The patch titled
Fix ____call_usermodehelper errors being silently ignored
has been added to the -mm tree. Its filename is
fix-____call_usermodehelper-errors-being-silently-ignored.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Fix ____call_usermodehelper errors being silently ignored
From: Björn Steinbrink <B.Steinbrink@xxxxxx>
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@xxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/kmod.c | 12 +++++++++++-
1 files changed, 11 insertions(+), 1 deletion(-)
diff -puN kernel/kmod.c~fix-____call_usermodehelper-errors-being-silently-ignored kernel/kmod.c
--- a/kernel/kmod.c~fix-____call_usermodehelper-errors-being-silently-ignored
+++ a/kernel/kmod.c
@@ -191,6 +191,8 @@ 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.
@@ -200,7 +202,15 @@ 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);
_
Patches currently in -mm which might be from B.Steinbrink@xxxxxx are
fix-____call_usermodehelper-errors-being-silently-ignored.patch
-
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