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Cygwin: sigproc: Fix potential race issue regarding exit_state.

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- If sig_send() is called while another thread is processing exit(),
  race issue regarding exit_state may occur. This patch fixes the
  issue.
This commit is contained in:
Takashi Yano 2021-11-20 03:24:18 +09:00
parent 68faeef4be
commit a496c9cdf8
1 changed files with 6 additions and 8 deletions
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14
winsup/cygwin/sigproc.cc
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@ -603,11 +603,6 @@ sig_send (_pinfo *p, siginfo_t& si, _cygtls *tls)
its_me = false; its_me = false;
} }
/* Do not send signal to myself if exiting, which will be
ignored in wait_sig thread. */
if (its_me && exit_state > ES_EXIT_STARTING && si.si_signo > 0)
goto out;
if (its_me) if (its_me)
sendsig = my_sendsig; sendsig = my_sendsig;
else else
@ -1352,7 +1347,7 @@ wait_sig (VOID *)
sigq.retry = false; sigq.retry = false;
/* Don't process signals when we start exiting */ /* Don't process signals when we start exiting */
if (exit_state > ES_EXIT_STARTING && pack.si.si_signo > 0) if (exit_state > ES_EXIT_STARTING && pack.si.si_signo > 0)
continue; goto skip_process_signal;
sigset_t dummy_mask; sigset_t dummy_mask;
threadlist_t *tl_entry; threadlist_t *tl_entry;
@ -1364,8 +1359,10 @@ wait_sig (VOID *)
pack.mask = &dummy_mask; pack.mask = &dummy_mask;
} }
sigpacket *q = &sigq.start; sigpacket *q;
bool clearwait = false; q = &sigq.start;
bool clearwait;
clearwait = false;
switch (pack.si.si_signo) switch (pack.si.si_signo)
{ {
case __SIGCOMMUNE: case __SIGCOMMUNE:
@ -1462,6 +1459,7 @@ wait_sig (VOID *)
} }
if (clearwait && !have_execed) if (clearwait && !have_execed)
proc_subproc (PROC_CLEARWAIT, 0); proc_subproc (PROC_CLEARWAIT, 0);
skip_process_signal:
if (pack.wakeup) if (pack.wakeup)
{ {
sigproc_printf ("signalling pack.wakeup %p", pack.wakeup); sigproc_printf ("signalling pack.wakeup %p", pack.wakeup);