104 lines
4.4 KiB
Diff
104 lines
4.4 KiB
Diff
commit eee2c95b91b2fdcb36c0b1a2ab15df4a44ee2986
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Author: philippe <philippe@a5019735-40e9-0310-863c-91ae7b9d1cf9>
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Date: Sat Nov 19 13:51:41 2016 +0000
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Fix Bug 372600 - process loops forever when fatal signals are arriving quickly
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git-svn-id: svn://svn.valgrind.org/valgrind/trunk@16140 a5019735-40e9-0310-863c-91ae7b9d1cf9
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diff --git a/coregrind/m_signals.c b/coregrind/m_signals.c
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index 168b681..b398882 100644
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--- a/coregrind/m_signals.c
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+++ b/coregrind/m_signals.c
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@@ -2430,8 +2430,14 @@ void async_signalhandler ( Int sigNo,
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info->si_code = sanitize_si_code(info->si_code);
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if (VG_(clo_trace_signals))
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- VG_(dmsg)("async signal handler: signal=%d, tid=%u, si_code=%d\n",
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- sigNo, tid, info->si_code);
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+ VG_(dmsg)("async signal handler: signal=%d, tid=%u, si_code=%d, "
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+ "exitreason %s\n",
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+ sigNo, tid, info->si_code,
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+ VG_(name_of_VgSchedReturnCode)(tst->exitreason));
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+
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+ /* */
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+ if (tst->exitreason == VgSrc_FatalSig)
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+ resume_scheduler(tid);
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/* Update thread state properly. The signal can only have been
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delivered whilst we were in
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@@ -2479,8 +2485,16 @@ void async_signalhandler ( Int sigNo,
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);
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/* (2) */
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- /* Set up the thread's state to deliver a signal */
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- if (!is_sig_ign(info, tid))
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+ /* Set up the thread's state to deliver a signal.
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+ However, if exitreason is VgSrc_FatalSig, then thread tid was
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+ taken out of a syscall by VG_(nuke_all_threads_except).
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+ But after the emission of VKI_SIGKILL, another (fatal) async
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+ signal might be sent. In such a case, we must not handle this
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+ signal, as the thread is supposed to die first.
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+ => resume the scheduler for such a thread, so that the scheduler
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+ can let the thread die. */
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+ if (tst->exitreason != VgSrc_FatalSig
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+ && !is_sig_ign(info, tid))
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deliver_signal(tid, info, uc);
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/* It's crucial that (1) and (2) happen in the order (1) then (2)
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@@ -2946,6 +2960,20 @@ void VG_(poll_signals)(ThreadId tid)
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ThreadState *tst = VG_(get_ThreadState)(tid);
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vki_sigset_t saved_mask;
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+ if (tst->exitreason == VgSrc_FatalSig) {
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+ /* This task has been requested to die due to a fatal signal
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+ received by the process. So, we cannot poll new signals,
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+ as we are supposed to die asap. If we would poll and deliver
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+ a new (maybe fatal) signal, this could cause a deadlock, as
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+ this thread would believe it has to terminate the other threads
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+ and wait for them to die, while we already have a thread doing
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+ that. */
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+ if (VG_(clo_trace_signals))
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+ VG_(dmsg)("poll_signals: not polling as thread %u is exitreason %s\n",
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+ tid, VG_(name_of_VgSchedReturnCode)(tst->exitreason));
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+ return;
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+ }
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+
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/* look for all the signals this thread isn't blocking */
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/* pollset = ~tst->sig_mask */
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VG_(sigcomplementset)( &pollset, &tst->sig_mask );
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@@ -2961,15 +2989,18 @@ void VG_(poll_signals)(ThreadId tid)
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/* If there was nothing queued, ask the kernel for a pending signal */
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if (sip == NULL && VG_(sigtimedwait_zero)(&pollset, &si) > 0) {
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if (VG_(clo_trace_signals))
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- VG_(dmsg)("poll_signals: got signal %d for thread %u\n",
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- si.si_signo, tid);
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+ VG_(dmsg)("poll_signals: got signal %d for thread %u exitreason %s\n",
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+ si.si_signo, tid,
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+ VG_(name_of_VgSchedReturnCode)(tst->exitreason));
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sip = &si;
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}
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if (sip != NULL) {
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/* OK, something to do; deliver it */
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if (VG_(clo_trace_signals))
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- VG_(dmsg)("Polling found signal %d for tid %u\n", sip->si_signo, tid);
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+ VG_(dmsg)("Polling found signal %d for tid %u exitreason %s\n",
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+ sip->si_signo, tid,
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+ VG_(name_of_VgSchedReturnCode)(tst->exitreason));
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if (!is_sig_ign(sip, tid))
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deliver_signal(tid, sip, NULL);
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else if (VG_(clo_trace_signals))
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@@ -3073,7 +3104,8 @@ void VG_(sigstartup_actions) ( void )
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}
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if (VG_(clo_trace_signals))
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- VG_(dmsg)("Max kernel-supported signal is %d\n", VG_(max_signal));
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+ VG_(dmsg)("Max kernel-supported signal is %d, VG_SIGVGKILL is %d\n",
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+ VG_(max_signal), VG_SIGVGKILL);
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/* Our private internal signals are treated as ignored */
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scss.scss_per_sig[VG_SIGVGKILL].scss_handler = VKI_SIG_IGN;
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