CVS commit: src/sys/kern

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

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.