This is a note to let you know that I've just added the patch titled
sysfs: Complain bitterly about attempts to remove files from nonexistent
directories.
to the 3.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sysfs-complain-bitterly-about-attempts-to-remove-files-from-nonexistent-directories.patch
and it can be found in the queue-3.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From ce597919361dcec97341151690e780eade2a9cf4 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <[email protected]>
Date: Fri, 13 Jan 2012 21:32:59 -0800
Subject: sysfs: Complain bitterly about attempts to remove files from
nonexistent directories.
From: "Eric W. Biederman" <[email protected]>
commit ce597919361dcec97341151690e780eade2a9cf4 upstream.
Recently an OOPS was observed from the usb serial io_ti driver when it tried to
remove
sysfs directories. Upon investigation it turns out this driver was always buggy
and that a recent sysfs change had stopped guarding itself against removing
attributes
from sysfs directories that had already been removed. :(
Historically we have been silent about attempting to files from nonexistent
sysfs
directories and have politely returned error codes. That has resulted in
people writing
broken code that ignores the error codes.
Issue a kernel WARNING and a stack backtrace to make it clear in no uncertain
terms that abusing sysfs is not ok, and the callers need to fix their code.
This change transforms the io_ti OOPS into a more comprehensible error message
and stack backtrace.
Signed-off-by: Eric W. Biederman <[email protected]>
Reported-by: Wolfgang Frisch <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/sysfs/file.c | 6 ++++++
fs/sysfs/inode.c | 5 ++++-
2 files changed, 10 insertions(+), 1 deletion(-)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -493,6 +493,12 @@ int sysfs_attr_ns(struct kobject *kobj,
const void *ns = NULL;
int err;
+ if (!dir_sd) {
+ WARN(1, KERN_ERR "sysfs: kobject %s without dirent\n",
+ kobject_name(kobj));
+ return -ENOENT;
+ }
+
err = 0;
if (!sysfs_ns_type(dir_sd))
goto out;
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -318,8 +318,11 @@ int sysfs_hash_and_remove(struct sysfs_d
struct sysfs_addrm_cxt acxt;
struct sysfs_dirent *sd;
- if (!dir_sd)
+ if (!dir_sd) {
+ WARN(1, KERN_WARNING "sysfs: can not remove '%s', no
directory\n",
+ name);
return -ENOENT;
+ }
sysfs_addrm_start(&acxt, dir_sd);
Patches currently in stable-queue which might be from [email protected] are
queue-3.2/sysfs-complain-bitterly-about-attempts-to-remove-files-from-nonexistent-directories.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
