2272 Commits
Author SHA1 Message Date
Pavel Begunkov ebae09bce4 io_uring/zcrx: use better name for RQ region
Rename "region" to "rq_region" to highlight that it's a refill queue
region.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/ac815790d2477a15826aecaa3d94f2a94ef507e6.1774261953.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-01 10:21:12 -06:00
Pavel Begunkov 825f276491 io_uring/zcrx: implement device-less mode for zcrx
Allow creating a zcrx instance without attaching it to a net device.
All data will be copied through the fallback path. The user is also
expected to use ZCRX_CTRL_FLUSH_RQ to handle overflows as it normally
should even with a netdev, but it becomes even more relevant as there
will likely be no one to automatically pick up buffers.

Apart from that, it follows the zcrx uapi for the I/O path, and is
useful for testing, experimentation, and potentially for the copy
receive path in the future if improved.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/674f8ad679c5a0bc79d538352b3042cf0999596e.1774261953.git.asml.silence@gmail.com
[axboe: fix spelling error in uapi header and commit message]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-01 10:21:12 -06:00
Pavel Begunkov 06fc3b6d38 io_uring/zcrx: extract netdev+area init into a helper
In preparation to following patches, add a function that is responsibly
for looking up a netdev, creating an area, DMA mapping it and opening a
queue.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/88cb6f746ecb496a9030756125419df273d0b003.1774261953.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-01 10:21:12 -06:00
Pavel Begunkov b8d6eb6c1c io_uring/zcrx: always dma map in advance
zcrx was originally establisihing dma mappings at a late stage when it
was being bound to a page pool. Dma-buf couldn't work this way, so it's
initialised during area creation.

It's messy having them do it at different spots, just move everything to
the area creation time.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/334092a2cbdd4aabd7c025050aa99f05ace89bb5.1774261953.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-01 10:21:12 -06:00
Pavel Begunkov 41041562a7 io_uring/zcrx: fully clean area on error in io_import_umem()
When accounting fails, io_import_umem() sets the page array, etc. and
returns an error expecting that the error handling code will take care
of the rest. To make the next patch simpler, only return a fully
initialised areas from the function.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/3a602b7fb347dbd4da6797ac49b52ea5dedb856d.1774261953.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-01 10:21:12 -06:00
Pavel Begunkov e5361d25e2 io_uring/zcrx: return back two step unregistration
There are reports where io_uring instance removal takes too long and an
ifq reallocation by another zcrx instance fails. Split zcrx destruction
into two steps similarly how it was before, first close the queue early
but maintain zcrx alive, and then when all inflight requests are
completed, drop the main zcrx reference. For extra protection, mark
terminated zcrx instances in xarray and warn if we double put them.

Cc: stable@vger.kernel.org # 6.19+
Link: https://github.com/axboe/liburing/issues/1550
Reported-by: Youngmin Choi <youngminchoi94@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/0ce21f0565ab4358668922a28a8a36922dfebf76.1774261953.git.asml.silence@gmail.com
[axboe: NULL ifq before break inside scoped guard]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-01 10:21:12 -06:00
Jens Axboe aa35dd6bdd io_uring/bpf_filters: retain COW'ed settings on parse failures
If io_parse_restrictions() fails, it ends up clearing any restrictions
currently set. The intent is only to clear whatever it already applied,
but it ends up clearing everything, including whatever settings may have
been applied in a copy-on-write fashion already. Ensure that those are
retained.

Link: https://lore.kernel.org/io-uring/CAK8a0jzF-zaO5ZmdOrmfuxrhXuKg5m5+RDuO7tNvtj=kUYbW7Q@mail.gmail.com/
Reported-by: antonius <bluedragonsec2023@gmail.com>
Fixes: ed82f35b92 ("io_uring: allow registration of per-task restrictions")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-01 08:34:14 -06:00
Jens Axboe 61a11cf481 io_uring: protect remaining lockless ctx->rings accesses with RCU
Commit 9618908026 addressed one case of ctx->rings being potentially
accessed while a resize is happening on the ring, but there are still
a few others that need handling. Add a helper for retrieving the
rings associated with an io_uring context, and add some sanity checking
to that to catch bad uses. ->rings_rcu is always valid, as long as it's
used within RCU read lock. Any use of ->rings_rcu or ->rings inside
either ->uring_lock or ->completion_lock is sane as well.

Do the minimum fix for the current kernel, but set it up such that this
basic infra can be extended for later kernels to make this harder to
mess up in the future.

Thanks to Junxi Qian for finding and debugging this issue.

Cc: stable@vger.kernel.org
Fixes: 79cfe9e59c ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS")
Reviewed-by: Junxi Qian <qjx1298677004@gmail.com>
Tested-by: Junxi Qian <qjx1298677004@gmail.com>
Link: https://lore.kernel.org/io-uring/20260330172348.89416-1-qjx1298677004@gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-01 08:34:11 -06:00
Qi Tang 111a12b422 io_uring/rsrc: reject zero-length fixed buffer import
validate_fixed_range() admits buf_addr at the exact end of the
registered region when len is zero, because the check uses strict
greater-than (buf_end > imu->ubuf + imu->len).  io_import_fixed()
then computes offset == imu->len, which causes the bvec skip logic
to advance past the last bio_vec entry and read bv_offset from
out-of-bounds slab memory.

Return early from io_import_fixed() when len is zero.  A zero-length
import has no data to transfer and should not walk the bvec array
at all.

  BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0
  Read of size 4 at addr ffff888002bcc254 by task poc/103
  Call Trace:
   io_import_reg_buf+0x697/0x7f0
   io_write_fixed+0xd9/0x250
   __io_issue_sqe+0xad/0x710
   io_issue_sqe+0x7d/0x1100
   io_submit_sqes+0x86a/0x23c0
   __do_sys_io_uring_enter+0xa98/0x1590
  Allocated by task 103:
  The buggy address is located 12 bytes to the right of
   allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)

Fixes: 8622b20f23 ("io_uring: add validate_fixed_range() for validate fixed buffer")
Signed-off-by: Qi Tang <tpluszz77@gmail.com>
Link: https://patch.msgid.link/20260329164936.240871-1-tpluszz77@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-29 14:03:55 -06:00
Junxi Qian b948f9d5d3 io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()
sqe->len is __u32 but gets stored into sr->len which is int. When
userspace passes sqe->len values exceeding INT_MAX (e.g. 0xFFFFFFFF),
sr->len overflows to a negative value. This negative value propagates
through the bundle recv/send path:

  1. io_recv(): sel.val = sr->len (ssize_t gets -1)
  2. io_recv_buf_select(): arg.max_len = sel->val (size_t gets
     0xFFFFFFFFFFFFFFFF)
  3. io_ring_buffers_peek(): buf->len is not clamped because max_len
     is astronomically large
  4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs()
  5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1,
     causing ret to increase instead of decrease, creating an
     infinite loop that reads past the allocated iov[] array

This results in a slab-out-of-bounds read in io_bundle_nbufs() from
the kmalloc-64 slab, as nbufs increments past the allocated iovec
entries.

  BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160
  Read of size 8 at addr ffff888100ae05c8 by task exp/145
  Call Trace:
   io_bundle_nbufs+0x128/0x160
   io_recv_finish+0x117/0xe20
   io_recv+0x2db/0x1160

Fix this by rejecting negative sr->len values early in both
io_sendmsg_prep() and io_recvmsg_prep(). Since sqe->len is __u32,
any value > INT_MAX indicates overflow and is not a valid length.

Fixes: a05d1f625c ("io_uring/net: support bundles for send")
Cc: stable@vger.kernel.org
Signed-off-by: Junxi Qian <qjx1298677004@gmail.com>
Link: https://patch.msgid.link/20260329153909.279046-1-qjx1298677004@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-29 14:03:14 -06:00
Linus Torvalds 196ef74abd Merge tag 'io_uring-7.0-20260327' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux
Pull io_uring fixes from Jens Axboe:
 "Just two small fixes, both fixing regressions added in the fdinfo code
  in 6.19 with the SQE mixed size support"

* tag 'io_uring-7.0-20260327' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
  io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check
  io_uring/fdinfo: fix SQE_MIXED SQE displaying
2026-03-27 15:35:38 -07:00
Nicholas Carlini 5170efd9c3 io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check
__io_uring_show_fdinfo() iterates over pending SQEs and, for 128-byte
SQEs on an IORING_SETUP_SQE_MIXED ring, needs to detect when the second
half of the SQE would be past the end of the sq_sqes array. The current
check tests (++sq_head & sq_mask) == 0, but sq_head is only incremented
when a 128-byte SQE is encountered, not on every iteration. The actual
array index is sq_idx = (i + sq_head) & sq_mask, which can be sq_mask
(the last slot) while the wrap check passes.

Fix by checking sq_idx directly. Keep the sq_head increment so the loop
still skips the second half of the 128-byte SQE on the next iteration.

Fixes: 1cba30bf9f ("io_uring: add support for IORING_SETUP_SQE_MIXED")
Signed-off-by: Nicholas Carlini <nicholas@carlini.com>
Link: https://patch.msgid.link/20260327021823.3138396-1-nicholas@carlini.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-26 20:28:28 -06:00
Jens Axboe b59efde9e6 io_uring/fdinfo: fix SQE_MIXED SQE displaying
When displaying pending SQEs for a MIXED ring, each 128-byte SQE
increments sq_head to skip the second slot, but the loop counter is not
adjusted. This can cause the loop to read past sq_tail by one entry for
each 128-byte SQE encountered, displaying SQEs that haven't been made
consumable yet by the application.

Match the kernel's own consumption logic in io_init_req() which
decrements what's left when consuming the extra slot.

Fixes: 1cba30bf9f ("io_uring: add support for IORING_SETUP_SQE_MIXED")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-26 07:15:55 -06:00
Christoph Hellwig 0924f6b80d fs: pass on FTRUNCATE_* flags to do_truncate
Pass the flags one level down to replace the somewhat confusing small
argument, and clean up do_truncate as a result.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260323070205.2939118-3-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-03-23 12:41:57 +01:00
Linus Torvalds c612261bed Merge tag 'io_uring-7.0-20260320' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux
Pull io_uring fixes from Jens Axboe:

 - A bit of a work-around for AF_UNIX recv multishot, as the in-kernel
   implementation doesn't properly signal EOF. We'll likely rework this
   one going forward, but the fix is sufficient for now

 - Two fixes for incrementally consumed buffers, for non-pollable files
   and for 0 byte reads

* tag 'io_uring-7.0-20260320' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
  io_uring/kbuf: propagate BUF_MORE through early buffer commit path
  io_uring/kbuf: fix missing BUF_MORE for incremental buffers at EOF
  io_uring/poll: fix multishot recv missing EOF on wakeup race
2026-03-20 09:58:56 -07:00
Jens Axboe 418eab7a6f io_uring/kbuf: propagate BUF_MORE through early buffer commit path
When io_should_commit() returns true (eg for non-pollable files), buffer
commit happens at buffer selection time and sel->buf_list is set to
NULL. When __io_put_kbufs() generates CQE flags at completion time, it
calls __io_put_kbuf_ring() which finds a NULL buffer_list and hence
cannot determine whether the buffer was consumed or not. This means that
IORING_CQE_F_BUF_MORE is never set for non-pollable input with
incrementally consumed buffers.

Likewise for io_buffers_select(), which always commits upfront and
discards the return value of io_kbuf_commit().

Add REQ_F_BUF_MORE to store the result of io_kbuf_commit() during early
commit. Then __io_put_kbuf_ring() can check this flag and set
IORING_F_BUF_MORE accordingy.

Reported-by: Martin Michaelis <code@mgjm.de>
Cc: stable@vger.kernel.org
Fixes: ae98dbf43d ("io_uring/kbuf: add support for incremental buffer consumption")
Link: https://github.com/axboe/liburing/issues/1553
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-19 15:09:48 -06:00
Jens Axboe 3ecd3e0314 io_uring/kbuf: fix missing BUF_MORE for incremental buffers at EOF
For a zero length transfer, io_kbuf_inc_commit() is called with !len.
Since we never enter the while loop to consume the buffers,
io_kbuf_inc_commit() ends up returning true, consuming the buffer. But
if no data was consumed, by definition it cannot have consumed the
buffer. Return false for that case.

Reported-by: Martin Michaelis <code@mgjm.de>
Cc: stable@vger.kernel.org
Fixes: ae98dbf43d ("io_uring/kbuf: add support for incremental buffer consumption")
Link: https://github.com/axboe/liburing/issues/1553
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-19 15:09:40 -06:00
Jens Axboe f41b075492 io_uring: avoid req->ctx reload in io_req_put_rsrc_nodes()
Cache 'ctx' to avoid it needing to get potentially reloaded.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17 14:35:00 -06:00
Jens Axboe 3e97c2582f io_uring/rw: use cached file rather than req->file
In io_rw_init_file(), req->file is cached in file, yet the former is
still being used when checking for O_DIRECT. As this is post setting
the kiocb flags, the compiler has to reload req->file. Just use the
locally cached file instead.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17 14:35:00 -06:00
Jens Axboe 0a6b9ae1f3 io_uring/net: use 'ctx' consistently
There's already a local ctx variable, use it for the io_is_compat()
check as well.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17 14:35:00 -06:00
Jens Axboe 74dbc0bab5 io_uring/poll: cache req->apoll_events
Avoid a potential reload of ->apoll_events post vfs_poll() by caching it
in a local variable.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17 14:34:51 -06:00
Jens Axboe 49c21d9a5f io_uring/kbuf: use 'ctx' consistently
There's already a local ctx variable, yet the ring lock and unlock
helpers use req->ctx. use ctx consistently.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17 14:03:54 -06:00
Jens Axboe a68ed2df72 io_uring/poll: fix multishot recv missing EOF on wakeup race
When a socket send and shutdown() happen back-to-back, both fire
wake-ups before the receiver's task_work has a chance to run. The first
wake gets poll ownership (poll_refs=1), and the second bumps it to 2.
When io_poll_check_events() runs, it calls io_poll_issue() which does a
recv that reads the data and returns IOU_RETRY. The loop then drains all
accumulated refs (atomic_sub_return(2) -> 0) and exits, even though only
the first event was consumed. Since the shutdown is a persistent state
change, no further wakeups will happen, and the multishot recv can hang
forever.

Check specifically for HUP in the poll loop, and ensure that another
loop is done to check for status if more than a single poll activation
is pending. This ensures we don't lose the shutdown event.

Cc: stable@vger.kernel.org
Fixes: dbc2564cfe ("io_uring: let fast poll support multishot")
Reported-by: Francis Brosseau <francis@malagauche.com>
Link: https://github.com/axboe/liburing/issues/1549
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17 13:54:08 -06:00
Pavel Begunkov 98f37634b1 io_uring/bpf-ops: implement bpf ops registration
Implement BPF struct ops registration. It's registered off the BPF
path, and can be removed by BPF as well as io_uring. To protect it,
introduce a global lock synchronising registration. ctx->uring_lock can
be nested under it. ctx->bpf_ops is write protected by both locks and
so it's safe to read it under either of them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/1f46bffd76008de49cbafa2ad77d348810a4f69e.1772109579.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 16:15:00 -06:00
Pavel Begunkov 890819248a io_uring/bpf-ops: add kfunc helpers
Add two kfuncs that should cover most of the needs:

1. bpf_io_uring_submit_sqes(), which allows to submit io_uring requests.
   It mirrors the normal user space submission path and follows all
   related io_uring_enter(2) rules. i.e. SQEs are taken from the SQ
   according to head/tail values. In case of IORING_SETUP_SQ_REWIND,
   it'll submit first N entries.

2. bpf_io_uring_get_region() returns a pointer to the specified region,
   where io_uring regions are kernel-userspace shared chunks of memory.
   It takes the size as an argument, which should be a load time
   constant. There are 3 types of regions:
   - IOU_REGION_SQ returns the submission queue.
   - IOU_REGION_CQ stores the CQ, SQ/CQ headers and the sqarray. In
     other words, it gives same memory that would normally be mmap'ed
     with IORING_FEAT_SINGLE_MMAP enabled IORING_OFF_SQ_RING.
   - IOU_REGION_MEM represents the memory / parameter region. It can be
     used to store request indirect parameters and for kernel - user
     communication.

It intentionally provides a thin but flexible API and expects BPF
programs to implement CQ/SQ header parsing, CQ walking, etc. That
mirrors how the normal user space works with rings and should help
to minimise kernel / kfunc helpers changes while introducing new generic
io_uring features.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/967bcc10e94c796eb273998621551b2a21848cde.1772109579.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 16:15:00 -06:00
Pavel Begunkov d0e437b76b io_uring/bpf-ops: implement loop_step with BPF struct_ops
Introduce io_uring BPF struct ops implementing the loop_step callback,
which will allow BPF to overwrite the default io_uring event loop logic.

The callback takes an io_uring context, the main role of which is to be
passed to io_uring kfuncs. The other argument is a struct iou_loop_params,
which BPF can use to request CQ waiting and communicate other parameters.
See the event loop description in the previous patch for more details.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/98db437651ce64e9cbeb611c60bf5887259db09f.1772109579.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 16:15:00 -06:00
Pavel Begunkov 033af2b3eb io_uring: introduce callback driven main loop
The io_uring_enter() has a fixed order of execution: it submits
requests, waits for completions, and returns to the user. Allow to
optionally replace it with a custom loop driven by a callback called
loop_step. The basic requirements to the callback is that it should be
able to submit requests, wait for completions, parse them and repeat.
Most of the communication including parameter passing can be implemented
via shared memory.

The callback should return IOU_LOOP_CONTINUE to continue execution or
IOU_LOOP_STOP to return to the user space. Note that the kernel may
decide to prematurely terminate it as well, e.g. in case the process was
signalled or killed.

The hook takes a structure with parameters. It can be used to ask the
kernel to wait for CQEs by setting cq_wait_idx to the CQE index it wants
to wait for. Spurious wake ups are possible and even likely, the callback
is expected to handle it. There will be more parameters in the future
like timeout.

It can be used with kernel callbacks, for example, as a slow path
deprecation mechanism overwiting SQEs and emulating the wanted
behaviour, however it's more useful together with BPF programs
implemented in following patches.

Note that keeping it separately from the normal io_uring wait loop
makes things much simpler and cleaner. It keeps it in one place instead
of spreading a bunch of checks in different places including disabling
the submission path. It holds the lock by default, which is a better fit
for BPF synchronisation and the loop execution model. It nicely avoids
existing quirks like forced wake ups on timeout request completion. And
it should be easier to implement new features.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://patch.msgid.link/a2d369aa1c9dd23ad7edac9220cffc563abcaed6.1772109579.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 16:15:00 -06:00
Caleb Sander Mateos 23475637b0 io_uring/uring_cmd: allow non-iopoll cmds with IORING_SETUP_IOPOLL
Currently, creating an io_uring with IORING_SETUP_IOPOLL requires all
requests issued to it to support iopoll. This prevents, for example,
using ublk zero-copy together with IORING_SETUP_IOPOLL, as ublk
zero-copy buffer registrations are performed using a uring_cmd. There's
no technical reason why these non-iopoll uring_cmds can't be supported.
They will either complete synchronously or via an external mechanism
that calls io_uring_cmd_done(), io_uring_cmd_post_mshot_cqe32(), or
io_uring_mshot_cmd_post_cqe(), so they don't need to be polled.

Allow uring_cmd requests to be issued to IORING_SETUP_IOPOLL io_urings
even if their files don't implement ->uring_cmd_iopoll(). For these
uring_cmd requests, skip initializing struct io_kiocb's iopoll fields,
don't set REQ_F_IOPOLL, and don't set IO_URING_F_IOPOLL in issue_flags.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://patch.msgid.link/20260302172914.2488599-5-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 16:14:14 -06:00
Caleb Sander Mateos 3a5e96d47f io_uring: count CQEs in io_iopoll_check()
A subsequent commit will allow uring_cmds that don't use iopoll on
IORING_SETUP_IOPOLL io_urings. As a result, CQEs can be posted without
setting the iopoll_completed flag for a request in iopoll_list or going
through task work. For example, a UBLK_U_IO_FETCH_IO_CMDS command could
call io_uring_mshot_cmd_post_cqe() to directly post a CQE. The
io_iopoll_check() loop currently only counts completions posted in
io_do_iopoll() when determining whether the min_events threshold has
been met. It also exits early if there are any existing CQEs before
polling, or if any CQEs are posted while running task work. CQEs posted
via io_uring_mshot_cmd_post_cqe() or other mechanisms won't be counted
against min_events.

Explicitly check the available CQEs in each io_iopoll_check() loop
iteration to account for CQEs posted in any fashion.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://patch.msgid.link/20260302172914.2488599-4-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 16:14:14 -06:00
Caleb Sander Mateos 7995be40de io_uring: remove iopoll_queue from struct io_issue_def
The opcode iopoll_queue flag is now redundant with REQ_F_IOPOLL. Only
io_{read,write}{,_fixed}() and io_uring_cmd() set the REQ_F_IOPOLL flag,
and the opcodes with these ->issue() implementations are precisely the
ones that set iopoll_queue. So don't bother checking the iopoll_queue
flag in io_issue_sqe(). Remove the unused flag from struct io_issue_def.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://patch.msgid.link/20260302172914.2488599-3-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 16:14:14 -06:00
Caleb Sander Mateos 9165dc4fa9 io_uring: add REQ_F_IOPOLL
A subsequent commit will allow uring_cmds to files that don't implement
->uring_cmd_iopoll() to be issued to IORING_SETUP_IOPOLL io_urings. This
means the ctx's IORING_SETUP_IOPOLL flag isn't sufficient to determine
whether a given request needs to be iopolled.

Introduce a request flag REQ_F_IOPOLL set in ->issue() if a request
needs to be iopolled to completion. Set the flag in io_rw_init_file()
and io_uring_cmd() for requests issued to IORING_SETUP_IOPOLL ctxs. Use
the request flag instead of IORING_SETUP_IOPOLL in places dealing with a
specific request.

A future possibility would be to add an option to enable/disable iopoll
in the io_uring SQE instead of determining it from IORING_SETUP_IOPOLL.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://patch.msgid.link/20260302172914.2488599-2-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 16:14:14 -06:00
Jens Axboe 8c55744919 io_uring: mark known and harmless racy ctx->int_flags uses
There are a few of these, where flags are read outside of the
uring_lock, yet it's harmless to race on them.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 15:33:10 -06:00
Jens Axboe f1a424e21c io_uring: switch struct io_ring_ctx internal bitfields to flags
Bitfields cannot be set and checked atomically, and this makes it more
clear that these are indeed in shared storage and must be checked and
set in a sane fashion. This is in preparation for annotating a few of
the known racy, but harmless, flags checking.

No intended functional changes in this patch.

Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-16 15:32:59 -06:00
Jens Axboe 0e46cb553f Merge branch 'io_uring-7.0' into for-7.1/io_uring
Merge upstream io_uring fixes to avoid conflicts in later patches.

* io_uring-7.0:
  io_uring/kbuf: check if target buffer list is still legacy on recycle
  io_uring: fix physical SQE bounds check for SQE_MIXED 128-byte ops
  io_uring/eventfd: use ctx->rings_rcu for flags checking
  io_uring: ensure ctx->rings is stable for task work flags manipulation
  io_uring/bpf_filter: use bpf_prog_run_pin_on_cpu() to prevent migration
  io_uring/register: fix comment about task_no_new_privs
2026-03-14 08:57:15 -06:00
Linus Torvalds e67bf352a0 Merge tag 'io_uring-7.0-20260312' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux
Pull io_uring fixes from Jens Axboe:

 - Fix an inverted true/false comment on task_no_new_privs, from the
   BPF filtering changes merged in this release

 - Use the migration disabling way of running the BPF filters, as the
   io_uring side doesn't do that already

 - Fix an issue with ->rings stability under resize, both for local
   task_work additions and for eventfd signaling

 - Fix an issue with SQE mixed mode, where a bounds check wasn't correct
   for having a 128b SQE

 - Fix an issue where a legacy provided buffer group is changed to to
   ring mapped one while legacy buffers from that group are in flight

* tag 'io_uring-7.0-20260312' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
  io_uring/kbuf: check if target buffer list is still legacy on recycle
  io_uring: fix physical SQE bounds check for SQE_MIXED 128-byte ops
  io_uring/eventfd: use ctx->rings_rcu for flags checking
  io_uring: ensure ctx->rings is stable for task work flags manipulation
  io_uring/bpf_filter: use bpf_prog_run_pin_on_cpu() to prevent migration
  io_uring/register: fix comment about task_no_new_privs
2026-03-13 10:09:35 -07:00
Jens Axboe c2c185be5c io_uring/kbuf: check if target buffer list is still legacy on recycle
There's a gap between when the buffer was grabbed and when it
potentially gets recycled, where if the list is empty, someone could've
upgraded it to a ring provided type. This can happen if the request
is forced via io-wq. The legacy recycling is missing checking if the
buffer_list still exists, and if it's of the correct type. Add those
checks.

Cc: stable@vger.kernel.org
Fixes: c7fb19428d ("io_uring: add support for ring mapped supplied buffers")
Reported-by: Keenan Dong <keenanat2000@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-12 08:59:25 -06:00
Tom Ryan 6f02c6b196 io_uring: fix physical SQE bounds check for SQE_MIXED 128-byte ops
When IORING_SETUP_SQE_MIXED is used without IORING_SETUP_NO_SQARRAY,
the boundary check for 128-byte SQE operations in io_init_req()
validated the logical SQ head position rather than the physical SQE
index.

The existing check:

  !(ctx->cached_sq_head & (ctx->sq_entries - 1))

ensures the logical position isn't at the end of the ring, which is
correct for NO_SQARRAY rings where physical == logical. However, when
sq_array is present, an unprivileged user can remap any logical
position to an arbitrary physical index via sq_array. Setting
sq_array[N] = sq_entries - 1 places a 128-byte operation at the last
physical SQE slot, causing the 128-byte memcpy in
io_uring_cmd_sqe_copy() to read 64 bytes past the end of the SQE
array.

Replace the cached_sq_head alignment check with a direct validation
of the physical SQE index, which correctly handles both sq_array and
NO_SQARRAY cases.

Fixes: 1cba30bf9f ("io_uring: add support for IORING_SETUP_SQE_MIXED")
Signed-off-by: Tom Ryan <ryan36005@gmail.com>
Link: https://patch.msgid.link/20260310052003.72871-1-ryan36005@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-11 14:35:19 -06:00
Jens Axboe 177c694321 io_uring/eventfd: use ctx->rings_rcu for flags checking
Similarly to what commit e78f7b70e837 did for local task work additions,
use ->rings_rcu under RCU rather than dereference ->rings directly. See
that commit for more details.

Cc: stable@vger.kernel.org
Fixes: 79cfe9e59c ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-11 14:35:19 -06:00
Jens Axboe 9618908026 io_uring: ensure ctx->rings is stable for task work flags manipulation
If DEFER_TASKRUN | SETUP_TASKRUN is used and task work is added while
the ring is being resized, it's possible for the OR'ing of
IORING_SQ_TASKRUN to happen in the small window of swapping into the
new rings and the old rings being freed.

Prevent this by adding a 2nd ->rings pointer, ->rings_rcu, which is
protected by RCU. The task work flags manipulation is inside RCU
already, and if the resize ring freeing is done post an RCU synchronize,
then there's no need to add locking to the fast path of task work
additions.

Note: this is only done for DEFER_TASKRUN, as that's the only setup mode
that supports ring resizing. If this ever changes, then they too need to
use the io_ctx_mark_taskrun() helper.

Link: https://lore.kernel.org/io-uring/20260309062759.482210-1-naup96721@gmail.com/
Cc: stable@vger.kernel.org
Fixes: 79cfe9e59c ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS")
Reported-by: Hao-Yu Yang <naup96721@gmail.com>
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-11 14:35:16 -06:00
Jens Axboe 785d4625d3 io_uring/bpf_filter: use bpf_prog_run_pin_on_cpu() to prevent migration
Since the caller, __io_uring_run_bpf_filters(), doesn't prevent
migration, it should use the migration disabling variant for running
the BPF program.

Fixes: d42eb05e60 ("io_uring: add support for BPF filtering for opcode restrictions")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 14:20:14 -06:00
Jann Horn 3306a589e5 io_uring/register: fix comment about task_no_new_privs
The actual code is right, but the comment is the wrong way around.

Fixes: ed82f35b92 ("io_uring: allow registration of per-task restrictions")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 08:40:18 -06:00
Pavel Begunkov cb94873336 io_uring/zctx: separate notification user_data
People previously asked for the notification CQE to have a different
user_data value from the main request completion. It's useful to
separate buffer and request handling logic and avoid separately
refcounting the request.

Let the user pass the notification user_data in sqe->addr3. If zero,
it'll inherit sqe->user_data as before. It doesn't change the rules for
when the user can expect a notification CQE, and it should still check
the IORING_CQE_F_MORE flag.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:23:29 -06:00
Pavel Begunkov dce00c8303 io_uring/net: allow vectorised regbuf send zc
Enable IORING_SEND_VECTORIZED with registered buffers for
IORING_OP_SEND_ZC. Set IORING_SEND_VECTORIZED for all msg send requests
to differentiate if the vectorised version is expected.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:22:09 -06:00
Pavel Begunkov d8345a2190 io_uring/timeout: immediate timeout arg
One the things the user has always keep in mind is that any user
pointers they put into an SQE is not going to be read by the kernel
until submission happens, and the user has to ensure the pointee stays
alive until then. For example, snippet below will lead to UAF of the on
stack variable ts. Instead of passing the timeout value as a pointer
allow to store it immediately in the SQE. The user has to set a new flag
called IORING_TIMEOUT_IMMEDIATE_ARG, in which case sqe->addr for timeout
or sqe->addr2 for timeout update requests will be interpreted as a time
value in nanosecods.

void prep_timeout(struct io_uring_sqe *sqe) {
    struct __kernel_timespec ts = {...};
    prep_timeout(sqe, &ts);
}

void submit() {
    sqe = get_sqe();
    prep_timeout(sqe);
    io_uring_submit();
}

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:21:54 -06:00
Pavel Begunkov 0e78aa188c io_uring/timeout: migrate reqs from ts64 to ktime
It'll be more convenient for next patches to keep ktime in requests
instead of timespec64. Convert everything to ktime right after user
argument parsing at request prep time.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:21:54 -06:00
Pavel Begunkov 6e3f5943a4 io_uring/timeout: add helper for parsing user time
There is some duplication for timespec checks that can be deduplicated
with a new function, and it'll be extended in next patches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:21:54 -06:00
Pavel Begunkov 484ae637a3 io_uring/timeout: check unused sqe fields
Zero check unused SQE fields addr3 and pad2 for timeout and timeout
update requests. They're not needed now, but could be used sometime
in the future.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:21:54 -06:00
Pavel Begunkov dc156e0f1a io_uring/zcrx: declare some constants for query
Add constants for zcrx features and supported registration flags that
can be reused by the query code. I was going to add another registration
flag, and this patch helps to avoid duplication and keeps changes
specific to zcrx files.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:21:54 -06:00
Pavel Begunkov 403fec55bf io_uring/zctx: unify zerocopy issue variants
io_send_zc and io_sendmsg_zc started different but now the only real
difference between them is how registered buffers are imported and
which net helper we use. Avoid duplication and combine them into a
single function.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:21:54 -06:00
Pavel Begunkov 2f9965f5d5 io_uring/zctx: move vec regbuf import into io_send_zc_import
Unify send and sendmsg zerocopy paths for importing registered buffers
and make io_send_zc_import() responsible for that. It's a preparation
patch making the next change simpler.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 07:21:53 -06:00