[PATCH 3/3] Cygwin: signal: Fix a problem that process hangs on exit

[Takashi Yano]

The process that receives many SIGSTOP/SIGCONT signals sometimes hangs
on exit in sig_dispatch_pending(). This patch avoids processing signals
in sig_dispatch_pending() as if __SIGFLASHFAST is used.

Addresses: https://cygwin.com/pipermail/cygwin/2025-February/257473.html
Fixes: d243e51ef1d3 ("Cygwin: signal: Fix deadlock between main thread and sig thread")
Reported-by: Christian Franke <Christian.Franke@t-online.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
---
 winsup/cygwin/sigproc.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/sigproc.cc b/winsup/cygwin/sigproc.cc
index 8739f18f5..7cfa37d8f 100644
--- a/winsup/cygwin/sigproc.cc
+++ b/winsup/cygwin/sigproc.cc
@@ -743,7 +743,8 @@ sig_send (_pinfo *p, siginfo_t& si, _cygtls *tls)
     }
 
   unsigned cw_mask;
-  cw_mask = pack.si.si_signo == __SIGFLUSHFAST ? 0 : cw_sig_restart;
+  cw_mask =
+    (pack.si.si_signo == __SIGFLUSHFAST || exit_state) ? 0 : cw_sig_restart;
 
   DWORD nb;
   BOOL res;
-- 
2.45.1