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Subject: cygwin 3.6.0: Signals may fail permanently if received after SIGSTOP
To: cygwin AT cygwin DOT com
Message-ID: <8c465025-4858-3113-fe2d-ce00dad21f8a@t-online.de>
Date: Mon, 24 Feb 2025 11:29:59 +0100
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From: Christian Franke via Cygwin <cygwin AT cygwin DOT com>
Reply-To: cygwin AT cygwin DOT com
Cc: Christian Franke <Christian DOT Franke AT t-online DOT de>
Sender: "Cygwin" <cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com>

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Found with 'stress-ng --cpu-sched 1':

Testcase (attached):

$ uname -r
3.6.0-0.387.g8cebbb2b42bf.x86_64

$ gcc -o timersig timersig.c

$ ./timersig
638: fork()=639
!!!!!!!!!!!!!...!!!!!!!!!!!!!SIGSTOP: Permission denied
     0 [itimer] timersig 639 sig_send: error sending signal 14, pid 639, 
pipe handle 0x14C, nb 0, packsize 192, Win32 error 0
SIGKILL: Permission denied

$ kill 639
-bash: kill: (639) - Permission denied

$ kill -9 639
-bash: kill: (639) - Permission denied

$ /bin/kill --force 639

$ /bin/kill --force 639
kill: 639: No such process


A similar problem, but without the "error sending signal" message, 
occurs if the timer is not used but the parent process issues SIGSTOP 
SIGALRM SIGCONT ... sequences.

-- 
Regards,
Christian


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