Commit:
aacf2f9f38 ("io_uring: fix req->apoll_events")
fixed an issue where poll->events and req->apoll_events weren't
synchronized, but then when the commit referenced in Fixes got added,
it didn't ensure the same thing.
If we mask in EPOLLONESHOT in the regular EPOLL_URING_WAKE path, then
ensure it's done for both. Including a link to the original report
below, even though it's mostly nonsense. But it includes a reproducer
that does show that IORING_CQE_F_MORE is set in the previous CQE,
while no more CQEs will be generated for this request. Just ignore
anything that pretends this is security related in any way, it's just
the typical AI nonsense.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/io-uring/CAM0zi7yQzF3eKncgHo4iVM5yFLAjsiob_ucqyWKs=hyd_GqiMg@mail.gmail.com/
Reported-by: Azizcan Daştan <azizcan.d@mileniumsec.com>
Fixes: 4464853277 ("io_uring: pass in EPOLL_URING_WAKE for eventfd signaling and wakeups")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull io_uring updates from Jens Axboe:
- Add a callback driven main loop for io_uring, and BPF struct_ops
on top to allow implementing custom event loop logic
- Decouple IOPOLL from being a ring-wide all-or-nothing setting,
allowing IOPOLL use cases to also issue certain white listed
non-polled opcodes
- Timeout improvements. Migrate internal timeout storage from
timespec64 to ktime_t for simpler arithmetic and avoid copying of
timespec data
- Zero-copy receive (zcrx) updates:
- Add a device-less mode (ZCRX_REG_NODEV) for testing and
experimentation where data flows through the copy fallback path
- Fix two-step unregistration regression, DMA length calculations,
xarray mark usage, and a potential 32-bit overflow in id
shifting
- Refactoring toward multi-area support: dedicated refill queue
struct, consolidated DMA syncing, netmem array refilling format,
and guard-based locking
- Zero-copy transmit (zctx) cleanup:
- Unify io_send_zc() and io_sendmsg_zc() into a single function
- Add vectorized registered buffer send for IORING_OP_SEND_ZC
- Add separate notification user_data via sqe->addr3 so
notification and completion CQEs can be distinguished without
extra reference counting
- Switch struct io_ring_ctx internal bitfields to explicit flag bits
with atomic-safe accessors, and annotate the known harmless races on
those flags
- Various optimizations caching ctx and other request fields in local
variables to avoid repeated loads, and cleanups for tctx setup, ring
fd registration, and read path early returns
* tag 'for-7.1/io_uring-20260411' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (58 commits)
io_uring: unify getting ctx from passed in file descriptor
io_uring/register: don't get a reference to the registered ring fd
io_uring/tctx: clean up __io_uring_add_tctx_node() error handling
io_uring/tctx: have io_uring_alloc_task_context() return tctx
io_uring/timeout: use 'ctx' consistently
io_uring/rw: clean up __io_read() obsolete comment and early returns
io_uring/zcrx: use correct mmap off constants
io_uring/zcrx: use dma_len for chunk size calculation
io_uring/zcrx: don't clear not allocated niovs
io_uring/zcrx: don't use mark0 for allocating xarray
io_uring: cast id to u64 before shifting in io_allocate_rbuf_ring()
io_uring/zcrx: reject REG_NODEV with large rx_buf_size
io_uring/cancel: validate opcode for IORING_ASYNC_CANCEL_OP
io_uring/rsrc: use io_cache_free() to free node
io_uring/zcrx: rename zcrx [un]register functions
io_uring/zcrx: check ctrl op payload struct sizes
io_uring/zcrx: cache fallback availability in zcrx ctx
io_uring/zcrx: warn on a repeated area append
io_uring/zcrx: consolidate dma syncing
io_uring/zcrx: netmem array as refiling format
...
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
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>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
For some cases, the order in which the waitq entry list and head
writing happens is important, for others it doesn't really matter.
But it's somewhat confusing to have them spread out over the file.
Abstract out the nicely documented code in io_pollfree_wake() and
move it into a helper, and use that helper consistently rather than
having other call sites manually do the same thing. While at it,
correct a comment function name as well.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
In preparation for uring_cmd implementations to implement functions
with the io_req_tw_func_t signature, introduce a wrapper struct
io_tw_req to hide the struct io_kiocb * argument. The intention is for
only the io_uring core to access the inner struct io_kiocb *. uring_cmd
implementations should instead call a helper from io_uring/cmd.h to
convert struct io_tw_req to struct io_uring_cmd *.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Rather than do per-tw checking, which needs to dip into the task_struct
for checking flags, do it upfront before running task_work. This places
a 'cancel' member in io_tw_token_t, which is assigned before running
task_work for that given ctx.
This is both more efficient in doing it upfront rather than for every
task_work, and it means that io_should_terminate_tw() can be made
private in io_uring.c rather than need to be called by various
callbacks of task_work.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull io_uring updates from Jens Axboe:
- Store ring provided buffers locally for the users, rather than stuff
them into struct io_kiocb.
These types of buffers must always be fully consumed or recycled in
the current context, and leaving them in struct io_kiocb is hence not
a good ideas as that struct has a vastly different life time.
Basically just an architecture cleanup that can help prevent issues
with ring provided buffers in the future.
- Support for mixed CQE sizes in the same ring.
Before this change, a CQ ring either used the default 16b CQEs, or it
was setup with 32b CQE using IORING_SETUP_CQE32. For use cases where
a few 32b CQEs were needed, this caused everything else to use big
CQEs. This is wasteful both in terms of memory usage, but also memory
bandwidth for the posted CQEs.
With IORING_SETUP_CQE_MIXED, applications may use request types that
post both normal 16b and big 32b CQEs on the same ring.
- Add helpers for async data management, to make it harder for opcode
handlers to mess it up.
- Add support for multishot for uring_cmd, which ublk can use. This
helps improve efficiency, by providing a persistent request type that
can trigger multiple CQEs.
- Add initial support for ring feature querying.
We had basic support for probe operations, but the API isn't great.
Rather than expand that, add support for QUERY which is easily
expandable and can cover a lot more cases than the existing probe
support. This will help applications get a better idea of what
operations are supported on a given host.
- zcrx improvements from Pavel:
- Improve refill entry alignment for better caching
- Various cleanups, especially around deduplicating normal
memory vs dmabuf setup.
- Generalisation of the niov size (Patch 12). It's still hard
coded to PAGE_SIZE on init, but will let the user to specify
the rx buffer length on setup.
- Syscall / synchronous bufer return. It'll be used as a slow
fallback path for returning buffers when the refill queue is
full. Useful for tolerating slight queue size misconfiguration
or with inconsistent load.
- Accounting more memory to cgroups.
- Additional independent cleanups that will also be useful for
mutli-area support.
- Various fixes and cleanups
* tag 'for-6.18/io_uring-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (68 commits)
io_uring/cmd: drop unused res2 param from io_uring_cmd_done()
io_uring: fix nvme's 32b cqes on mixed cq
io_uring/query: cap number of queries
io_uring/query: prevent infinite loops
io_uring/zcrx: account niov arrays to cgroup
io_uring/zcrx: allow synchronous buffer return
io_uring/zcrx: introduce io_parse_rqe()
io_uring/zcrx: don't adjust free cache space
io_uring/zcrx: use guards for the refill lock
io_uring/zcrx: reduce netmem scope in refill
io_uring/zcrx: protect netdev with pp_lock
io_uring/zcrx: rename dma lock
io_uring/zcrx: make niov size variable
io_uring/zcrx: set sgt for umem area
io_uring/zcrx: remove dmabuf_offset
io_uring/zcrx: deduplicate area mapping
io_uring/zcrx: pass ifq to io_zcrx_alloc_fallback()
io_uring/zcrx: check all niovs filled with dma addresses
io_uring/zcrx: move area reg checks into io_import_area
io_uring/zcrx: don't pass slot to io_zcrx_create_area
...
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>
Currently the buffer list is stored in struct io_kiocb. The buffer list
can be of two types:
1) Classic/legacy buffer list. These don't need to get referenced after
a buffer pick, and hence storing them in struct io_kiocb is perfectly
fine.
2) Ring provided buffer lists. These DO need to be referenced after the
initial buffer pick, as they need to get consumed later on. This can
be either just incrementing the head of the ring, or it can be
consuming parts of a buffer if incremental buffer consumptions has
been configured.
For case 2, io_uring needs to be careful not to access the buffer list
after the initial pick-and-execute context. The core does recycling of
these, but it's easy to make a mistake, because it's stored in the
io_kiocb which does persist across multiple execution contexts. Either
because it's a multishot request, or simply because it needed some kind
of async trigger (eg poll) for retry purposes.
Add a struct io_buffer_list to struct io_br_sel, which is always on
stack for the various users of it. This prevents the buffer list from
leaking outside of that execution context, and additionally it enables
kbuf to not even pass back the struct io_buffer_list if the given
context isn't appropriately locked already.
This doesn't fix any bugs, it's simply a defensive measure to prevent
any issues with reuse of a buffer list.
Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull io_uring updates from Jens Axboe:
- Optimization to avoid reference counts on non-cloned registered
buffers. This is how these buffers were handled prior to having
cloning support, and we can still use that approach as long as the
buffers haven't been cloned to another ring.
- Cleanup and improvement for uring_cmd, where btrfs was the only user
of storing allocated data for the lifetime of the uring_cmd. Clean
that up so we can get rid of the need to do that.
- Avoid unnecessary memory copies in uring_cmd usage. This is
particularly important as a lot of uring_cmd usage necessitates the
use of 128b SQEs.
- A few updates for recv multishot, where it's now possible to add
fairness limits for limiting how much is transferred for each retry
loop. Additionally, recv multishot now supports an overall cap as
well, where once reached the multishot recv will terminate. The
latter is useful for buffer management and juggling many recv streams
at the same time.
- Add support for returning the TX timestamps via a new socket command.
This feature can work in either singleshot or multishot mode, where
the latter triggers a completion whenever new timestamps are
available. This is an alternative to using the existing error queue.
- Add support for an io_uring "mock" file, which is the start of being
able to do 100% targeted testing in terms of exercising io_uring
request handling. The idea is to have a file type that can be
anything the tester would like, and behave exactly how you want it to
behave in terms of hitting the code paths you want.
- Improve zcrx by using sgtables to de-duplicate and improve dma
address handling.
- Prep work for supporting larger pages for zcrx.
- Various little improvements and fixes.
* tag 'for-6.17/io_uring-20250728' of git://git.kernel.dk/linux: (42 commits)
io_uring/zcrx: fix leaking pages on sg init fail
io_uring/zcrx: don't leak pages on account failure
io_uring/zcrx: fix null ifq on area destruction
io_uring: fix breakage in EXPERT menu
io_uring/cmd: remove struct io_uring_cmd_data
btrfs/ioctl: store btrfs_uring_encoded_data in io_btrfs_cmd
io_uring/cmd: introduce IORING_URING_CMD_REISSUE flag
io_uring/zcrx: account area memory
io_uring: export io_[un]account_mem
io_uring/net: Support multishot receive len cap
io_uring: deduplicate wakeup handling
io_uring/net: cast min_not_zero() type
io_uring/poll: cleanup apoll freeing
io_uring/net: allow multishot receive per-invocation cap
io_uring/net: move io_sr_msg->retry_flags to io_sr_msg->flags
io_uring/net: use passed in 'len' in io_recv_buf_select()
io_uring/zcrx: prepare fallback for larger pages
io_uring/zcrx: assert area type in io_zcrx_iov_page
io_uring/zcrx: allocate sgtable for umem areas
io_uring/zcrx: introduce io_populate_area_dma
...
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>
IOU_COMPLETE is more descriptive, in that it explicitly says that the
return value means "please post a completion for this request". This
patch completes the transition from IOU_OK to IOU_COMPLETE, replacing
existing IOU_OK users.
This is a purely mechanical change.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Multishot errors can be mapped 1:1 to normal errors, but there are not
identical. It leads to a peculiar situation where all multishot requests
has to check in what context they're run and return different codes.
Unify them starting with EAGAIN / IOU_ISSUE_SKIP_COMPLETE(EIOCBQUEUED)
pair, which mean that core io_uring still owns the request and it should
be retried. In case of multishot it's naturally just continues to poll,
otherwise it might poll, use iowq or do any other kind of allowed
blocking. Introduce IOU_RETRY aliased to -EAGAIN for that.
Apart from obvious upsides, multishot can now also check for misuse of
IOU_ISSUE_SKIP_COMPLETE.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/da117b79ce72ecc3ab488c744e29fae9ba54e23b.1741453534.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for changing how io_tw_state is passed, introduce a type
alias io_tw_token_t for struct io_tw_state *. This allows for changing
the representation in one place, without having to update the many
functions that just forward their struct io_tw_state * argument.
Also add a comment to struct io_tw_state to explain its purpose.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250217022511.1150145-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
Jens Axboe
Longxuan YuandJens Axboe
Linus Torvalds
Kees Cook
Caleb Sander MateosandJens Axboe
Pavel BegunkovandJens Axboe