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Merge "llkd: make 100% sure process that triggers panic still exists"

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Mark Salyzyn 2018-12-14 20:35:08 +00:00 committed by Gerrit Code Review
commit 00289c9c79
1 changed files with 12 additions and 4 deletions
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16
llkd/libllkd.cpp
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@ -510,9 +510,7 @@ bool llkWriteStringToFileConfirm(const std::string& string, const std::string& f
return android::base::Trim(content) == string;
}
void llkPanicKernel(bool dump, pid_t tid, const char* state,
const std::string& message = "") __noreturn;
void llkPanicKernel(bool dump, pid_t tid, const char* state, const std::string& message) {
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) {
@ -521,6 +519,7 @@ void llkPanicKernel(bool dump, pid_t tid, const char* state, const std::string&
// The answer to life, the universe and everything
::exit(42);
// NOTREACHED
return;
}
::sync();
if (dump) {
@ -544,6 +543,13 @@ void llkPanicKernel(bool dump, pid_t tid, const char* state, const std::string&
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
@ -909,6 +915,7 @@ milliseconds llkCheck(bool checkRunning) {
ms -= llkCycle;
auto myPid = ::getpid();
auto myTid = ::gettid();
auto dump = true;
for (auto dp = llkTopDirectory.read(); dp != nullptr; dp = llkTopDirectory.read()) {
std::string piddir;
@ -1109,9 +1116,10 @@ milliseconds llkCheck(bool checkRunning) {
const auto message = state + " "s + llkFormat(procp->count) + " " +
std::to_string(ppid) + "->" + std::to_string(pid) + "->" +
std::to_string(tid) + " " + procp->getComm() + " [panic]";
llkPanicKernel(true, tid,
llkPanicKernel(dump, tid,
(state == 'Z') ? "zombie" : (state == 'D') ? "driver" : "sleeping",
message);
dump = false;
}
LOG(VERBOSE) << "+closedir()";
}