From e4b69aa2a1bcee21f8d5e089b8682dd8aaace5eb Mon Sep 17 00:00:00 2001
From: Kenneth Lee <kenlee@dg.gov.cn>
Date: Sat, 16 Sep 2006 12:15:55 -0700
Subject: [PATCH] [PATCH] bug fix in kernel/kmod.c
I think there is a bug in kmod.c: In __call_usermodehelper(), when
kernel_thread(wait_for_helper, ...) return success, since wait_for_helper()
might call complete() at any time, the sub_info should not be used any
more.
Normally wait_for_helper() take a long time to finish, you may not get
problem for most of the case. But if you remove /sbin/modprobe, it may
become easier for you to get a oop in khelper.
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
kernel/kmod.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 1d32defa38ab..5c470c57fb57 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -197,11 +197,12 @@ static void __call_usermodehelper(void *data)
{
struct subprocess_info *sub_info = data;
pid_t pid;
+ int wait = sub_info->wait;
/* CLONE_VFORK: wait until the usermode helper has execve'd
* successfully We need the data structures to stay around
* until that is done. */
- if (sub_info->wait)
+ if (wait)
pid = kernel_thread(wait_for_helper, sub_info,
CLONE_FS | CLONE_FILES | SIGCHLD);
else
@@ -211,7 +212,7 @@ static void __call_usermodehelper(void *data)
if (pid < 0) {
sub_info->retval = pid;
complete(sub_info->complete);
- } else if (!sub_info->wait)
+ } else if (!wait)
complete(sub_info->complete);
}