Messages in this thread Patch in this message | | | Date | Fri, 18 Aug 2006 13:46:07 +0200 | From | Björn Steinbrink <> | Subject | [PATCH] Fix ____call_usermodehelper errors being silently ignored |
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If ____call_usermodehelper fails, we're not interested in the child process' exit value, but the real error, so let's stop wait_for_helper from overwriting it in that case.
Issue discovered by Benedikt Böhm while working on a Linux-VServer usermode helper.
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
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diff --git a/kernel/kmod.c b/kernel/kmod.c index 1d32def..eab8f31 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -176,6 +176,8 @@ static int wait_for_helper(void *data) if (pid < 0) { sub_info->retval = pid; } else { + int ret; + /* * Normally it is bogus to call wait4() from in-kernel because * wait4() wants to write the exit code to a userspace address. @@ -185,7 +187,15 @@ static int wait_for_helper(void *data) * * Thus the __user pointer cast is valid here. */ - sys_wait4(pid, (int __user *) &sub_info->retval, 0, NULL); + sys_wait4(pid, (int __user *)&ret, 0, NULL); + + /* + * If ret is 0, either ____call_usermodehelper failed and the + * real error code is already in sub_info->retval or + * sub_info->retval is 0 anyway, so don't mess with it then. + */ + if (ret) + sub_info->retval = ret; } complete(sub_info->complete); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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