[newlib-cygwin] Cygwin: sigproc: Fix potential race issue regarding exit_state.
Takashi Yano
tyan0@sourceware.org
Mon Nov 22 14:26:21 GMT 2021
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=a496c9cdf8735a878a646c69602bce1682340454
commit a496c9cdf8735a878a646c69602bce1682340454
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date: Sat Nov 20 03:24:18 2021 +0900
Cygwin: sigproc: Fix potential race issue regarding exit_state.
- If sig_send() is called while another thread is processing exit(),
race issue regarding exit_state may occur. This patch fixes the
issue.
Diff:
---
winsup/cygwin/sigproc.cc | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/winsup/cygwin/sigproc.cc b/winsup/cygwin/sigproc.cc
index 2441efc92..4d7d273ae 100644
--- a/winsup/cygwin/sigproc.cc
+++ b/winsup/cygwin/sigproc.cc
@@ -603,11 +603,6 @@ sig_send (_pinfo *p, siginfo_t& si, _cygtls *tls)
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)
sendsig = my_sendsig;
else
@@ -1352,7 +1347,7 @@ wait_sig (VOID *)
sigq.retry = false;
/* Don't process signals when we start exiting */
if (exit_state > ES_EXIT_STARTING && pack.si.si_signo > 0)
- continue;
+ goto skip_process_signal;
sigset_t dummy_mask;
threadlist_t *tl_entry;
@@ -1364,8 +1359,10 @@ wait_sig (VOID *)
pack.mask = &dummy_mask;
}
- sigpacket *q = &sigq.start;
- bool clearwait = false;
+ sigpacket *q;
+ q = &sigq.start;
+ bool clearwait;
+ clearwait = false;
switch (pack.si.si_signo)
{
case __SIGCOMMUNE:
@@ -1462,6 +1459,7 @@ wait_sig (VOID *)
}
if (clearwait && !have_execed)
proc_subproc (PROC_CLEARWAIT, 0);
+skip_process_signal:
if (pack.wakeup)
{
sigproc_printf ("signalling pack.wakeup %p", pack.wakeup);
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