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Merge pull request #41154 from rzarzynski/wip-global-backtrace-bug-50647

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global: fault handlers cope with simultaneous faults now.

Reviewed-by: Kefu Chai <kchai@redhat.com>
This commit is contained in:
Kefu Chai 2021-06-05 21:41:00 +08:00 committed by GitHub
commit 0d38c8a668
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 28 additions and 12 deletions
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40
src/global/signal_handler.cc
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@ -84,6 +84,7 @@ void sighup_handler(int signum)
static void reraise_fatal(int signum)
{
// Use default handler to dump core
signal(signum, SIG_DFL);
int ret = raise(signum);
// Normally, we won't get here. If we do, something is very weird.
@ -144,11 +145,26 @@ static int parse_from_os_release(
return 0;
}
static void handle_fatal_signal(int signum)
static void handle_oneshot_fatal_signal(int signum)
{
// This code may itself trigger a SIGSEGV if the heap is corrupt. In that
// case, SA_RESETHAND specifies that the default signal handler--
// presumably dump core-- will handle it.
constexpr static pid_t NULL_TID{0};
static std::atomic<pid_t> handler_tid{NULL_TID};
if (auto expected{NULL_TID};
!handler_tid.compare_exchange_strong(expected, ceph_gettid())) {
if (expected == ceph_gettid()) {
// The handler code may itself trigger a SIGSEGV if the heap is corrupt.
// In that case, SIG_DFL followed by return specifies that the default
// signal handler -- presumably dump core -- will handle it.
signal(signum, SIG_DFL);
} else {
// Huh, another thread got into troubles while we are handling the fault.
// If this is i.e. SIGSEGV handler, returning means retrying the faulty
// instruction one more time, and thus all those extra threads will run
// into a busy-wait basically.
}
return;
}
char buf[1024];
char pthread_name[16] = {0}; //limited by 16B include terminating null byte.
int r = ceph_pthread_getname(pthread_self(), pthread_name, sizeof(pthread_name));
@ -335,14 +351,14 @@ static void handle_fatal_signal(int signum)
void install_standard_sighandlers(void)
{
install_sighandler(SIGSEGV, handle_fatal_signal, SA_RESETHAND | SA_NODEFER);
install_sighandler(SIGABRT, handle_fatal_signal, SA_RESETHAND | SA_NODEFER);
install_sighandler(SIGBUS, handle_fatal_signal, SA_RESETHAND | SA_NODEFER);
install_sighandler(SIGILL, handle_fatal_signal, SA_RESETHAND | SA_NODEFER);
install_sighandler(SIGFPE, handle_fatal_signal, SA_RESETHAND | SA_NODEFER);
install_sighandler(SIGXCPU, handle_fatal_signal, SA_RESETHAND | SA_NODEFER);
install_sighandler(SIGXFSZ, handle_fatal_signal, SA_RESETHAND | SA_NODEFER);
install_sighandler(SIGSYS, handle_fatal_signal, SA_RESETHAND | SA_NODEFER);
install_sighandler(SIGSEGV, handle_oneshot_fatal_signal, SA_NODEFER);
install_sighandler(SIGABRT, handle_oneshot_fatal_signal, SA_NODEFER);
install_sighandler(SIGBUS, handle_oneshot_fatal_signal, SA_NODEFER);
install_sighandler(SIGILL, handle_oneshot_fatal_signal, SA_NODEFER);
install_sighandler(SIGFPE, handle_oneshot_fatal_signal, SA_NODEFER);
install_sighandler(SIGXCPU, handle_oneshot_fatal_signal, SA_NODEFER);
install_sighandler(SIGXFSZ, handle_oneshot_fatal_signal, SA_NODEFER);
install_sighandler(SIGSYS, handle_oneshot_fatal_signal, SA_NODEFER);
}