PR/38637 CVS commit: src/sys/kern

[Manuel Bouyer <bouyer%netbsd.org@localhost>]

The following reply was made to PR kern/38637; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/38637 CVS commit: src/sys/kern
Date: Tue, 5 May 2009 20:26:37 +0000

 Module Name:   src
 Committed By:  bouyer
 Date:          Tue May  5 20:26:36 UTC 2009
 
 Modified Files:
        src/sys/kern: kern_softint.c
 
 Log Message:
 Declare sh_flags volatile.
 Without it, on ports where splhigh() is inline, the compiler will optimise
 the second SOFTINT_PENDING test in softint_schedule(). A dissasembly
 of softint_schedule() with and without the volatile sh_flags confirm this
 on sparc.
 Because of this there is a race that could lead to the softhand_t
 being enqueued twice on si_q, leading to a corrupted queue and
 some handler being SOFTINT_PENDING but never called.
 
 Should fix PR kern/38637
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.26 -r1.27 src/sys/kern/kern_softint.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.