linux-stable.git/io_uring, branch v6.9.5

io_uring: check for non-NULL file pointer in io_file_can_poll()

2024-06-16T11:51:04+00:00

commit 5fc16fa5f13b3c06fdb959ef262050bd810416a2 upstream.

In earlier kernels, it was possible to trigger a NULL pointer
dereference off the forced async preparation path, if no file had
been assigned. The trace leading to that looks as follows:

BUG: kernel NULL pointer dereference, address: 00000000000000b0
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 67 PID: 1633 Comm: buf-ring-invali Not tainted 6.8.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS unknown 2/2/2022
RIP: 0010:io_buffer_select+0xc3/0x210
Code: 00 00 48 39 d1 0f 82 ae 00 00 00 48 81 4b 48 00 00 01 00 48 89 73 70 0f b7 50 0c 66 89 53 42 85 ed 0f 85 d2 00 00 00 48 8b 13 <48> 8b 92 b0 00 00 00 48 83 7a 40 00 0f 84 21 01 00 00 4c 8b 20 5b
RSP: 0018:ffffb7bec38c7d88 EFLAGS: 00010246
RAX: ffff97af2be61000 RBX: ffff97af234f1700 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffff97aecfb04820 RDI: ffff97af234f1700
RBP: 0000000000000000 R08: 0000000000200030 R09: 0000000000000020
R10: ffffb7bec38c7dc8 R11: 000000000000c000 R12: ffffb7bec38c7db8
R13: ffff97aecfb05800 R14: ffff97aecfb05800 R15: ffff97af2be5e000
FS:  00007f852f74b740(0000) GS:ffff97b1eeec0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000b0 CR3: 000000016deab005 CR4: 0000000000370ef0
Call Trace:
 
 ? __die+0x1f/0x60
 ? page_fault_oops+0x14d/0x420
 ? do_user_addr_fault+0x61/0x6a0
 ? exc_page_fault+0x6c/0x150
 ? asm_exc_page_fault+0x22/0x30
 ? io_buffer_select+0xc3/0x210
 __io_import_iovec+0xb5/0x120
 io_readv_prep_async+0x36/0x70
 io_queue_sqe_fallback+0x20/0x260
 io_submit_sqes+0x314/0x630
 __do_sys_io_uring_enter+0x339/0xbc0
 ? __do_sys_io_uring_register+0x11b/0xc50
 ? vm_mmap_pgoff+0xce/0x160
 do_syscall_64+0x5f/0x180
 entry_SYSCALL_64_after_hwframe+0x46/0x4e
RIP: 0033:0x55e0a110a67e
Code: ba cc 00 00 00 45 31 c0 44 0f b6 92 d0 00 00 00 31 d2 41 b9 08 00 00 00 41 83 e2 01 41 c1 e2 04 41 09 c2 b8 aa 01 00 00 0f 05  90 89 30 eb a9 0f 1f 40 00 48 8b 42 20 8b 00 a8 06 75 af 85 f6

because the request is marked forced ASYNC and has a bad file fd, and
hence takes the forced async prep path.

Current kernels with the request async prep cleaned up can no longer hit
this issue, but for ease of backporting, let's add this safety check in
here too as it really doesn't hurt. For both cases, this will inevitably
end with a CQE posted with -EBADF.

Cc: stable@vger.kernel.org
Fixes: a76c0b31eef5 ("io_uring: commit non-pollable provided mapped buffers upfront")
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

io_uring/napi: fix timeout calculation

2024-06-16T11:51:04+00:00

commit 415ce0ea55c5a3afea501a773e002be9ed7149f5 upstream.

Not quite sure what __io_napi_adjust_timeout() was attemping to do, it's
adjusting both the NAPI timeout and the general overall timeout, and
calculating a value that is never used. The overall timeout is a super
set of the NAPI timeout, and doesn't need adjusting. The only thing we
really need to care about is that the NAPI timeout doesn't exceed the
overall timeout. If a user asked for a timeout of eg 5 usec and NAPI
timeout is 10 usec, then we should not spin for 10 usec.

While in there, sanitize the time checking a bit. If we have a negative
value in the passed in timeout, discard it. Round up the value as well,
so we don't end up with a NAPI timeout for the majority of the wait,
with only a tiny sleep value at the end.

Hence the only case we need to care about is if the NAPI timeout is
larger than the overall timeout. If it is, cap the NAPI timeout at what
the overall timeout is.

Cc: stable@vger.kernel.org
Fixes: 8d0c12a80cde ("io-uring: add napi busy poll support")
Reported-by: Lewis Baker 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

io_uring/net: fix sendzc lazy wake polling

2024-05-30T07:44:09+00:00

[ Upstream commit ef42b85a5609cd822ca0a68dd2bef2b12b5d1ca3 ]

SEND[MSG]_ZC produces multiple CQEs via notifications, LAZY_WAKE doesn't
handle it and so disable LAZY_WAKE for sendzc polling. It should be
fine, sends are not likely to be polled in the first place.

Fixes: 6ce4a93dbb5b ("io_uring/poll: use IOU_F_TWQ_LAZY_WAKE for wakeups")
Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/5b360fb352d91e3aec751d75c87dfb4753a084ee.1714488419.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

io-wq: write next_work before dropping acct_lock

2024-05-30T07:44:07+00:00

[ Upstream commit 068c27e32e51e94e4a9eb30ae85f4097a3602980 ]

Commit 361aee450c6e ("io-wq: add intermediate work step between pending
list and active work") closed a race between a cancellation and the work
being removed from the wq for execution.  To ensure the request is
always reachable by the cancellation, we need to move it within the wq
lock, which also synchronizes the cancellation.  But commit
42abc95f05bf ("io-wq: decouple work_list protection from the big
wqe->lock") replaced the wq lock here and accidentally reintroduced the
race by releasing the acct_lock too early.

In other words:

        worker                |     cancellation
work = io_get_next_work()     |
raw_spin_unlock(&acct->lock); |
			      |
                              | io_acct_cancel_pending_work
                              | io_wq_worker_cancel()
worker->next_work = work

Using acct_lock is still enough since we synchronize on it on
io_acct_cancel_pending_work.

Fixes: 42abc95f05bf ("io-wq: decouple work_list protection from the big wqe->lock")
Signed-off-by: Gabriel Krisman Bertazi 
Link: https://lore.kernel.org/r/20240416021054.3940-2-krisman@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

io_uring: use the right type for work_llist empty check

2024-05-30T07:44:05+00:00

[ Upstream commit 22537c9f79417fed70b352d54d01d2586fee9521 ]

io_task_work_pending() uses wq_list_empty() on ctx->work_llist, but it's
not an io_wq_work_list, it's a struct llist_head. They both have
->first as head-of-list, and it turns out the checks are identical. But
be proper and use the right helper.

Fixes: dac6a0eae793 ("io_uring: ensure iopoll runs local task work as well")
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

io_uring/sqpoll: ensure that normal task_work is also run timely

2024-05-30T07:43:59+00:00

commit d13ddd9c893f0e8498526bf88c6b5fad01f0edd8 upstream.

With the move to private task_work, SQPOLL neglected to also run the
normal task_work, if any is pending. This will eventually get run, but
we should run it with the private task_work to ensure that things like
a final fput() is processed in a timely fashion.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/313824bc-799d-414f-96b7-e6de57c7e21d@gmail.com/
Reported-by: Andrew Udvare 
Fixes: af5d68f8892f ("io_uring/sqpoll: manage task_work privately")
Tested-by: Christian Heusel 
Tested-by: Andrew Udvare 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

io_uring: fail NOP if non-zero op flags is passed in

2024-05-30T07:43:59+00:00

commit 3d8f874bd620ce03f75a5512847586828ab86544 upstream.

The NOP op flags should have been checked from beginning like any other
opcode, otherwise NOP may not be extended with the op flags.

Given both liburing and Rust io-uring crate always zeros SQE op flags, just
ignore users which play raw NOP uring interface without zeroing SQE, because
NOP is just for test purpose. Then we can save one NOP2 opcode.

Suggested-by: Jens Axboe 
Fixes: 2b188cc1bb85 ("Add io_uring IO interface")
Cc: stable@vger.kernel.org
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20240510035031.78874-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

io_uring/net: restore msg_control on sendzc retry

2024-04-09T03:48:41+00:00

cac9e4418f4cb ("io_uring/net: save msghdr->msg_control for retries")
reinstatiates msg_control before every __sys_sendmsg_sock(), since the
function can overwrite the value in msghdr. We need to do same for
zerocopy sendmsg.

Cc: stable@vger.kernel.org
Fixes: 493108d95f146 ("io_uring/net: zerocopy sendmsg")
Link: https://github.com/axboe/liburing/issues/1067
Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/cc1d5d9df0576fa66ddad4420d240a98a020b267.1712596179.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

io_uring: Fix io_cqring_wait() not restoring sigmask on get_timespec64() failure

2024-04-06T02:05:41+00:00

This bug was introduced in commit 950e79dd7313 ("io_uring: minor
io_cqring_wait() optimization"), which was made in preparation for
adc8682ec690 ("io_uring: Add support for napi_busy_poll"). The latter
got reverted in cb3182167325 ("Revert "io_uring: Add support for
napi_busy_poll""), so simply undo the former as well.

Cc: stable@vger.kernel.org
Fixes: 950e79dd7313 ("io_uring: minor io_cqring_wait() optimization")
Signed-off-by: Alexey Izbyshev 
Link: https://lore.kernel.org/r/20240405125551.237142-1-izbyshev@ispras.ru
Signed-off-by: Jens Axboe

io_uring/kbuf: hold io_buffer_list reference over mmap

2024-04-03T01:03:27+00:00

If we look up the kbuf, ensure that it doesn't get unregistered until
after we're done with it. Since we're inside mmap, we cannot safely use
the io_uring lock. Rely on the fact that we can lookup the buffer list
under RCU now and grab a reference to it, preventing it from being
unregistered until we're done with it. The lookup returns the
io_buffer_list directly with it referenced.

Cc: stable@vger.kernel.org # v6.4+
Fixes: 5cf4f52e6d8a ("io_uring: free io_buffer_list entries via RCU")
Signed-off-by: Jens Axboe