linux/fs/9p
David Howells f89ea63f1c
netfs, 9p: Fix race between umount and async request completion
There's a problem in 9p's interaction with netfslib whereby a crash occurs
because the 9p_fid structs get forcibly destroyed during client teardown
(without paying attention to their refcounts) before netfslib has finished
with them.  However, it's not a simple case of deferring the clunking that
p9_fid_put() does as that requires the p9_client record to still be
present.

The problem is that netfslib has to unlock pages and clear the IN_PROGRESS
flag before destroying the objects involved - including the fid - and, in
any case, nothing checks to see if writeback completed barring looking at
the page flags.

Fix this by keeping a count of outstanding I/O requests (of any type) and
waiting for it to quiesce during inode eviction.

Reported-by: syzbot+df038d463cca332e8414@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/0000000000005be0aa061846f8d6@google.com/
Reported-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000b86c5e06130da9c6@google.com/
Reported-by: syzbot+1527696d41a634cc1819@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000041f960618206d7e@google.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/755891.1716560771@warthog.procyon.org.uk
Tested-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Hillf Danton <hdanton@sina.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Reported-and-tested-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-05-27 13:12:13 +02:00
..
acl.c fs: port inode_owner_or_capable() to mnt_idmap 2023-01-19 09:24:29 +01:00
acl.h fs: port ->set_acl() to pass mnt_idmap 2023-01-19 09:24:27 +01:00
cache.c mm, netfs, fscache: stop read optimisation when folio removed from pagecache 2023-08-18 10:12:13 -07:00
cache.h fs/9p: Rework cache modes and add new options to Documentation 2023-04-09 21:41:21 +00:00
fid.c fs/9p: remove writeback fid and fix per-file modes 2023-03-27 02:33:48 +00:00
fid.h fs/9p: fix the cache always being enabled on files with qid flags 2024-03-28 15:10:29 +00:00
Kconfig 9p: Remove INET dependency 2023-05-04 21:46:57 +01:00
Makefile
v9fs_vfs.h fs/9p: simplify iget to remove unnecessary paths 2024-01-26 16:46:56 +00:00
v9fs.c mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
v9fs.h fs/9p: mitigate inode collisions 2024-04-22 15:34:27 +00:00
vfs_addr.c netfs: Remove the old writeback code 2024-05-01 18:07:38 +01:00
vfs_dentry.c 9p: Remove INET dependency 2023-05-04 21:46:57 +01:00
vfs_dir.c fs/9p: rework qid2ino logic 2024-01-26 16:46:56 +00:00
vfs_file.c 9p: explicitly deny setlease attempts 2024-03-28 19:52:55 +00:00
vfs_inode_dotl.c fs/9p: mitigate inode collisions 2024-04-22 15:34:27 +00:00
vfs_inode.c netfs, 9p: Fix race between umount and async request completion 2024-05-27 13:12:13 +02:00
vfs_super.c fs/9p: mitigate inode collisions 2024-04-22 15:34:27 +00:00
xattr.c Bunch of small fixes: 2023-11-04 09:20:04 -10:00
xattr.h 9p: move xattr-related structs to .rodata 2023-10-09 16:24:16 +02:00