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[MTE] only upgrade to SYNC mode for MTE crashes

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Bug: 244471804
Test: atest mte_ugprade_test on emulator
Change-Id: Ie974cf2dec96267012f1b01b9a40dad86551b1be
This commit is contained in:
Florian Mayer 2022-09-12 18:19:47 -07:00
parent 61c82abe24
commit d705c2dbcd
3 changed files with 27 additions and 4 deletions
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12
debuggerd/handler/debuggerd_handler.cpp
View file

@ -623,6 +623,18 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c
async_safe_format_log(ANDROID_LOG_ERROR, "libc",
"MTE ERROR DETECTED BUT RUNNING IN PERMISSIVE MODE. CONTINUING.");
pthread_mutex_unlock(&crash_mutex);
} else if (info->si_signo == SIGSEGV && info->si_code == SEGV_MTEAERR && getppid() == 1) {
// Back channel to init (see system/core/init/service.cpp) to signal that
// this process crashed due to an ASYNC MTE fault and should be considered
// for upgrade to SYNC mode. We are re-using the ART profiler signal, which
// is always handled (ignored in native processes, handled for generating a
// dump in ART processes), so a process will never crash from this signal
// except from here.
// The kernel is not particularly receptive to adding this information:
// https://lore.kernel.org/all/20220909180617.374238-1-fmayer@google.com/, so we work around
// like this.
info->si_signo = BIONIC_SIGNAL_ART_PROFILER;
resend_signal(info);
}
#endif
else {

2
init/Android.bp
View file

@ -200,6 +200,7 @@ libinit_cc_defaults {
"libutils",
"libziparchive",
],
header_libs: ["bionic_libc_platform_headers"],
bootstrap: true,
visibility: [":__subpackages__"],
}
@ -529,6 +530,7 @@ cc_library_static {
"libcap",
],
export_include_dirs: ["test_utils/include"], // for tests
header_libs: ["bionic_libc_platform_headers"],
}
// Host Verifier

17
init/service.cpp
View file

@ -42,6 +42,10 @@
#include "service_list.h"
#include "util.h"
#if defined(__BIONIC__)
#include <bionic/reserved_signals.h>
#endif
#ifdef INIT_FULL_SOURCES
#include <ApexProperties.sysprop.h>
#include <android/api-level.h>
@ -323,12 +327,17 @@ void Service::Reap(const siginfo_t& siginfo) {
mount_namespace_.has_value() && *mount_namespace_ == NS_DEFAULT;
const bool is_process_updatable = use_default_mount_ns && is_apex_updatable;
#ifdef SEGV_MTEAERR
#if defined(__BIONIC__) && defined(SEGV_MTEAERR)
// As a precaution, we only upgrade a service once per reboot, to limit
// the potential impact.
// TODO(b/244471804): Once we have a kernel API to get sicode, compare it to MTEAERR here.
bool should_upgrade_mte = siginfo.si_code != CLD_EXITED && siginfo.si_status == SIGSEGV &&
!upgraded_mte_;
//
// BIONIC_SIGNAL_ART_PROFILER is a magic value used by deuggerd to signal
// that the process crashed with SIGSEGV and SEGV_MTEAERR. This signal will
// never be seen otherwise in a crash, because it always gets handled by the
// profiling signal handlers in bionic. See also
// debuggerd/handler/debuggerd_handler.cpp.
bool should_upgrade_mte = siginfo.si_code != CLD_EXITED &&
siginfo.si_status == BIONIC_SIGNAL_ART_PROFILER && !upgraded_mte_;
if (should_upgrade_mte) {
LOG(INFO) << "Upgrading service " << name_ << " to sync MTE";