PR/54618 CVS commit: src/sys/kern

["Kamil Rytarowski" <kamil%netbsd.org@localhost>]

The following reply was made to PR kern/54618; it has been noted by GNATS.

From: "Kamil Rytarowski" <kamil%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/54618 CVS commit: src/sys/kern
Date: Tue, 15 Oct 2019 13:59:57 +0000

 Module Name:	src
 Committed By:	kamil
 Date:		Tue Oct 15 13:59:57 UTC 2019
 
 Modified Files:
 	src/sys/kern: kern_sig.c
 
 Log Message:
 Remove the short-circuit lwp_exit() path from sigswitch()
 
 sigswitch() can be called from exit1() through:
 
    ttywait()->ttysleep()-> cv_timedwait_sig()->sleepq_block()->issignal()->sigswitch()
 
 lwp_exit() called for the last LWP triggers exit1() and this causes a panic.
 
 The debugger related signals have short-circuit demise paths in
 eventswitch() and other functions, before calling sigswitch().
 
 This change restores the original behavior, but there is an open question
 whether the kernel crash is a red herring of misbehavior of ttywait().
 
 This should fix PR kern/54618 by David H. Gutteridge
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.372 -r1.373 src/sys/kern/kern_sig.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.