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authorEric W. Biederman <ebiederm@xmission.com>2012-01-13 21:32:59 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2012-01-24 12:12:32 -0800
commitce597919361dcec97341151690e780eade2a9cf4 (patch)
tree7734c3d6a07173cb509be7a2ac7318fd389510bb /fs/sysfs/file.c
parent8381b5e88a19b780f19fc52b7dd67f2b05d07dca (diff)
downloadop-kernel-dev-ce597919361dcec97341151690e780eade2a9cf4.zip
op-kernel-dev-ce597919361dcec97341151690e780eade2a9cf4.tar.gz
sysfs: Complain bitterly about attempts to remove files from nonexistent directories.
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 <ebiederm@xmission.com> Reported-by: Wolfgang Frisch <wfpub@roembden.net> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/sysfs/file.c')
-rw-r--r--fs/sysfs/file.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 62f4fb3..00012e3 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -493,6 +493,12 @@ int sysfs_attr_ns(struct kobject *kobj, const struct attribute *attr,
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;
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