLK_TIMOUT_MS_PROPERTY was not set, we will use a set
|
|
// KHT_TIMEOUT_PROPERTY as co-operative guidance for the default value.
|
|
khtTimeout = GetUintProperty(KHT_TIMEOUT_PROPERTY, khtTimeout);
|
|
if (khtTimeout == 0s) {
|
|
khtTimeout = duration_cast<seconds>(llkTimeoutMs * (1 + LLK_CHECKS_PER_TIMEOUT_DEFAULT) /
|
|
LLK_CHECKS_PER_TIMEOUT_DEFAULT);
|
|
}
|
|
llkTimeoutMs =
|
|
khtTimeout * LLK_CHECKS_PER_TIMEOUT_DEFAULT / (1 + LLK_CHECKS_PER_TIMEOUT_DEFAULT);
|
|
llkTimeoutMs = GetUintProperty(LLK_TIMEOUT_MS_PROPERTY, llkTimeoutMs);
|
|
llkValidate(); // validate llkTimeoutMs, llkCheckMs and llkCycle
|
|
llkStateTimeoutMs[llkStateD] = GetUintProperty(LLK_D_TIMEOUT_MS_PROPERTY, llkTimeoutMs);
|
|
llkStateTimeoutMs[llkStateZ] = GetUintProperty(LLK_Z_TIMEOUT_MS_PROPERTY, llkTimeoutMs);
|
|
#ifdef __PTRACE_ENABLED__
|
|
llkStateTimeoutMs[llkStateStack] = GetUintProperty(LLK_STACK_TIMEOUT_MS_PROPERTY, llkTimeoutMs);
|
|
#endif
|
|
llkCheckMs = GetUintProperty(LLK_CHECK_MS_PROPERTY, llkCheckMs);
|
|
llkValidate(); // validate all (effectively minus llkTimeoutMs)
|
|
#ifdef __PTRACE_ENABLED__
|
|
if (debuggable) {
|
|
llkCheckStackSymbols = llkSplit(LLK_CHECK_STACK_PROPERTY, LLK_CHECK_STACK_DEFAULT);
|
|
}
|
|
std::string defaultIgnorelistStack(LLK_IGNORELIST_STACK_DEFAULT);
|
|
if (!debuggable) defaultIgnorelistStack += ",logd,/system/bin/logd";
|
|
llkIgnorelistStack = llkSplit(LLK_IGNORELIST_STACK_PROPERTY, defaultIgnorelistStack);
|
|
#endif
|
|
std::string defaultIgnorelistProcess(
|
|
std::to_string(kernelPid) + "," + std::to_string(initPid) + "," +
|
|
std::to_string(kthreaddPid) + "," + std::to_string(::getpid()) + "," +
|
|
std::to_string(::gettid()) + "," LLK_IGNORELIST_PROCESS_DEFAULT);
|
|
if (threadname) {
|
|
defaultIgnorelistProcess += ","s + threadname;
|
|
}
|
|
for (int cpu = 1; cpu < get_nprocs_conf(); ++cpu) {
|
|
defaultIgnorelistProcess += ",[watchdog/" + std::to_string(cpu) + "]";
|
|
}
|
|
llkIgnorelistProcess = llkSplit(LLK_IGNORELIST_PROCESS_PROPERTY, defaultIgnorelistProcess);
|
|
if (!llkSkipName("[khungtaskd]")) { // ALWAYS ignore as special
|
|
llkIgnorelistProcess.emplace("[khungtaskd]");
|
|
}
|
|
llkIgnorelistParent = llkSplit(LLK_IGNORELIST_PARENT_PROPERTY,
|
|
std::to_string(kernelPid) + "," + std::to_string(kthreaddPid) +
|
|
"," LLK_IGNORELIST_PARENT_DEFAULT);
|
|
// derive llkIgnorelistParentAndChild by moving entries with '&' from above
|
|
for (auto it = llkIgnorelistParent.begin(); it != llkIgnorelistParent.end();) {
|
|
auto pos = it->find('&');
|
|
if (pos == std::string::npos) {
|
|
++it;
|
|
continue;
|
|
}
|
|
auto parent = it->substr(0, pos);
|
|
auto child = it->substr(pos + 1);
|
|
it = llkIgnorelistParent.erase(it);
|
|
|
|
auto found = llkIgnorelistParentAndChild.find(parent);
|
|
if (found == llkIgnorelistParentAndChild.end()) {
|
|
llkIgnorelistParentAndChild.emplace(std::make_pair(
|
|
std::move(parent), std::unordered_set<std::string>({std::move(child)})));
|
|
} else {
|
|
found->second.emplace(std::move(child));
|
|
}
|
|
}
|
|
|
|
llkIgnorelistUid = llkSplit(LLK_IGNORELIST_UID_PROPERTY, LLK_IGNORELIST_UID_DEFAULT);
|
|
|
|
// internal watchdog
|
|
::signal(SIGALRM, llkAlarmHandler);
|
|
|
|
// kernel hung task configuration? Otherwise leave it as-is
|
|
if (khtEnable) {
|
|
// EUID must be AID_ROOT to write to /proc/sys/kernel/ nodes, there
|
|
// are no capability overrides. For security reasons we do not want
|
|
// to run as AID_ROOT. We may not be able to write them successfully,
|
|
// we will try, but the least we can do is read the values back to
|
|
// confirm expectations and report whether configured or not.
|
|
auto configured = llkWriteStringToFileConfirm(std::to_string(khtTimeout.count()),
|
|
"/proc/sys/kernel/hung_task_timeout_secs");
|
|
if (configured) {
|
|
llkWriteStringToFile("65535", "/proc/sys/kernel/hung_task_warnings");
|
|
llkWriteStringToFile("65535", "/proc/sys/kernel/hung_task_check_count");
|
|
configured = llkWriteStringToFileConfirm("1", "/proc/sys/kernel/hung_task_panic");
|
|
}
|
|
if (configured) {
|
|
LOG(INFO) << "[khungtaskd] configured";
|
|
} else {
|
|
LOG(WARNING) << "[khungtaskd] not configurable";
|
|
}
|
|
}
|
|
|
|
bool logConfig = true;
|
|
if (llkEnable) {
|
|
if (llkMlockall &&
|
|
// MCL_ONFAULT pins pages as they fault instead of loading
|
|
// everything immediately all at once. (Which would be bad,
|
|
// because as of this writing, we have a lot of mapped pages we
|
|
// never use.) Old kernels will see MCL_ONFAULT and fail with
|
|
// EINVAL; we ignore this failure.
|
|
//
|
|
// N.B. read the man page for mlockall. MCL_CURRENT | MCL_ONFAULT
|
|
// pins ⊆ MCL_CURRENT, converging to just MCL_CURRENT as we fault
|
|
// in pages.
|
|
|
|
// CAP_IPC_LOCK required
|
|
mlockall(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT) && (errno != EINVAL)) {
|
|
PLOG(WARNING) << "mlockall failed ";
|
|
}
|
|
|
|
if (threadname) {
|
|
pthread_attr_t attr;
|
|
|
|
if (!pthread_attr_init(&attr)) {
|
|
sched_param param;
|
|
|
|
memset(¶m, 0, sizeof(param));
|
|
pthread_attr_setschedparam(&attr, ¶m);
|
|
pthread_attr_setschedpolicy(&attr, SCHED_BATCH);
|
|
if (!pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED)) {
|
|
pthread_t thread;
|
|
if (!pthread_create(&thread, &attr, llkThread, const_cast<char*>(threadname))) {
|
|
// wait a second for thread to start
|
|
for (auto retry = 50; retry && !llkRunning; --retry) {
|
|
::usleep(20000);
|
|
}
|
|
logConfig = !llkRunning; // printed in llkd context?
|
|
} else {
|
|
LOG(ERROR) << "failed to spawn llkd thread";
|
|
}
|
|
} else {
|
|
LOG(ERROR) << "failed to detach llkd thread";
|
|
}
|
|
pthread_attr_destroy(&attr);
|
|
} else {
|
|
LOG(ERROR) << "failed to allocate attibutes for llkd thread";
|
|
}
|
|
}
|
|
} else {
|
|
LOG(DEBUG) << "[khungtaskd] left unconfigured";
|
|
}
|
|
if (logConfig) {
|
|
llkLogConfig();
|
|
}
|
|
|
|
return llkEnable;
|
|
}
|