Commit graph

393 commits

Author SHA1 Message Date
Pavel Begunkov
5611be6c3d io_uring/rsrc: use nospec'ed indexes
[ Upstream commit 953c37e066 ]

We use array_index_nospec() for registered buffer indexes, but don't use
it while poking into rsrc tags, fix that.

Fixes: 634d00df5e ("io_uring: add full-fledged dynamic buffers support")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f02fafc5a9c0dd69be2b0618c38831c078232ff0.1681395792.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-05-11 23:03:24 +09:00
Wojciech Lukowicz
ac48787f58 io_uring: fix memory leak when removing provided buffers
[ Upstream commit b4a72c0589 ]

When removing provided buffers, io_buffer structs are not being disposed
of, leading to a memory leak. They can't be freed individually, because
they are allocated in page-sized groups. They need to be added to some
free list instead, such as io_buffers_cache. All callers already hold
the lock protecting it, apart from when destroying buffers, so had to
extend the lock there.

Fixes: cc3cec8367 ("io_uring: speedup provided buffer handling")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13 16:55:31 +02:00
Wojciech Lukowicz
bd4081fa1c io_uring: fix return value when removing provided buffers
[ Upstream commit c0921e51da ]

When a request to remove buffers is submitted, and the given number to be
removed is larger than available in the specified buffer group, the
resulting CQE result will be the number of removed buffers + 1, which is
1 more than it should be.

Previously, the head was part of the list and it got removed after the
loop, so the increment was needed. Now, the head is not an element of
the list, so the increment shouldn't be there anymore.

Fixes: dbc7d452e7 ("io_uring: manage provided buffers strictly ordered")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13 16:55:31 +02:00
Pavel Begunkov
d67b3cdaca io_uring: fix poll/netmsg alloc caches
commit fd30d1cdcc upstream.

We increase cache->nr_cached when we free into the cache but don't
decrease when we take from it, so in some time we'll get an empty
cache with cache->nr_cached larger than IO_ALLOC_CACHE_MAX, that fails
io_alloc_cache_put() and effectively disables caching.

Fixes: 9b797a37c4 ("io_uring: add abstraction around apoll cache")
Cc: stable@vger.kernel.org
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>
2023-04-06 12:10:52 +02:00
Pavel Begunkov
ef329fa764 io_uring/rsrc: fix rogue rsrc node grabbing
commit 4ff0b50de8 upstream.

We should not be looking at ctx->rsrc_node and anyhow modifying the node
without holding uring_lock, grabbing references in such a way is not
safe either.

Cc: stable@vger.kernel.org
Fixes: 5106dd6e74 ("io_uring: propagate issue_flags state down to file assignment")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1202ede2d7bb90136e3482b2b84aad9ed483e5d6.1680098433.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:10:51 +02:00
Jens Axboe
3eb2138d46 io_uring/poll: clear single/double poll flags on poll arming
commit 005308f7bd upstream.

Unless we have at least one entry queued, then don't call into
io_poll_remove_entries(). Normally this isn't possible, but if we
retry poll then we can have ->nr_entries cleared again as we're
setting it up. If this happens for a poll retry, then we'll still have
at least REQ_F_SINGLE_POLL set. io_poll_remove_entries() then thinks
it has entries to remove.

Clear REQ_F_SINGLE_POLL and REQ_F_DOUBLE_POLL unconditionally when
arming a poll request.

Fixes: c16bda3759 ("io_uring/poll: allow some retries for poll triggering spuriously")
Cc: stable@vger.kernel.org
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:10:51 +02:00
Jens Axboe
e5da11825e block/io_uring: pass in issue_flags for uring_cmd task_work handling
commit 9d2789ac9d upstream.

io_uring_cmd_done() currently assumes that the uring_lock is held
when invoked, and while it generally is, this is not guaranteed.
Pass in the issue_flags associated with it, so that we have
IO_URING_F_UNLOCKED available to be able to lock the CQ ring
appropriately when completing events.

Cc: stable@vger.kernel.org
Fixes: ee692a21e9 ("fs,io_uring: add infrastructure for uring-cmd")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:10:51 +02:00
Savino Dicanosa
7b100a45dc io_uring/rsrc: fix null-ptr-deref in io_file_bitmap_get()
commit 02a4d923e4 upstream.

When fixed files are unregistered, file_alloc_end and alloc_hint
are not cleared. This can later cause a NULL pointer dereference in
io_file_bitmap_get() if auto index selection is enabled via
IORING_FILE_INDEX_ALLOC:

[    6.519129] BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
[    6.541468] RIP: 0010:_find_next_zero_bit+0x1a/0x70
[...]
[    6.560906] Call Trace:
[    6.561322]  <TASK>
[    6.561672]  io_file_bitmap_get+0x38/0x60
[    6.562281]  io_fixed_fd_install+0x63/0xb0
[    6.562851]  ? __pfx_io_socket+0x10/0x10
[    6.563396]  io_socket+0x93/0xf0
[    6.563855]  ? __pfx_io_socket+0x10/0x10
[    6.564411]  io_issue_sqe+0x5b/0x3d0
[    6.564914]  io_submit_sqes+0x1de/0x650
[    6.565452]  __do_sys_io_uring_enter+0x4fc/0xb20
[    6.566083]  ? __do_sys_io_uring_register+0x11e/0xd80
[    6.566779]  do_syscall_64+0x3c/0x90
[    6.567247]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
[...]

To fix the issue, set file alloc range and alloc_hint to zero after
file tables are freed.

Cc: stable@vger.kernel.org
Fixes: 4278a0deb1 ("io_uring: defer alloc_hint update to io_file_bitmap_set()")
Signed-off-by: Savino Dicanosa <sd7.dev@pm.me>
[axboe: add explicit bitmap == NULL check as well]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30 12:49:25 +02:00
Jens Axboe
87f2d329f4 io_uring/net: avoid sending -ECONNABORTED on repeated connection requests
commit 74e2e17ee1 upstream.

Since io_uring does nonblocking connect requests, if we do two repeated
ones without having a listener, the second will get -ECONNABORTED rather
than the expected -ECONNREFUSED. Treat -ECONNABORTED like a normal retry
condition if we're nonblocking, if we haven't already seen it.

Cc: stable@vger.kernel.org
Fixes: 3fb1bd6881 ("io_uring/net: handle -EINPROGRESS correct for IORING_OP_CONNECT")
Link: https://github.com/axboe/liburing/issues/828
Reported-by: Hui, Chunyang <sanqian.hcy@antgroup.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30 12:49:25 +02:00
Pavel Begunkov
36773a78b0 io_uring/msg_ring: let target know allocated index
commit 5da28edd7b upstream.

msg_ring requests transferring files support auto index selection via
IORING_FILE_INDEX_ALLOC, however they don't return the selected index
to the target ring and there is no other good way for the userspace to
know where is the receieved file.

Return the index for allocated slots and 0 otherwise, which is
consistent with other fixed file installing requests.

Cc: stable@vger.kernel.org # v6.0+
Fixes: e6130eba8a ("io_uring: add support for passing fixed file descriptors")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://github.com/axboe/liburing/issues/809
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-22 13:34:06 +01:00
Jens Axboe
da8fab32a7 io_uring/uring_cmd: ensure that device supports IOPOLL
commit 03b3d6be73 upstream.

It's possible for a file type to support uring commands, but not
pollable ones. Hence before issuing one of those, we should check
that it is supported and error out upfront if it isn't.

Cc: stable@vger.kernel.org
Fixes: 5756a3a7e7 ("io_uring: add iopoll infrastructure for io_uring_cmd")
Link: https://github.com/axboe/liburing/issues/816
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-17 08:50:14 +01:00
Jens Axboe
c6b9c79c3d io_uring/poll: allow some retries for poll triggering spuriously
commit c16bda3759 upstream.

If we get woken spuriously when polling and fail the operation with
-EAGAIN again, then we generally only allow polling again if data
had been transferred at some point. This is indicated with
REQ_F_PARTIAL_IO. However, if the spurious poll triggers when the socket
was originally empty, then we haven't transferred data yet and we will
fail the poll re-arm. This either punts the socket to io-wq if it's
blocking, or it fails the request with -EAGAIN if not. Neither condition
is desirable, as the former will slow things down, while the latter
will make the application confused.

We want to ensure that a repeated poll trigger doesn't lead to infinite
work making no progress, that's what the REQ_F_PARTIAL_IO check was
for. But it doesn't protect against a loop post the first receive, and
it's unnecessarily strict if we started out with an empty socket.

Add a somewhat random retry count, just to put an upper limit on the
potential number of retries that will be done. This should be high enough
that we won't really hit it in practice, unless something needs to be
aborted anyway.

Cc: stable@vger.kernel.org # v5.10+
Link: https://github.com/axboe/liburing/issues/364
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-11 13:55:43 +01:00
Xinghui Li
3453b1b043 io_uring: fix two assignments in if conditions
commit df730ec21f upstream.

Fixes two errors:

"ERROR: do not use assignment in if condition
130: FILE: io_uring/net.c:130:
+       if (!(issue_flags & IO_URING_F_UNLOCKED) &&

ERROR: do not use assignment in if condition
599: FILE: io_uring/poll.c:599:
+       } else if (!(issue_flags & IO_URING_F_UNLOCKED) &&"
reported by checkpatch.pl in net.c and poll.c .

Signed-off-by: Xinghui Li <korantli@tencent.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20221102082503.32236-1-korantwork@gmail.com
[axboe: style tweaks]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-11 13:55:43 +01:00
Wojciech Lukowicz
b0498e95ca io_uring: fix size calculation when registering buf ring
[ Upstream commit 48ba08374e ]

Using struct_size() to calculate the size of io_uring_buf_ring will sum
the size of the struct and of the bufs array. However, the struct's fields
are overlaid with the array making the calculated size larger than it
should be.

When registering a ring with N * PAGE_SIZE / sizeof(struct io_uring_buf)
entries, i.e. with fully filled pages, the calculated size will span one
more page than it should and io_uring will try to pin the following page.
Depending on how the application allocated the ring, it might succeed
using an unrelated page or fail returning EFAULT.

The size of the ring should be the product of ring_entries and the size
of io_uring_buf, i.e. the size of the bufs array only.

Fixes: c7fb19428d ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20230218184141.70891-1-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-11 13:55:30 +01:00
Jens Axboe
55c9ddf6c6 io_uring: mark task TASK_RUNNING before handling resume/task work
commit 2f2bb1ffc9 upstream.

Just like for task_work, set the task mode to TASK_RUNNING before doing
any potential resume work. We're not holding any locks at this point,
but we may have already set the task state to TASK_INTERRUPTIBLE in
preparation for going to sleep waiting for events. Ensure that we set it
back to TASK_RUNNING if we have work to process, to avoid warnings on
calling blocking operations with !TASK_RUNNING.

Fixes: b5d3ae202f ("io_uring: handle TIF_NOTIFY_RESUME when checking for task_work")
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202302062208.24d3e563-oliver.sang@intel.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:07 +01:00
Joseph Qi
75a499fc9d io_uring: fix fget leak when fs don't support nowait buffered read
commit 54aa7f2330 upstream.

Heming reported a BUG when using io_uring doing link-cp on ocfs2. [1]

Do the following steps can reproduce this BUG:
mount -t ocfs2 /dev/vdc /mnt/ocfs2
cp testfile /mnt/ocfs2/
./link-cp /mnt/ocfs2/testfile /mnt/ocfs2/testfile.1
umount /mnt/ocfs2

Then umount will fail, and it outputs:
umount: /mnt/ocfs2: target is busy.

While tracing umount, it blames mnt_get_count() not return as expected.
Do a deep investigation for fget()/fput() on related code flow, I've
finally found that fget() leaks since ocfs2 doesn't support nowait
buffered read.

io_issue_sqe
|-io_assign_file  // do fget() first
  |-io_read
  |-io_iter_do_read
    |-ocfs2_file_read_iter  // return -EOPNOTSUPP
  |-kiocb_done
    |-io_rw_done
      |-__io_complete_rw_common  // set REQ_F_REISSUE
    |-io_resubmit_prep
      |-io_req_prep_async  // override req->file, leak happens

This was introduced by commit a196c78b54 in v5.18. Fix it by don't
re-assign req->file if it has already been assigned.

[1] https://lore.kernel.org/ocfs2-devel/ab580a75-91c8-d68a-3455-40361be1bfa8@linux.alibaba.com/T/#t

Fixes: a196c78b54 ("io_uring: assign non-fixed early for async work")
Cc: <stable@vger.kernel.org>
Reported-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230228045459.13524-1-joseph.qi@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:04 +01:00
David Lamparter
bfdd27a1eb io_uring: remove MSG_NOSIGNAL from recvmsg
commit 7605c43d67 upstream.

MSG_NOSIGNAL is not applicable for the receiving side, SIGPIPE is
generated when trying to write to a "broken pipe".  AF_PACKET's
packet_recvmsg() does enforce this, giving back EINVAL when MSG_NOSIGNAL
is set - making it unuseable in io_uring's recvmsg.

Remove MSG_NOSIGNAL from io_recvmsg_prep().

Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: David Lamparter <equinox@diac24.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230224150123.128346-1-equinox@diac24.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:04 +01:00
Pavel Begunkov
68f703ad03 io_uring/rsrc: disallow multi-source reg buffers
commit edd4782696 upstream.

If two or more mappings go back to back to each other they can be passed
into io_uring to be registered as a single registered buffer. That would
even work if mappings came from different sources, e.g. it's possible to
mix in this way anon pages and pages from shmem or hugetlb. That is not
a problem but it'd rather be less prone if we forbid such mixing.

Cc: <stable@vger.kernel.org>
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>
2023-03-10 09:34:04 +01:00
Jens Axboe
d9399e5430 io_uring: add reschedule point to handle_tw_list()
commit f586800854 upstream.

If CONFIG_PREEMPT_NONE is set and the task_work chains are long, we
could be running into issues blocking others for too long. Add a
reschedule check in handle_tw_list(), and flush the ctx if we need to
reschedule.

Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:03 +01:00
Jens Axboe
42fe280e26 io_uring: add a conditional reschedule to the IOPOLL cancelation loop
commit fcc926bb85 upstream.

If the kernel is configured with CONFIG_PREEMPT_NONE, we could be
sitting in a tight loop reaping events but not giving them a chance to
finish. This results in a trace ala:

rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 	2-...!: (5249 ticks this GP) idle=935c/1/0x4000000000000000 softirq=4265/4274 fqs=1
	(t=5251 jiffies g=465 q=4135 ncpus=4)
rcu: rcu_sched kthread starved for 5249 jiffies! g465 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_sched       state:R  running task     stack:0     pid:12    ppid:2      flags:0x00000008
Call trace:
 __switch_to+0xb0/0xc8
 __schedule+0x43c/0x520
 schedule+0x4c/0x98
 schedule_timeout+0xbc/0xdc
 rcu_gp_fqs_loop+0x308/0x344
 rcu_gp_kthread+0xd8/0xf0
 kthread+0xb8/0xc8
 ret_from_fork+0x10/0x20
rcu: Stack dump where RCU GP kthread last ran:
Task dump for CPU 0:
task:kworker/u8:10   state:R  running task     stack:0     pid:89    ppid:2      flags:0x0000000a
Workqueue: events_unbound io_ring_exit_work
Call trace:
 __switch_to+0xb0/0xc8
 0xffff0000c8fefd28
CPU: 2 PID: 95 Comm: kworker/u8:13 Not tainted 6.2.0-rc5-00042-g40316e337c80-dirty #2759
Hardware name: linux,dummy-virt (DT)
Workqueue: events_unbound io_ring_exit_work
pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : io_do_iopoll+0x344/0x360
lr : io_do_iopoll+0xb8/0x360
sp : ffff800009bebc60
x29: ffff800009bebc60 x28: 0000000000000000 x27: 0000000000000000
x26: ffff0000c0f67d48 x25: ffff0000c0f67840 x24: ffff800008950024
x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c27d3200
x20: ffff0000c0f67840 x19: ffff0000c0f67800 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
x14: 0000000000000001 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000179 x10: 0000000000000870 x9 : ffff800009bebd60
x8 : ffff0000c27d3ad0 x7 : fefefefefefefeff x6 : 0000646e756f626e
x5 : ffff0000c0f67840 x4 : 0000000000000000 x3 : ffff0000c2398000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 io_do_iopoll+0x344/0x360
 io_uring_try_cancel_requests+0x21c/0x334
 io_ring_exit_work+0x90/0x40c
 process_one_work+0x1a4/0x254
 worker_thread+0x1ec/0x258
 kthread+0xb8/0xc8
 ret_from_fork+0x10/0x20

Add a cond_resched() in the cancelation IOPOLL loop to fix this.

Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:03 +01:00
Jens Axboe
4c13c6a080 io_uring: handle TIF_NOTIFY_RESUME when checking for task_work
commit b5d3ae202f upstream.

If TIF_NOTIFY_RESUME is set, then we need to call resume_user_mode_work()
for PF_IO_WORKER threads. They never return to usermode, hence never get
a chance to process any items that are marked by this flag. Most notably
this includes the final put of files, but also any throttling markers set
by block cgroups.

Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:03 +01:00
Pavel Begunkov
c981a035df io_uring: use user visible tail in io_uring_poll()
commit c10bb64684 upstream.

We return POLLIN from io_uring_poll() depending on whether there are
CQEs for the userspace, and so we should use the user visible tail
pointer instead of a transient cached value.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/228ffcbf30ba98856f66ffdb9a6a60ead1dd96c0.1674484266.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:03 +01:00
Al Viro
5a19095103 use less confusing names for iov_iter direction initializers
[ Upstream commit de4eda9de2 ]

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Stable-dep-of: 6dd88fd59d ("vhost-scsi: unbreak any layout for response")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-09 11:28:04 +01:00
Dylan Yudaken
5e6618e28b io_uring: always prep_async for drain requests
[ Upstream commit ef5c600adb ]

Drain requests all go through io_drain_req, which has a quick exit in case
there is nothing pending (ie the drain is not useful). In that case it can
run the issue the request immediately.

However for safety it queues it through task work.
The problem is that in this case the request is run asynchronously, but
the async work has not been prepared through io_req_prep_async.

This has not been a problem up to now, as the task work always would run
before returning to userspace, and so the user would not have a chance to
race with it.

However - with IORING_SETUP_DEFER_TASKRUN - this is no longer the case and
the work might be defered, giving userspace a chance to change data being
referred to in the request.

Instead _always_ prep_async for drain requests, which is simpler anyway
and removes this issue.

Cc: stable@vger.kernel.org
Fixes: c0e0d6ba25 ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
Signed-off-by: Dylan Yudaken <dylany@meta.com>
Link: https://lore.kernel.org/r/20230127105911.2420061-1-dylany@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:42 +01:00
Pavel Begunkov
1ce29f7444 io_uring: inline __io_req_complete_put()
[ Upstream commit fa18fa2272 ]

Inline __io_req_complete_put() into io_req_complete_post(), there are no
other users.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1923a4dfe80fa877f859a22ed3df2d5fc8ecf02b.1669203009.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: ef5c600adb ("io_uring: always prep_async for drain requests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:41 +01:00
Pavel Begunkov
85224a3f89 io_uring: remove io_req_tw_post_queue
[ Upstream commit 833b5dfffc ]

Remove io_req_tw_post() and io_req_tw_post_queue(), we can use
io_req_task_complete() instead.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b9b73c08022c7f1457023ac841f35c0100e70345.1669203009.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: ef5c600adb ("io_uring: always prep_async for drain requests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:41 +01:00
Pavel Begunkov
65aeb34c0f io_uring: use io_req_task_complete() in timeout
[ Upstream commit 624fd779fd ]

Use a more generic io_req_task_complete() in timeout completion
task_work instead of io_req_complete_post().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bda1710b58c07bf06107421c2a65c529ea9cdcac.1669203009.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: ef5c600adb ("io_uring: always prep_async for drain requests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:41 +01:00
Pavel Begunkov
0c4d95ad21 io_uring: hold locks for io_req_complete_failed
[ Upstream commit e276ae344a ]

A preparation patch, make sure we always hold uring_lock around
io_req_complete_failed(). The only place deviating from the rule
is io_cancel_defer_files(), queue a tw instead.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/70760344eadaecf2939287084b9d4ba5c05a6984.1669203009.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: ef5c600adb ("io_uring: always prep_async for drain requests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:41 +01:00
Pavel Begunkov
6dbb84c7c2 io_uring: inline __io_req_complete_post()
[ Upstream commit f9d567c75e ]

There is only one user of __io_req_complete_post(), inline it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ef4c9059950a3da5cf68df00f977f1fd13bd9306.1668597569.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: ef5c600adb ("io_uring: always prep_async for drain requests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:41 +01:00
Pavel Begunkov
bfd4d18840 io_uring: inline io_req_task_work_add()
[ Upstream commit e52d2e583e ]

__io_req_task_work_add() is huge but marked inline, that makes compilers
to generate lots of garbage. Inline the wrapper caller
io_req_task_work_add() instead.

before and after:
   text    data     bss     dec     hex filename
  47347   16248       8   63603    f873 io_uring/io_uring.o
   text    data     bss     dec     hex filename
  45303   16248       8   61559    f077 io_uring/io_uring.o

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/26dc8c28ca0160e3269ef3e55c5a8b917c4d4450.1668162751.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: ef5c600adb ("io_uring: always prep_async for drain requests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:41 +01:00
Jens Axboe
121d87eb58 io_uring/net: cache provided buffer group value for multishot receives
commit b00c51ef8f upstream.

If we're using ring provided buffers with multishot receive, and we end
up doing an io-wq based issue at some points that also needs to select
a buffer, we'll lose the initially assigned buffer group as
io_ring_buffer_select() correctly clears the buffer group list as the
issue isn't serialized by the ctx uring_lock. This is fine for normal
receives as the request puts the buffer and finishes, but for multishot,
we will re-arm and do further receives. On the next trigger for this
multishot receive, the receive will try and pick from a buffer group
whose value is the same as the buffer ID of the las receive. That is
obviously incorrect, and will result in a premature -ENOUFS error for
the receive even if we had available buffers in the correct group.

Cache the buffer group value at prep time, so we can restore it for
future receives. This only needs doing for the above mentioned case, but
just do it by default to keep it easier to read.

Cc: stable@vger.kernel.org
Fixes: b3fdea6ecb ("io_uring: multishot recv")
Fixes: 9bb66906f2 ("io_uring: support multishot in recvmsg")
Cc: Dylan Yudaken <dylany@meta.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-01 08:34:38 +01:00
Pavel Begunkov
c932501bc2 io_uring/msg_ring: fix remote queue to disabled ring
commit 8579538c89 upstream.

IORING_SETUP_R_DISABLED rings don't have the submitter task set, so
it's not always safe to use ->submitter_task. Disallow posting msg_ring
messaged to disabled rings. Also add task NULL check for loosy sync
around testing for IORING_SETUP_R_DISABLED.

Cc: stable@vger.kernel.org
Fixes: 6d043ee116 ("io_uring: do msg_ring in target task via tw")
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>
2023-02-01 08:34:35 +01:00
Jens Axboe
36fc7317cd io_uring/poll: don't reissue in case of poll race on multishot request
commit 8caa03f10b upstream.

A previous commit fixed a poll race that can occur, but it's only
applicable for multishot requests. For a multishot request, we can safely
ignore a spurious wakeup, as we never leave the waitqueue to begin with.

A blunt reissue of a multishot armed request can cause us to leak a
buffer, if they are ring provided. While this seems like a bug in itself,
it's not really defined behavior to reissue a multishot request directly.
It's less efficient to do so as well, and not required to rearm anything
like it is for singleshot poll requests.

Cc: stable@vger.kernel.org
Fixes: 6e5aedb932 ("io_uring/poll: attempt request issue after racy poll wakeup")
Reported-and-tested-by: Olivier Langlois <olivier@trillion01.com>
Link: https://github.com/axboe/liburing/issues/778
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:37 +01:00
Jens Axboe
e62e6258ab io_uring/io-wq: only free worker if it was allocated for creation
commit e6db6f9398 upstream.

We have two types of task_work based creation, one is using an existing
worker to setup a new one (eg when going to sleep and we have no free
workers), and the other is allocating a new worker. Only the latter
should be freed when we cancel task_work creation for a new worker.

Fixes: af82425c6a ("io_uring/io-wq: free worker if task_work creation is canceled")
Reported-by: syzbot+d56ec896af3637bdb7e4@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:58:33 +01:00
Jens Axboe
0a14c3ded8 io_uring/io-wq: free worker if task_work creation is canceled
commit af82425c6a upstream.

If we cancel the task_work, the worker will never come into existance.
As this is the last reference to it, ensure that we get it freed
appropriately.

Cc: stable@vger.kernel.org
Reported-by: 진호 <wnwlsgh98@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:58:33 +01:00
Jens Axboe
c06015ebc4 io_uring/poll: attempt request issue after racy poll wakeup
commit 6e5aedb932 upstream.

If we have multiple requests waiting on the same target poll waitqueue,
then it's quite possible to get a request triggered and get disappointed
in not being able to make any progress with it. If we race in doing so,
we'll potentially leave the poll request on the internal tables, but
removed from the waitqueue. That means that any subsequent trigger of
the poll waitqueue will not kick that request into action, causing an
application to potentially wait for completion of a request that will
never happen.

Fix this by adding a new poll return state, IOU_POLL_REISSUE. Rather
than have complicated logic for how to re-arm a given type of request,
just punt it for a reissue.

While in there, move the 'ret' variable to the only section where it
gets used. This avoids confusion the scope of it.

Cc: stable@vger.kernel.org
Fixes: eb0089d629 ("io_uring: single shot poll removal optimisation")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-18 11:58:33 +01:00
Pavel Begunkov
7fc3990dad io_uring: lock overflowing for IOPOLL
commit 544d163d65 upstream.

syzbot reports an issue with overflow filling for IOPOLL:

WARNING: CPU: 0 PID: 28 at io_uring/io_uring.c:734 io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734
CPU: 0 PID: 28 Comm: kworker/u4:1 Not tainted 6.2.0-rc3-syzkaller-16369-g358a161a6a9e #0
Workqueue: events_unbound io_ring_exit_work
Call trace:
 io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734
 io_req_cqe_overflow+0x5c/0x70 io_uring/io_uring.c:773
 io_fill_cqe_req io_uring/io_uring.h:168 [inline]
 io_do_iopoll+0x474/0x62c io_uring/rw.c:1065
 io_iopoll_try_reap_events+0x6c/0x108 io_uring/io_uring.c:1513
 io_uring_try_cancel_requests+0x13c/0x258 io_uring/io_uring.c:3056
 io_ring_exit_work+0xec/0x390 io_uring/io_uring.c:2869
 process_one_work+0x2d8/0x504 kernel/workqueue.c:2289
 worker_thread+0x340/0x610 kernel/workqueue.c:2436
 kthread+0x12c/0x158 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863

There is no real problem for normal IOPOLL as flush is also called with
uring_lock taken, but it's getting more complicated for IOPOLL|SQPOLL,
for which __io_cqring_overflow_flush() happens from the CQ waiting path.

Reported-and-tested-by: syzbot+6805087452d72929404e@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-18 11:58:33 +01:00
Jens Axboe
617401df46 io_uring/fdinfo: include locked hash table in fdinfo output
commit ea97cbebaf upstream.

A previous commit split the hash table for polled requests into two
parts, but didn't get the fdinfo output updated. This means that it's
less useful for debugging, as we may think a given request is not pending
poll.

Fix this up by dumping the locked hash table contents too.

Fixes: 9ca9fb24d5 ("io_uring: mutex locked poll hashing")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:58:15 +01:00
Jens Axboe
4ad6c06354 io_uring/poll: add hash if ready poll request can't complete inline
commit febb985c06 upstream.

If we don't, then we may lose access to it completely, leading to a
request leak. This will eventually stall the ring exit process as
well.

Cc: stable@vger.kernel.org
Fixes: 49f1c68e04 ("io_uring: optimise submission side poll_refs")
Reported-and-tested-by: syzbot+6c95df01470a47fc3af4@syzkaller.appspotmail.com
Link: https://lore.kernel.org/io-uring/0000000000009f829805f1ce87b2@google.com/
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:58:10 +01:00
Pavel Begunkov
e595dcd987 io_uring: fix CQ waiting timeout handling
commit 12521a5d5c upstream.

Jiffy to ktime CQ waiting conversion broke how we treat timeouts, in
particular we rearm it anew every time we get into
io_cqring_wait_schedule() without adjusting the timeout. Waiting for 2
CQEs and getting a task_work in the middle may double the timeout value,
or even worse in some cases task may wait indefinitely.

Cc: stable@vger.kernel.org
Fixes: 228339662b ("io_uring: don't convert to jiffies for waiting on timeouts")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f7bffddd71b08f28a877d44d37ac953ddb01590d.1672915663.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-12 12:02:48 +01:00
Pavel Begunkov
91d1295199 io_uring: pin context while queueing deferred tw
commit 9ffa13ff78 upstream.

Unlike normal tw, nothing prevents deferred tw to be executed right
after an tw item added to ->work_llist in io_req_local_work_add(). For
instance, the waiting task may get waken up by CQ posting or a normal
tw. Thus we need to pin the ring for the rest of io_req_local_work_add()

Cc: stable@vger.kernel.org
Fixes: c0e0d6ba25 ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1a79362b9c10b8523ef70b061d96523650a23344.1672795998.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-12 12:02:48 +01:00
Jens Axboe
8b2de52126 io_uring: check for valid register opcode earlier
[ Upstream commit 343190841a ]

We only check the register opcode value inside the restricted ring
section, move it into the main io_uring_register() function instead
and check it up front.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-12 12:02:41 +01:00
Jens Axboe
a288e98adc io_uring/cancel: re-grab ctx mutex after finishing wait
[ Upstream commit 23fffb2f09 ]

If we have a signal pending during cancelations, it'll cause the
task_work run to return an error. Since we didn't run task_work, the
current task is left in TASK_INTERRUPTIBLE state when we need to
re-grab the ctx mutex, and the kernel will rightfully complain about
that.

Move the lock grabbing for the error cases outside the loop to avoid
that issue.

Reported-by: syzbot+7df055631cd1be4586fd@syzkaller.appspotmail.com
Link: https://lore.kernel.org/io-uring/0000000000003a14a905f05050b0@google.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-12 12:02:38 +01:00
Jens Axboe
ff46a46b7a io_uring: pass in EPOLL_URING_WAKE for eventfd signaling and wakeups
[ Upstream commit 4464853277 ]

Pass in EPOLL_URING_WAKE when signaling eventfd or doing poll related
wakups, so that we can check for a circular event dependency between
eventfd and epoll. If this flag is set when our wakeup handlers are
called, then we know we have a dependency that needs to terminate
multishot requests.

eventfd and epoll are the only such possible dependencies.

Cc: stable@vger.kernel.org # 6.0
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-04 11:28:48 +01:00
Pavel Begunkov
69c2ad94fd io_uring: remove iopoll spinlock
commit 2dac1a1592 upstream.

This reverts commit 2ccc92f4ef

io_req_complete_post() should now behave well even in case of IOPOLL, we
can remove completion_lock locking.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7e171c8b530656b14a671c59100ca260e46e7f2a.1669203009.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-31 13:33:12 +01:00
Pavel Begunkov
9b5d3f21f1 io_uring: protect cq_timeouts with timeout_lock
commit ea011ee102 upstream.

Read cq_timeouts in io_flush_timeouts() only after taking the
timeout_lock, as it's protected by it. There are many places where we
also grab ->completion_lock, but for instance io_timeout_fn() doesn't
and still modifies cq_timeouts.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9c79544dd6cf5c4018cb1bab99cf481a93ea46ef.1670002973.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-31 13:33:12 +01:00
Pavel Begunkov
f9ef51a705 io_uring/net: fix cleanup after recycle
commit 6c3e8955d4 upstream.

Don't access io_async_msghdr io_netmsg_recycle(), it may be reallocated.

Cc: stable@vger.kernel.org
Fixes: 9bb66906f2 ("io_uring: support multishot in recvmsg")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9e326f4ad4046ddadf15bf34bf3fa58c6372f6b5.1671461985.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-31 13:33:12 +01:00
Jens Axboe
b87006265a io_uring/net: ensure compat import handlers clear free_iov
commit 990a4de57e upstream.

If we're not allocating the vectors because the count is below
UIO_FASTIOV, we still do need to properly clear ->free_iov to prevent
an erronous free of on-stack data.

Reported-by: Jiri Slaby <jirislaby@gmail.com>
Fixes: 4c17a496a7 ("io_uring/net: fix cleanup double free free_iov init")
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-31 13:33:12 +01:00
Pavel Begunkov
e2c22a38fe io_uring: improve io_double_lock_ctx fail handling
commit 4c979eaefa upstream.

msg_ring will fail the request if it can't lock rings, instead punt it
to io-wq as was originally intended.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4697f05afcc37df5c8f89e2fe6d9c7c19f0241f9.1670384893.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-31 13:33:12 +01:00
Pavel Begunkov
f6a5cada4f io_uring: dont remove file from msg_ring reqs
commit ef0ec1ad03 upstream.

We should not be messing with req->file outside of core paths. Clearing
it makes msg_ring non reentrant, i.e. luckily io_msg_send_fd() fails the
request on failed io_double_lock_ctx() but clearly was originally
intended to do retries instead.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e5ac9edadb574fe33f6d727cb8f14ce68262a684.1670384893.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-31 13:33:12 +01:00