Subject: bug#20471: Emacs ceased to respond to C-g on a tty; SIGINT became blocked?

From: Ivan Shmakov <[email-masked]>
Date: Thu, 2 Jun 2022 05:20:47 +0000

>>>>> On 2022-05-02, Lars Ingebrigtsen wrote:
>>>>> IS == Ivan Shmakov wrote:

 > (I’m going through old bug reports that unfortunately weren’t resolved
 > at the time.)

 > Are you still seeing this issue in recent Emacs versions?

	I haven’t put Emacs to much use in a couple of years, so that’d
	be a no.  I cannot readily recall which versions I’ve had this
	bug on, but while very rare (perhaps only happening once in a few
	weeks), I’m pretty certain I’ve encountered it more than once.

 IS> After some unfortunate interaction with a process (or perhaps a
 IS> network connection), one of my Emacs instances (built from Git;
 IS> 1c7f0cdc4c1f, 2015-04-27 16:59:11 UTC) ceased to respond to C-g
 IS> on a tty.

 IS> Attaching GDB to it shows no signals being delivered on C-g,
 IS> which (AIUI) hints at either SIGINT being blocked /or/ C-g
 IS> “unbound” from the signal via terminal settings.

 IS> $ ps -o pid,pending,blocked,ignored,caught,stat,bsdtime,command \
 IS>       -C emacs24 -C emacs25 
 IS>   PID   PENDING   BLOCKED   IGNORED    CAUGHT STAT   TIME COMMAND
 IS> 19987  00000000  00000000  14001000 <cb816eff S+   843:01 emacs24
 IS> 25806  00000002  04002006  04001000 <db816eff Sl+   52:00 emacs25
 IS> $ 

	AIUI, bit 1 set (as in, ‘0 != (mask & 2)’) in the ‘blocked’
	mask above suggests that signal 2 (SIGINT) was indeed blocked.
	Ditto for ‘pending.’

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