This is a note to let you know that I've just added the patch titled
io_uring/rw: defer fsnotify calls to task context
to the 5.15-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:
io_uring-rw-defer-fsnotify-calls-to-task-context.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d555c91cfc2f24961e823f0c717e2fcf92a8ed6a
Author: Jens Axboe <axboe@xxxxxxxxx>
Date: Sat Jan 21 13:38:51 2023 -0700
io_uring/rw: defer fsnotify calls to task context
commit b000145e9907809406d8164c3b2b8861d95aecd1 upstream.
We can't call these off the kiocb completion as that might be off
soft/hard irq context. Defer the calls to when we process the
task_work for this request. That avoids valid complaints like:
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc6-syzkaller-00321-g105a36f3694e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_usage_bug kernel/locking/lockdep.c:3961 [inline]
valid_state kernel/locking/lockdep.c:3973 [inline]
mark_lock_irq kernel/locking/lockdep.c:4176 [inline]
mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632
mark_lock kernel/locking/lockdep.c:4596 [inline]
mark_usage kernel/locking/lockdep.c:4527 [inline]
__lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
__fs_reclaim_acquire mm/page_alloc.c:4674 [inline]
fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688
might_alloc include/linux/sched/mm.h:271 [inline]
slab_pre_alloc_hook mm/slab.h:700 [inline]
slab_alloc mm/slab.c:3278 [inline]
__kmem_cache_alloc_lru mm/slab.c:3471 [inline]
kmem_cache_alloc+0x39/0x520 mm/slab.c:3491
fanotify_alloc_fid_event fs/notify/fanotify/fanotify.c:580 [inline]
fanotify_alloc_event fs/notify/fanotify/fanotify.c:813 [inline]
fanotify_handle_event+0x1130/0x3f40 fs/notify/fanotify/fanotify.c:948
send_to_group fs/notify/fsnotify.c:360 [inline]
fsnotify+0xafb/0x1680 fs/notify/fsnotify.c:570
__fsnotify_parent+0x62f/0xa60 fs/notify/fsnotify.c:230
fsnotify_parent include/linux/fsnotify.h:77 [inline]
fsnotify_file include/linux/fsnotify.h:99 [inline]
fsnotify_access include/linux/fsnotify.h:309 [inline]
__io_complete_rw_common+0x485/0x720 io_uring/rw.c:195
io_complete_rw+0x1a/0x1f0 io_uring/rw.c:228
iomap_dio_complete_work fs/iomap/direct-io.c:144 [inline]
iomap_dio_bio_end_io+0x438/0x5e0 fs/iomap/direct-io.c:178
bio_endio+0x5f9/0x780 block/bio.c:1564
req_bio_endio block/blk-mq.c:695 [inline]
blk_update_request+0x3fc/0x1300 block/blk-mq.c:825
scsi_end_request+0x7a/0x9a0 drivers/scsi/scsi_lib.c:541
scsi_io_completion+0x173/0x1f70 drivers/scsi/scsi_lib.c:971
scsi_complete+0x122/0x3b0 drivers/scsi/scsi_lib.c:1438
blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022
__do_softirq+0x1d3/0x9c6 kernel/softirq.c:571
invoke_softirq kernel/softirq.c:445 [inline]
__irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
common_interrupt+0xa9/0xc0 arch/x86/kernel/irq.c:240
Fixes: f63cf5192fe3 ("io_uring: ensure that fsnotify is always called")
Link: https://lore.kernel.org/all/20220929135627.ykivmdks2w5vzrwg@quack3/
Reported-by: syzbot+dfcc5f4da15868df7d4d@xxxxxxxxxxxxxxxxxxxxxxxxx
Reported-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 73d261004c4a..78ed38d778f8 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2705,12 +2705,6 @@ static bool io_rw_should_reissue(struct io_kiocb *req)
static bool __io_complete_rw_common(struct io_kiocb *req, long res)
{
- if (req->rw.kiocb.ki_flags & IOCB_WRITE) {
- kiocb_end_write(req);
- fsnotify_modify(req->file);
- } else {
- fsnotify_access(req->file);
- }
if (res != req->result) {
if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
io_rw_should_reissue(req)) {
@@ -2763,6 +2757,20 @@ static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
__io_req_complete(req, issue_flags, io_fixup_rw_res(req, res), io_put_rw_kbuf(req));
}
+static void io_req_rw_complete(struct io_kiocb *req, bool *locked)
+{
+ struct io_rw *rw = &req->rw;
+
+ if (rw->kiocb.ki_flags & IOCB_WRITE) {
+ kiocb_end_write(req);
+ fsnotify_modify(req->file);
+ } else {
+ fsnotify_access(req->file);
+ }
+
+ io_req_task_complete(req, locked);
+}
+
static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
@@ -2770,7 +2778,7 @@ static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
if (__io_complete_rw_common(req, res))
return;
req->result = io_fixup_rw_res(req, res);
- req->io_task_work.func = io_req_task_complete;
+ req->io_task_work.func = io_req_rw_complete;
io_req_task_work_add(req);
}
