** Changed in: linux (Ubuntu Disco)
Status: Fix Committed => Won't Fix
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1856949
Title:
cifs: kernel NULL pointer dereference, address: 0000000000000038
Status in linux package in Ubuntu:
Fix Committed
Status in linux source package in Xenial:
Fix Released
Status in linux source package in Bionic:
Fix Committed
Status in linux source package in Disco:
Won't Fix
Status in linux source package in Eoan:
Fix Committed
Bug description:
[Impact]
Currently when the client creates a cifsFileInfo structure for
a newly opened file, it allocates a list of byte-range locks
with a pointer to the new cfile and attaches this list to the
inode's lock list. The latter happens before initializing all
other fields, e.g. cfile->tlink. Thus a partially initialized
cifsFileInfo structure becomes available to other threads that
walk through the inode's lock list. One example of such a thread
may be an oplock break worker thread that tries to push all
cached byte-range locks. This causes NULL-pointer dereference
in smb2_push_mandatory_locks() when accessing cfile->tlink:
[598428.945633] BUG: kernel NULL pointer dereference, address:
0000000000000038
...
[598428.945749] Workqueue: cifsoplockd cifs_oplock_break [cifs]
[598428.945793] RIP: 0010:smb2_push_mandatory_locks+0xd6/0x5a0 [cifs]
...
[598428.945834] Call Trace:
[598428.945870] ? cifs_revalidate_mapping+0x45/0x90 [cifs]
[598428.945901] cifs_oplock_break+0x13d/0x450 [cifs]
[598428.945909] process_one_work+0x1db/0x380
[598428.945914] worker_thread+0x4d/0x400
[598428.945921] kthread+0x104/0x140
[598428.945925] ? process_one_work+0x380/0x380
[598428.945931] ? kthread_park+0x80/0x80
[598428.945937] ret_from_fork+0x35/0x40
[Test Case]
TBD.
[Fix]
Backport commit 6f582b273ec23332074d970a7fb25bef835df71f ("CIFS: Fix
NULL-pointer dereference in smb2_push_mandatory_locks")
[Regression Potential]
Low. The patch is fairly simple and it's tagged for stable kernels. In
fact it is already in some of the released upstream stable kernels.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1856949/+subscriptions
--
Mailing list: https://launchpad.net/~kernel-packages
Post to : kernel-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~kernel-packages
More help : https://help.launchpad.net/ListHelp
