commit: ce597919361dcec97341151690e780eade2a9cf4 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.
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]> Cc: stable <[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 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; diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index 4a802b4..85eb816 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -318,8 +318,11 @@ int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns, const cha 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); -- 1.7.3.4 -- 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
