Commit e4b69aa2 authored Sep 16, 2006 by Kenneth Lee Committed by Linus Torvalds Sep 16, 2006

[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>

parent 1ab7a1f3

kernel/kmod.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}