[ Upstream commit 22dbb0987b ]
By having them share the same space in struct io_cancel_data, it ends up
disallowing IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_USERDATA from
working. Eg you cannot match on both a file and user_data for
cancelation purposes. This obviously isn't a common use case as nobody
has reported this, but it does result in -ENOENT potentially being
returned when trying to match on both, rather than actually doing what
the API says it would.
Fixes: 4bf94615b8 ("io_uring: allow IORING_OP_ASYNC_CANCEL with 'fd' key")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 649dd18f55 ]
Check if the passed in offset is negative once cast to sync->off. This
ensures that -EINVAL is returned for that case, like it would be for
sync_file_range(2).
Fixes: c992fe2925 ("io_uring: add fsync support")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 10dc959398 upstream.
Currently this is checked before running the pending work. Normally this
is quite fine, as work items either end up blocking (which will create a
new worker for other items), or they complete fairly quickly. But syzbot
reports an issue where io-wq takes seemingly forever to exit, and with a
bit of debugging, this turns out to be because it queues a bunch of big
(2GB - 4096b) reads with a /dev/msr* file. Since this file type doesn't
support ->read_iter(), loop_rw_iter() ends up handling them. Each read
returns 16MB of data read, which takes 20 (!!) seconds. With a bunch of
these pending, processing the whole chain can take a long time. Easily
longer than the syzbot uninterruptible sleep timeout of 140 seconds.
This then triggers a complaint off the io-wq exit path:
INFO: task syz.4.135:6326 blocked for more than 143 seconds.
Not tainted syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.135 state:D stack:26824 pid:6326 tgid:6324 ppid:5957 task_flags:0x400548 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:121
io_wq_exit_workers io_uring/io-wq.c:1328 [inline]
io_wq_put_and_exit+0x271/0x8a0 io_uring/io-wq.c:1356
io_uring_clean_tctx+0x10d/0x190 io_uring/tctx.c:203
io_uring_cancel_generic+0x69c/0x9a0 io_uring/cancel.c:651
io_uring_files_cancel include/linux/io_uring.h:19 [inline]
do_exit+0x2ce/0x2bd0 kernel/exit.c:911
do_group_exit+0xd3/0x2a0 kernel/exit.c:1112
get_signal+0x2671/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x8c/0x540 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa02738f749
RSP: 002b:00007fa0281ae0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fa0275e6098 RCX: 00007fa02738f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa0275e6098
RBP: 00007fa0275e6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa0275e6128 R14: 00007fff14e4fcb0 R15: 00007fff14e4fd98
There's really nothing wrong here, outside of processing these reads
will take a LONG time. However, we can speed up the exit by checking the
IO_WQ_BIT_EXIT inside the io_worker_handle_work() loop, as syzbot will
exit the ring after queueing up all of these reads. Then once the first
item is processed, io-wq will simply cancel the rest. That should avoid
syzbot running into this complaint again.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/68a2decc.050a0220.e29e5.0099.GAE@google.com/
Reported-by: syzbot+4eb282331cab6d5b6588@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit da579f05ef upstream.
With IORING_SETUP_DEFER_TASKRUN, task work is queued to ctx->work_llist
(local work) rather than the fallback list. During io_ring_exit_work(),
io_move_task_work_from_local() was called once before the cancel loop,
moving work from work_llist to fallback_llist.
However, task work can be added to work_llist during the cancel loop
itself. There are two cases:
1) io_kill_timeouts() is called from io_uring_try_cancel_requests() to
cancel pending timeouts, and it adds task work via io_req_queue_tw_complete()
for each cancelled timeout:
2) URING_CMD requests like ublk can be completed via
io_uring_cmd_complete_in_task() from ublk_queue_rq() during canceling,
given ublk request queue is only quiesced when canceling the 1st uring_cmd.
Since io_allowed_defer_tw_run() returns false in io_ring_exit_work()
(kworker != submitter_task), io_run_local_work() is never invoked,
and the work_llist entries are never processed. This causes
io_uring_try_cancel_requests() to loop indefinitely, resulting in
100% CPU usage in kworker threads.
Fix this by moving io_move_task_work_from_local() inside the cancel
loop, ensuring any work on work_llist is moved to fallback before
each cancel attempt.
Cc: stable@vger.kernel.org
Fixes: c0e0d6ba25 ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 84230ad2d2 upstream.
When the core of io_uring was updated to handle completions
consistently and with fixed return codes, the POLL_REMOVE opcode
with updates got slightly broken. If a POLL_ADD is pending and
then POLL_REMOVE is used to update the events of that request, if that
update causes the POLL_ADD to now trigger, then that completion is lost
and a CQE is never posted.
Additionally, ensure that if an update does cause an existing POLL_ADD
to complete, that the completion value isn't always overwritten with
-ECANCELED. For that case, whatever io_poll_add() set the value to
should just be retained.
Cc: stable@vger.kernel.org
Fixes: 97b388d70b ("io_uring: handle completions in the core")
Reported-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com
Tested-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b14fad5553 upstream.
__io_openat_prep() allocates a struct filename using getname(). However,
for the condition of the file being installed in the fixed file table as
well as having O_CLOEXEC flag set, the function returns early. At that
point, the request doesn't have REQ_F_NEED_CLEANUP flag set. Due to this,
the memory for the newly allocated struct filename is not cleaned up,
causing a memory leak.
Fix this by setting the REQ_F_NEED_CLEANUP for the request just after the
successful getname() call, so that when the request is torn down, the
filename will be cleaned up, along with other resources needing cleanup.
Reported-by: syzbot+00e61c43eb5e4740438f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=00e61c43eb5e4740438f
Tested-by: syzbot+00e61c43eb5e4740438f@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Prithvi Tambewagh <activprithvi@gmail.com>
Fixes: b9445598d8 ("io_uring: openat directly into fixed fd table")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit c5efc6a0b3 ]
The __must_hold annotation references &req->ctx->uring_lock, but req
is not in scope in io_install_fixed_file. This change updates the
annotation to reference the correct ctx->uring_lock.
improving code clarity.
Fixes: f110ed8498 ("io_uring: split out fixed file installation and removal")
Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Commit 3539b1467e upstream.
When running task_work for an exiting task, rather than perform the
issue retry attempt, the task_work is canceled. However, this isn't
done for a ring that has been closed. This can lead to requests being
successfully completed post the ring being closed, which is somewhat
confusing and surprising to an application.
Rather than just check the task exit state, also include the ring
ref state in deciding whether or not to terminate a given request when
run from task_work.
Cc: stable@vger.kernel.org # 6.1+
Link: https://github.com/axboe/liburing/discussions/1459
Reported-by: Benedek Thaler <thaler@thaler.hu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Parts of commit b6f58a3f4a upstream.
Backport io_should_terminate_tw() helper to judge whether task_work
should be run or terminated.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 41b70df5b3 upstream.
Ring provided buffers are potentially only valid within the single
execution context in which they were acquired. io_uring deals with this
and invalidates them on retry. But on the networking side, if
MSG_WAITALL is set, or if the socket is of the streaming type and too
little was processed, then it will hang on to the buffer rather than
recycle or commit it. This is problematic for two reasons:
1) If someone unregisters the provided buffer ring before a later retry,
then the req->buf_list will no longer be valid.
2) If multiple sockers are using the same buffer group, then multiple
receives can consume the same memory. This can cause data corruption
in the application, as either receive could land in the same
userspace buffer.
Fix this by disallowing partial retries from pinning a provided buffer
across multiple executions, if ring provided buffers are used.
Cc: stable@vger.kernel.org
Reported-by: pt x <superman.xpt@gmail.com>
Fixes: c56e022c0a ("io_uring: add support for user mapped provided buffer ring")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c7cafd5b81 upstream.
8c8492ca64 ("io_uring/net: don't retry connect operation on EPOLLERR")
is a little dirty hack that
1) wrongfully assumes that POLLERR equals to a failed request, which
breaks all POLLERR users, e.g. all error queue recv interfaces.
2) deviates the connection request behaviour from connect(2), and
3) racy and solved at a wrong level.
Nothing can be done with 2) now, and 3) is beyond the scope of the
patch. At least solve 1) by moving the hack out of generic poll handling
into io_connect().
Cc: stable@vger.kernel.org
Fixes: 8c8492ca64 ("io_uring/net: don't retry connect operation on EPOLLERR")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3dc89036388d602ebd84c28e5042e457bdfc952b.1752682444.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit ae6a888a43 upstream.
A previous commit improved how !FMODE_NOWAIT is dealt with, but
inadvertently negated a check whilst doing so. This caused -EAGAIN to be
returned from reading files with O_NONBLOCK set. Fix up the check for
REQ_F_SUPPORT_NOWAIT.
Reported-by: Julian Orth <ju.orth@gmail.com>
Link: https://github.com/axboe/liburing/issues/1270
Fixes: f7c9134385 ("io_uring/rw: allow pollable non-blocking attempts for !FMODE_NOWAIT")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit f7c9134385 upstream.
The checking for whether or not io_uring can do a non-blocking read or
write attempt is gated on FMODE_NOWAIT. However, if the file is
pollable, it's feasible to just check if it's currently in a state in
which it can sanely receive or send _some_ data.
This avoids unnecessary io-wq punts, and repeated worthless retries
before doing that punt, by assuming that some data can get delivered
or received if poll tells us that is true. It also allows multishot
reads to properly work with these types of files, enabling a bit of
a cleanup of the logic that:
c9d952b910 ("io_uring/rw: fix cflags posting for single issue multishot read")
had to put in place.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 95041b93e9 upstream.
This adds a flag to avoid dipping dereferencing file and then f_op to
figure out if the file has a poll handler defined or not. We generally
call this at least twice for networked workloads, and if using ring
provided buffers, we do it on every buffer selection. Particularly the
latter is troublesome, as it's otherwise a very fast operation.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 687b2bae0e upstream.
Multishot normally uses io_req_post_cqe() to post completions, but when
stopping it, it may finish up with a deferred completion. This is fine,
except if another multishot event triggers before the deferred completions
get flushed. If this occurs, then CQEs may get reordered in the CQ ring,
and cause confusion on the application side.
When multishot posting via io_req_post_cqe(), flush any pending deferred
completions first, if any.
Cc: stable@vger.kernel.org # 6.1+
Reported-by: Norman Maurer <norman_maurer@apple.com>
Reported-by: Christian Mazakas <christian.mazakas@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit b53e523261 upstream.
There are a few spots where linked timeouts are armed, and not all of
them adhere to the pre-arm, attempt issue, post-arm pattern. This can
be problematic if the linked request returns that it will trigger a
callback later, and does so before the linked timeout is fully armed.
Consolidate all the linked timeout handling into __io_issue_sqe(),
rather than have it spread throughout the various issue entry points.
Cc: stable@vger.kernel.org
Link: https://github.com/axboe/liburing/issues/1390
Reported-by: Chase Hiltz <chase@path.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 390513642e ]
io_uring always switches requests to atomic refcounting for iowq
execution before there is any parallilism by setting REQ_F_REFCOUNT,
and the flag is not cleared until the request completes. That should be
fine as long as the compiler doesn't make up a non existing value for
the flags, however KCSAN still complains when the request owner changes
oter flag bits:
BUG: KCSAN: data-race in io_req_task_cancel / io_wq_free_work
...
read to 0xffff888117207448 of 8 bytes by task 3871 on cpu 0:
req_ref_put_and_test io_uring/refs.h:22 [inline]
Skip REQ_F_REFCOUNT checks for iowq, we know it's set.
Reported-by: syzbot+903a2ad71fb3f1e47cf5@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d880bc27fb8c3209b54641be4ff6ac02b0e5789a.1743679736.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit edd43f4d6f upstream.
A previous commit added a 'sync' parameter to io_fallback_tw(), which if
true, means the caller wants to wait on the fallback thread handling it.
But the logic is somewhat messed up, ensure that ctxs are swapped and
flushed appropriately.
Cc: stable@vger.kernel.org
Fixes: dfbe5561ae ("io_uring: flush offloaded and delayed task_work on exit")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 18595c0a58 upstream.
There are a few cases of open-rolled loops around unpin_user_page(), use
the generic helper instead.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 87585b0575 upstream.
Rather than use remap_pfn_range() for this and manually free later,
switch to using vm_insert_page() and have it Just Work.
This requires a bit of effort on the mmap lookup side, as the ctx
uring_lock isn't held, which otherwise protects buffer_lists from being
torn down, and it's not safe to grab from mmap context that would
introduce an ABBA deadlock between the mmap lock and the ctx uring_lock.
Instead, lookup the buffer_list under RCU, as the the list is RCU freed
already. Use the existing reference count to determine whether it's
possible to safely grab a reference to it (eg if it's not zero already),
and drop that reference when done with the mapping. If the mmap
reference is the last one, the buffer_list and the associated memory can
go away, since the vma insertion has references to the inserted pages at
that point.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit e270bfd22a upstream.
This avoids needing to care about HIGHMEM, and it makes the buffer
indexing easier as both ring provided buffer methods are now virtually
mapped in a contigious fashion.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 1943f96b38 upstream.
Move it into io_uring.c where it belongs, and use it in there as well
rather than have two implementations of this.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 09fc75e0c0 upstream.
This is the last holdout which does odd page checking, convert it to
vmap just like what is done for the non-mmap path.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 43eef70e7e upstream.
io_pages_unmap() is a bit tricky in trying to figure whether the pages
were previously vmap'ed or not. In particular If there is juts one page
it belives there is no need to vunmap. Paired io_pages_map(), however,
could've failed io_mem_alloc_compound() and attempted to
io_mem_alloc_single(), which does vmap, and that leads to unpaired vmap.
The solution is to fail if io_mem_alloc_compound() can't allocate a
single page. That's the easiest way to deal with it, and those two
functions are getting removed soon, so no need to overcomplicate it.
Cc: stable@vger.kernel.org
Fixes: 3ab1db3c60 ("io_uring: get rid of remap_pfn_range() for mapping rings/sqes")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/477e75a3907a2fe83249e49c0a92cd480b2c60e0.1732569842.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 06fe9b1df1 upstream.
If IORING_FEAT_SINGLE_MMAP is ignored, as can happen if an application
uses an ancient liburing or does setup manually, then 3 mmap's are
required to map the ring into userspace. The kernel will still have
collapsed the mappings, however userspace may ask for mapping them
individually. If so, then we should not use the full number of ring
pages, as it may exceed the partial mapping. Doing so will yield an
-EFAULT from vm_insert_pages(), as we pass in more pages than what the
application asked for.
Cap the number of pages to match what the application asked for, for
the particular mapping operation.
Reported-by: Lucas Mülling <lmulling@proton.me>
Link: https://github.com/axboe/liburing/issues/1157
Fixes: 3ab1db3c60 ("io_uring: get rid of remap_pfn_range() for mapping rings/sqes")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 3ab1db3c60 upstream.
Rather than use remap_pfn_range() for this and manually free later,
switch to using vm_insert_pages() and have it Just Work.
If possible, allocate a single compound page that covers the range that
is needed. If that works, then we can just use page_address() on that
page. If we fail to get a compound page, allocate single pages and use
vmap() to map them into the kernel virtual address space.
This just covers the rings/sqes, the other remaining user of the mmap
remap_pfn_range() user will be converted separately. Once that is done,
we can kill the old alloc/free code.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 13918315c5 ]
When io_uring submission goes async for the first time on a given task,
we'll try to create a worker thread to handle the submission. Creating
this worker thread can fail due to various transient conditions, such as
an outstanding signal in the forking thread, so we have retry logic with
a limit of 3 retries. However, this retry logic appears to be too
aggressive/fast - we've observed a thread blowing through the retry
limit while having the same outstanding signal the whole time. Here's an
excerpt of some tracing that demonstrates the issue:
First, signal 26 is generated for the process. It ends up getting routed
to thread 92942.
0) cbd-92284 /* signal_generate: sig=26 errno=0 code=-2 comm=psblkdASD pid=92934 grp=1 res=0 */
This causes create_io_thread in the signalled thread to fail with
ERESTARTNOINTR, and thus a retry is queued.
13) task_th-92942 /* io_uring_queue_async_work: ring 000000007325c9ae, request 0000000080c96d8e, user_data 0x0, opcode URING_CMD, flags 0x8240001, normal queue, work 000000006e96dd3f */
13) task_th-92942 io_wq_enqueue() {
13) task_th-92942 _raw_spin_lock();
13) task_th-92942 io_wq_activate_free_worker();
13) task_th-92942 _raw_spin_lock();
13) task_th-92942 create_io_worker() {
13) task_th-92942 __kmalloc_cache_noprof();
13) task_th-92942 __init_swait_queue_head();
13) task_th-92942 kprobe_ftrace_handler() {
13) task_th-92942 get_kprobe();
13) task_th-92942 aggr_pre_handler() {
13) task_th-92942 pre_handler_kretprobe();
13) task_th-92942 /* create_enter: (create_io_thread+0x0/0x50) fn=0xffffffff8172c0e0 arg=0xffff888996bb69c0 node=-1 */
13) task_th-92942 } /* aggr_pre_handler */
...
13) task_th-92942 } /* copy_process */
13) task_th-92942 } /* create_io_thread */
13) task_th-92942 kretprobe_rethook_handler() {
13) task_th-92942 /* create_exit: (create_io_worker+0x8a/0x1a0 <- create_io_thread) arg1=0xfffffffffffffdff */
13) task_th-92942 } /* kretprobe_rethook_handler */
13) task_th-92942 queue_work_on() {
...
The CPU is then handed to a kworker to process the queued retry:
------------------------------------------
13) task_th-92942 => kworker-54154
------------------------------------------
13) kworker-54154 io_workqueue_create() {
13) kworker-54154 io_queue_worker_create() {
13) kworker-54154 task_work_add() {
13) kworker-54154 wake_up_state() {
13) kworker-54154 try_to_wake_up() {
13) kworker-54154 _raw_spin_lock_irqsave();
13) kworker-54154 _raw_spin_unlock_irqrestore();
13) kworker-54154 } /* try_to_wake_up */
13) kworker-54154 } /* wake_up_state */
13) kworker-54154 kick_process();
13) kworker-54154 } /* task_work_add */
13) kworker-54154 } /* io_queue_worker_create */
13) kworker-54154 } /* io_workqueue_create */
And then we immediately switch back to the original task to try creating
a worker again. This fails, because the original task still hasn't
handled its signal.
-----------------------------------------
13) kworker-54154 => task_th-92942
------------------------------------------
13) task_th-92942 create_worker_cont() {
13) task_th-92942 kprobe_ftrace_handler() {
13) task_th-92942 get_kprobe();
13) task_th-92942 aggr_pre_handler() {
13) task_th-92942 pre_handler_kretprobe();
13) task_th-92942 /* create_enter: (create_io_thread+0x0/0x50) fn=0xffffffff8172c0e0 arg=0xffff888996bb69c0 node=-1 */
13) task_th-92942 } /* aggr_pre_handler */
13) task_th-92942 } /* kprobe_ftrace_handler */
13) task_th-92942 create_io_thread() {
13) task_th-92942 copy_process() {
13) task_th-92942 task_active_pid_ns();
13) task_th-92942 _raw_spin_lock_irq();
13) task_th-92942 recalc_sigpending();
13) task_th-92942 _raw_spin_lock_irq();
13) task_th-92942 } /* copy_process */
13) task_th-92942 } /* create_io_thread */
13) task_th-92942 kretprobe_rethook_handler() {
13) task_th-92942 /* create_exit: (create_worker_cont+0x35/0x1b0 <- create_io_thread) arg1=0xfffffffffffffdff */
13) task_th-92942 } /* kretprobe_rethook_handler */
13) task_th-92942 io_worker_release();
13) task_th-92942 queue_work_on() {
13) task_th-92942 clear_pending_if_disabled();
13) task_th-92942 __queue_work() {
13) task_th-92942 } /* __queue_work */
13) task_th-92942 } /* queue_work_on */
13) task_th-92942 } /* create_worker_cont */
The pattern repeats another couple times until we blow through the retry
counter, at which point we give up. All outstanding work is canceled,
and the io_uring command which triggered all this is failed with
ECANCELED:
13) task_th-92942 io_acct_cancel_pending_work() {
...
13) task_th-92942 /* io_uring_complete: ring 000000007325c9ae, req 0000000080c96d8e, user_data 0x0, result -125, cflags 0x0 extra1 0 extra2 0 */
Finally, the task gets around to processing its outstanding signal 26,
but it's too late.
13) task_th-92942 /* signal_deliver: sig=26 errno=0 code=-2 sa_handler=59566a0 sa_flags=14000000 */
Try to address this issue by adding a small scaling delay when retrying
worker creation. This should give the forking thread time to handle its
signal in the above case. This isn't a particularly satisfying solution,
as sufficiently paradoxical scheduling would still have us hitting the
same issue, and I'm open to suggestions for something better. But this
is likely to prevent this (already rare) issue from hitting in practice.
Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Link: https://lore.kernel.org/r/20250208-wq_retry-v2-1-4f6f5041d303@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 8802766324 upstream.
IORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it
was created for legacy selected buffer and has been emptied. It violates
the requirement that most of the field should stay stable after publish.
Always reallocate it instead.
Cc: stable@vger.kernel.org
Reported-by: Pumpkin Chang <pumpkin@devco.re>
Fixes: 2fcabce2d7 ("io_uring: disallow mixed provided buffer group registrations")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When we get -EIOCBQUEUED, we need to ensure that the buffer is consumed
from the provided buffer ring, which can be done with io_kbuf_recycle()
+ REQ_F_PARTIAL_IO.
Reported-by: Muhammad Ramdhan <ramdhan@starlabs.sg>
Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg>
Reported-by: Jacob Soo <jacob.soo@starlabs.sg>
Fixes: c7fb19428d ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_req_prep_async() can import provided buffers, commit the ring state
by giving up on that before, it'll be reimported later if needed.
Reported-by: Muhammad Ramdhan <ramdhan@starlabs.sg>
Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg>
Reported-by: Jacob Soo <jacob.soo@starlabs.sg>
Fixes: c7fb19428d ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8c8492ca64 upstream.
If a socket is shutdown before the connection completes, POLLERR is set
in the poll mask. However, connect ignores this as it doesn't know, and
attempts the connection again. This may lead to a bogus -ETIMEDOUT
result, where it should have noticed the POLLERR and just returned
-ECONNRESET instead.
Have the poll logic check for whether or not POLLERR is set in the mask,
and if so, mark the request as failed. Then connect can appropriately
fail the request rather than retry it.
Reported-by: Sergey Galas <ssgalas@cloud.ru>
Cc: stable@vger.kernel.org
Link: https://github.com/axboe/liburing/discussions/1335
Fixes: 3fb1bd6881 ("io_uring/net: handle -EINPROGRESS correct for IORING_OP_CONNECT")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit d58d82bd0e ]
io_uring_cmd_sock() does a normal read of cmd->sqe->cmd_op, where it
really should be using a READ_ONCE() as ->sqe may still be pointing to
the original SQE. Since the prep side already does this READ_ONCE() and
stores it locally, use that value rather than re-read it.
Fixes: 8e9fad0e70 ("io_uring: Add io_uring command support for sockets")
Link: https://lore.kernel.org/r/20250121-uring-sockcmd-fix-v1-1-add742802a29@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Commit c9a40292a4 upstream.
io_eventfd_do_signal() is invoked from an RCU callback, but when
dropping the reference to the io_ev_fd, it calls io_eventfd_free()
directly if the refcount drops to zero. This isn't correct, as any
potential freeing of the io_ev_fd should be deferred another RCU grace
period.
Just call io_eventfd_put() rather than open-code the dec-and-test and
free, which will correctly defer it another RCU grace period.
Fixes: 21a091b970 ("io_uring: signal registered eventfd to process deferred task work")
Reported-by: Jann Horn <jannh@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e33ac68e5e upstream.
BUG: KASAN: slab-use-after-free in __lock_acquire+0x370b/0x4a10 kernel/locking/lockdep.c:5089
Call Trace:
<TASK>
...
_raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162
class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
try_to_wake_up+0xb5/0x23c0 kernel/sched/core.c:4205
io_sq_thread_park+0xac/0xe0 io_uring/sqpoll.c:55
io_sq_thread_finish+0x6b/0x310 io_uring/sqpoll.c:96
io_sq_offload_create+0x162/0x11d0 io_uring/sqpoll.c:497
io_uring_create io_uring/io_uring.c:3724 [inline]
io_uring_setup+0x1728/0x3230 io_uring/io_uring.c:3806
...
Kun Hu reports that the SQPOLL creating error path has UAF, which
happens if io_uring_alloc_task_context() fails and then io_sq_thread()
manages to run and complete before the rest of error handling code,
which means io_sq_thread_finish() is looking at already killed task.
Note that this is mostly theoretical, requiring fault injection on
the allocation side to trigger in practice.
Cc: stable@vger.kernel.org
Reported-by: Kun Hu <huk23@m.fudan.edu.cn>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0f2f1aa5729332612bd01fe0f2f385fd1f06ce7c.1735231717.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit c0a9d496e0 upstream.
Some file systems, ocfs2 in this case, will return -EOPNOTSUPP for
an IOCB_NOWAIT read/write attempt. While this can be argued to be
correct, the usual return value for something that requires blocking
issue is -EAGAIN.
A refactoring io_uring commit dropped calling kiocb_done() for
negative return values, which is otherwise where we already do that
transformation. To ensure we catch it in both spots, check it in
__io_read() itself as well.
Reported-by: Robert Sander <r.sander@heinlein-support.de>
Link: https://fosstodon.org/@gurubert@mastodon.gurubert.de/113112431889638440
Cc: stable@vger.kernel.org
Fixes: a08d195b58 ("io_uring/rw: split io_read() into a helper")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
