We need to decouple the clearing on wakeup from the the inline schedule,
as that is going to be required for handling multiple rings in one
thread.
Wrap our wakeup handler so we can clear it when we get the wakeup, by
definition that is when we no longer need the flag set.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is in preparation to sharing the poller thread between rings. For
that we need per-ring wait_queue_entry storage, and we can't easily put
that on the stack if one thread is managing multiple rings.
We'll also be sharing the wait_queue_head across rings for the purposes
of wakeups, provide the usual private ring wait_queue_head for now but
make it a pointer so we can easily override it when sharing.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We're not handling signals by default in kernel threads, and we never
use TWA_SIGNAL for the SQPOLL thread internally. Hence we can never
have a signal pending, and we don't need to check for it (nor flush it).
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch adds a new IORING_SETUP_R_DISABLED flag to start the
rings disabled, allowing the user to register restrictions,
buffers, files, before to start processing SQEs.
When IORING_SETUP_R_DISABLED is set, SQE are not processed and
SQPOLL kthread is not started.
The restrictions registration are allowed only when the rings
are disable to prevent concurrency issue while processing SQEs.
The rings can be enabled using IORING_REGISTER_ENABLE_RINGS
opcode with io_uring_register(2).
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The new io_uring_register(2) IOURING_REGISTER_RESTRICTIONS opcode
permanently installs a feature allowlist on an io_ring_ctx.
The io_ring_ctx can then be passed to untrusted code with the
knowledge that only operations present in the allowlist can be
executed.
The allowlist approach ensures that new features added to io_uring
do not accidentally become available when an existing application
is launched on a newer kernel version.
Currently is it possible to restrict sqe opcodes, sqe flags, and
register opcodes.
IOURING_REGISTER_RESTRICTIONS can only be made once. Afterwards
it is not possible to change restrictions anymore.
This prevents untrusted code from removing restrictions.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we don't get and assign the namespace for the async work, then certain
paths just don't work properly (like /dev/stdin, /proc/mounts, etc).
Anything that references the current namespace of the given task should
be assigned for async work on behalf of that task.
Cc: stable@vger.kernel.org # v5.5+
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Grab actual references to the files_struct. To avoid circular references
issues due to this, we add a per-task note that keeps track of what
io_uring contexts a task has used. When the tasks execs or exits its
assigned files, we cancel requests based on this tracking.
With that, we can grab proper references to the files table, and no
longer need to rely on stashing away ring_fd and ring_file to check
if the ring_fd may have been closed.
Cc: stable@vger.kernel.org # v5.5+
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This allows us to selectively flush out pending overflows, depending on
the task and/or files_struct being passed in.
No intended functional changes in this patch.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Return whether we found and canceled requests or not. This is in
preparation for using this information, no functional changes in this
patch.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Sometimes we assign a weak reference to it, sometimes we grab a
reference to it. Clean this up and make it unconditional, and drop the
flag related to tracking this state.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We can grab a reference to the task instead of stashing away the task
files_struct. This is doable without creating a circular reference
between the ring fd and the task itself.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
No functional changes in this patch, prep patch for grabbing references
to the files_struct.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We currently cancel these when the ring exits, and we cancel all of
them. This is in preparation for killing only the ones associated
with a given task.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The async buffered reads feature is not working when readahead is
turned off. There are two things to concern:
- when doing retry in io_read, not only the IOCB_WAITQ flag but also
the IOCB_NOWAIT flag is still set, which makes it goes to would_block
phase in generic_file_buffered_read() and then return -EAGAIN. After
that, the io-wq thread work is queued, and later doing the async
reads in the old way.
- even if we remove IOCB_NOWAIT when doing retry, the feature is still
not running properly, since in generic_file_buffered_read() it goes to
lock_page_killable() after calling mapping->a_ops->readpage() to do
IO, and thus causing process to sleep.
Fixes: 1a0a7853b9 ("mm: support async buffered reads in generic_file_buffered_read()")
Fixes: 3b2a4439e0 ("io_uring: get rid of kiocb_wait_page_queue_init()")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'io_uring-5.9-2020-09-25' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
"Two fixes for regressions in this cycle, and one that goes to 5.8
stable:
- fix leak of getname() retrieved filename
- remove plug->nowait assignment, fixing a regression with btrfs
- fix for async buffered retry"
* tag 'io_uring-5.9-2020-09-25' of git://git.kernel.dk/linux-block:
io_uring: ensure async buffered read-retry is setup properly
io_uring: don't unconditionally set plug->nowait = true
io_uring: ensure open/openat2 name is cleaned on cancelation
A previous commit for fixing up short reads botched the async retry
path, so we ended up going to worker threads more often than we should.
Fix this up, so retries work the way they originally were intended to.
Fixes: 227c0c9673 ("io_uring: internally retry short reads")
Reported-by: Hao_Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This causes all the bios to be submitted with REQ_NOWAIT, which can be
problematic on either btrfs or on file systems that otherwise use a mix
of block devices where only some of them support it.
For now, just remove the setting of plug->nowait = true.
Reported-by: Dan Melnic <dmm@fb.com>
Reported-by: Brian Foster <bfoster@redhat.com>
Fixes: b63534c41e ("io_uring: re-issue block requests that failed because of resources")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we cancel these requests, we'll leak the memory associated with the
filename. Add them to the table of ops that need cleaning, if
REQ_F_NEED_CLEANUP is set.
Cc: stable@vger.kernel.org
Fixes: e62753e4e2 ("io_uring: call statx directly")
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Two minor conflicts:
1) net/ipv4/route.c, adding a new local variable while
moving another local variable and removing it's
initial assignment.
2) drivers/net/dsa/microchip/ksz9477.c, overlapping changes.
One pretty prints the port mode differently, whilst another
changes the driver to try and obtain the port mode from
the port node rather than the switch node.
Signed-off-by: David S. Miller <davem@davemloft.net>
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Merge tag 'io_uring-5.9-2020-09-22' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
"A few fixes - most of them regression fixes from this cycle, but also
a few stable heading fixes, and a build fix for the included demo tool
since some systems now actually have gettid() available"
* tag 'io_uring-5.9-2020-09-22' of git://git.kernel.dk/linux-block:
io_uring: fix openat/openat2 unified prep handling
io_uring: mark statx/files_update/epoll_ctl as non-SQPOLL
tools/io_uring: fix compile breakage
io_uring: don't use retry based buffered reads for non-async bdev
io_uring: don't re-setup vecs/iter in io_resumit_prep() is already there
io_uring: don't run task work on an exiting task
io_uring: drop 'ctx' ref on task work cancelation
io_uring: grab any needed state during defer prep
A previous commit unified how we handle prep for these two functions,
but this means that we check the allowed context (SQPOLL, specifically)
later than we should. Move the ring type checking into the two parent
functions, instead of doing it after we've done some setup work.
Fixes: ec65fea5a8 ("io_uring: deduplicate io_openat{,2}_prep()")
Reported-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These will naturally fail when attempted through SQPOLL, but either
with -EFAULT or -EBADF. Make it explicit that these are not workable
through SQPOLL and return -EINVAL, just like other ops that need to
use ->files.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Some block devices, like dm, bubble back -EAGAIN through the completion
handler. We check for this in io_read(), but don't honor it for when
we have copied the iov. Return -EAGAIN for this case before retrying,
to force punt to io-wq.
Fixes: bcf5a06304 ("io_uring: support true async buffered reads, if file provides it")
Reported-by: Zorro Lang <zlang@redhat.com>
Tested-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we already have mapped the necessary data for retry, then don't set
it up again. It's a pointless operation, and we leak the iovec if it's
a large (non-stack) vec.
Fixes: b63534c41e ("io_uring: re-issue block requests that failed because of resources")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This isn't safe, and isn't needed either. We are guaranteed that any
work we queue is on a live task (and will be run), or it goes to
our backup io-wq threads if the task is exiting.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If task_work ends up being marked for cancelation, we go through a
cancelation helper instead of the queue path. In converting task_work to
always hold a ctx reference, this path was missed. Make sure that
io_req_task_cancel() puts the reference that is being held against the
ctx.
Fixes: 6d816e088c ("io_uring: hold 'ctx' reference around task_work queue + execute")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Always grab work environment for deferred links. The assumption that we
will be running it always from the task in question is false, as exiting
tasks may mean that we're deferring this one to a thread helper. And at
that point it's too late to grab the work environment.
Fixes: debb85f496 ("io_uring: factor out grab_env() from defer_prep()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'io_uring-5.9-2020-09-06' of git://git.kernel.dk/linux-block
Pull more io_uring fixes from Jens Axboe:
"Two followup fixes. One is fixing a regression from this merge window,
the other is two commits fixing cancelation of deferred requests.
Both have gone through full testing, and both spawned a few new
regression test additions to liburing.
- Don't play games with const, properly store the output iovec and
assign it as needed.
- Deferred request cancelation fix (Pavel)"
* tag 'io_uring-5.9-2020-09-06' of git://git.kernel.dk/linux-block:
io_uring: fix linked deferred ->files cancellation
io_uring: fix cancel of deferred reqs with ->files
io_uring: fix explicit async read/write mapping for large segments
While looking for ->files in ->defer_list, consider that requests there
may actually be links.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While trying to cancel requests with ->files, it also should look for
requests in ->defer_list, otherwise it might end up hanging a thread.
Cancel all requests in ->defer_list up to the last request there with
matching ->files, that's needed to follow drain ordering semantics.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we exceed UIO_FASTIOV, we don't handle the transition correctly
between an allocated vec for requests that are queued with IOSQE_ASYNC.
Store the iovec appropriately and re-set it in the iter iov in case
it changed.
Fixes: ff6165b2d7 ("io_uring: retain iov_iter state over io_read/io_write calls")
Reported-by: Nick Hill <nick@nickhill.org>
Tested-by: Norman Maurer <norman.maurer@googlemail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We got slightly different patches removing a double word
in a comment in net/ipv4/raw.c - picked the version from net.
Simple conflict in drivers/net/ethernet/ibm/ibmvnic.c. Use cached
values instead of VNIC login response buffer (following what
commit 507ebe6444 ("ibmvnic: Fix use-after-free of VNIC login
response buffer") did).
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'io_uring-5.9-2020-09-04' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
- EAGAIN with O_NONBLOCK retry fix
- Two small fixes for registered files (Jiufei)
* tag 'io_uring-5.9-2020-09-04' of git://git.kernel.dk/linux-block:
io_uring: no read/write-retry on -EAGAIN error and O_NONBLOCK marked file
io_uring: set table->files[i] to NULL when io_sqe_file_register failed
io_uring: fix removing the wrong file in __io_sqe_files_update()
Actually two things that need fixing up here:
- The io_rw_reissue() -EAGAIN retry is explicit to block devices and
regular files, so don't ever attempt to do that on other types of
files.
- If we hit -EAGAIN on a nonblock marked file, don't arm poll handler for
it. It should just complete with -EAGAIN.
Cc: stable@vger.kernel.org
Reported-by: Norman Maurer <norman.maurer@googlemail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While io_sqe_file_register() failed in __io_sqe_files_update(),
table->files[i] still point to the original file which may freed
soon, and that will trigger use-after-free problems.
Cc: stable@vger.kernel.org
Fixes: f3bd9dae37 ("io_uring: fix memleak in __io_sqe_files_update()")
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Index here is already the position of the file in fixed_file_table, we
should not use io_file_from_index() again to get it. Otherwise, the
wrong file which still in use may be released unexpectedly.
Cc: stable@vger.kernel.org # v5.6
Fixes: 05f3fb3c53 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'io_uring-5.9-2020-08-28' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
"A few fixes in here, all based on reports and test cases from folks
using it. Most of it is stable material as well:
- Hashed work cancelation fix (Pavel)
- poll wakeup signalfd fix
- memlock accounting fix
- nonblocking poll retry fix
- ensure we never return -ERESTARTSYS for reads
- ensure offset == -1 is consistent with preadv2() as documented
- IOPOLL -EAGAIN handling fixes
- remove useless task_work bounce for block based -EAGAIN retry"
* tag 'io_uring-5.9-2020-08-28' of git://git.kernel.dk/linux-block:
io_uring: don't bounce block based -EAGAIN retry off task_work
io_uring: fix IOPOLL -EAGAIN retries
io_uring: clear req->result on IOPOLL re-issue
io_uring: make offset == -1 consistent with preadv2/pwritev2
io_uring: ensure read requests go through -ERESTART* transformation
io_uring: don't use poll handler if file can't be nonblocking read/written
io_uring: fix imbalanced sqo_mm accounting
io_uring: revert consumed iov_iter bytes on error
io-wq: fix hang after cancelling pending hashed work
io_uring: don't recurse on tsk->sighand->siglock with signalfd
These events happen inline from submission, so there's no need to
bounce them through the original task. Just set them up for retry
and issue retry directly instead of going over task_work.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This normally isn't hit, as polling is mostly done on NVMe with deep
queue depths. But if we do run into request starvation, we need to
ensure that retries are properly serialized.
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make sure we clear req->result, which was set to -EAGAIN for retry
purposes, when moving it to the reissue list. Otherwise we can end up
retrying a request more than once, which leads to weird results in
the io-wq handling (and other spots).
Cc: stable@vger.kernel.org
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The man page for io_uring generally claims were consistent with what
preadv2 and pwritev2 accept, but turns out there's a slight discrepancy
in how offset == -1 is handled for pipes/streams. preadv doesn't allow
it, but preadv2 does. This currently causes io_uring to return -EINVAL
if that is attempted, but we should allow that as documented.
This change makes us consistent with preadv2/pwritev2 for just passing
in a NULL ppos for streams if the offset is -1.
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Benedikt Ames <wisp3rwind@posteo.eu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We need to call kiocb_done() for any ret < 0 to ensure that we always
get the proper -ERESTARTSYS (and friends) transformation done.
At some point this should be tied into general error handling, so we
can get rid of the various (mostly network) related commands that check
and perform this substitution.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There's no point in using the poll handler if we can't do a nonblocking
IO attempt of the operation, since we'll need to go async anyway. In
fact this is actively harmful, as reading from eg pipes won't return 0
to indicate EOF.
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Benedikt Ames <wisp3rwind@posteo.eu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We do the initial accounting of locked_vm and pinned_vm before we have
setup ctx->sqo_mm, which means we can end up having not accounted the
memory at setup time, but still decrement it when we exit. This causes
an imbalance in the accounting.
Setup ctx->sqo_mm earlier in io_uring_create(), before we do the first
accounting of mm->{locked,pinned}_vm. This also unifies the state
grabbing for the ctx, and eliminates a failure case in
io_sq_offload_start().
Fixes: f74441e631 ("io_uring: account locked memory before potential error case")
Reported-by: Robert M. Muncrief <rmuncrief@humanavance.com>
Reported-by: Niklas Schnelle <schnelle@linux.ibm.com>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Tested-by: Robert M. Muncrief <rmuncrief@humanavance.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Some consumers of the iov_iter will return an error, but still have
bytes consumed in the iterator. This is an issue for -EAGAIN, since we
rely on a sane iov_iter state across retries.
Fix this by ensuring that we revert consumed bytes, if any, if the file
operations have consumed any bytes from iterator. This is similar to what
generic_file_read_iter() does, and is always safe as we have the previous
bytes count handy already.
Fixes: ff6165b2d7 ("io_uring: retain iov_iter state over io_read/io_write calls")
Reported-by: Dmitry Shulyak <yashulyak@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, io_uring's recvmsg subscribes to both POLLERR and POLLIN. In
the context of TCP tx zero-copy, this is inefficient since we are only
reading the error queue and not using recvmsg to read POLLIN responses.
This patch was tested by using a simple sending program to call recvmsg
using io_uring with MSG_ERRQUEUE set and verifying with printks that the
POLLIN is correctly unset when the msg flags are MSG_ERRQUEUE.
Signed-off-by: Arjun Roy <arjunroy@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Luke Hsiao <lukehsiao@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If an application is doing reads on signalfd, and we arm the poll handler
because there's no data available, then the wakeup can recurse on the
tasks sighand->siglock as the signal delivery from task_work_add() will
use TWA_SIGNAL and that attempts to lock it again.
We can detect the signalfd case pretty easily by comparing the poll->head
wait_queue_head_t with the target task signalfd wait queue. Just use
normal task wakeup for this case.
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If io_import_iovec() returns an error, return iovec is undefined and
must not be used, so don't set it to NULL when failing.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
kfree() handles NULL pointers well, but io_{read,write}() checks it
because of performance reasons. Leave a comment there for those who are
tempted to patch it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Setting and clearing REQ_F_OVERFLOW in io_uring_cancel_files() and
io_cqring_overflow_flush() are racy, because they might be called
asynchronously.
REQ_F_OVERFLOW flag in only needed for files cancellation, so if it can
be guaranteed that requests _currently_ marked inflight can't be
overflown, the problem will be solved with removing the flag
altogether.
That's how the patch works, it removes inflight status of a request
in io_cqring_fill_event() whenever it should be thrown into CQ-overflow
list. That's Ok to do, because no opcode specific handling can be done
after io_cqring_fill_event(), the same assumption as with "struct
io_completion" patches.
And it already have a good place for such cleanups, which is
io_clean_op(). A nice side effect of this is removing this inflight
check from the hot path.
note on synchronisation: now __io_cqring_fill_event() may be taking two
spinlocks simultaneously, completion_lock and inflight_lock. It's fine,
because we never do that in reverse order, and CQ-overflow of inflight
requests shouldn't happen often.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We currently use system_wq, which is unbounded in terms of number of
workers. This means that if we're exiting tons of rings at the same
time, then we'll briefly spawn tons of event kworkers just for a very
short blocking time as the rings exit.
Use system_unbound_wq instead, which has a sane cap on the concurrency
level.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_rw_prep_async() goes through a dance of clearing req->io, calling
the iovec import, then re-setting req->io. Provide an internal helper
that does the right thing without needing state tweaked to get there.
This enables further cleanups in io_read, io_write, and
io_resubmit_prep(), but that's left for another time.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The 5.9 merge moved this function io_uring, which means that we don't
need to retain the generic nature of it. Clean up this part by removing
redundant checks, and just inlining the small remainder in
io_rw_should_retry().
No functional changes in this patch.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit f254ac04c8 ("io_uring: enable lookup of links holding inflight files")
only handled 2 out of the three head link cases we have, we also need to
lookup and cancel work that is blocked in io-wq if that work has a link
that's holding a reference to the files structure.
Put the "cancel head links that hold this request pending" logic into
io_attempt_cancel(), which will to through the motions of finding and
canceling head links that hold the current inflight files stable request
pending.
Cc: stable@vger.kernel.org
Reported-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
One case was missed in the short IO retry handling, and that's hitting
-EAGAIN on a blocking attempt read (eg from io-wq context). This is a
problem on sockets that are marked as non-blocking when created, they
don't carry any REQ_F_NOWAIT information to help us terminate them
instead of perpetually retrying.
Fixes: 227c0c9673 ("io_uring: internally retry short reads")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There's a bit of confusion on the matching pairs of poll vs double poll,
depending on if the request is a pure poll (IORING_OP_POLL_ADD) or
poll driven retry.
Add io_poll_get_double() that returns the double poll waitqueue, if any,
and io_poll_get_single() that returns the original poll waitqueue. With
that, remove the argument to io_poll_remove_double().
Finally ensure that wait->private is cleared once the double poll handler
has run, so that remove knows it's already been seen.
Cc: stable@vger.kernel.org # v5.8
Reported-by: syzbot+7f617d4a9369028b8a2c@syzkaller.appspotmail.com
Fixes: 18bceab101 ("io_uring: allow POLL_ADD with double poll_wait() users")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We've had a few application cases of not handling short reads properly,
and it is understandable as short reads aren't really expected if the
application isn't doing non-blocking IO.
Now that we retain the iov_iter over retries, we can implement internal
retry pretty trivially. This ensures that we don't return a short read,
even for buffered reads on page cache conflicts.
Cleanup the deep nesting and hard to read nature of io_read() as well,
it's much more straight forward now to read and understand. Added a
few comments explaining the logic as well.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of maintaining (and setting/remembering) iov_iter size and
segment counts, just put the iov_iter in the async part of the IO
structure.
This is mostly a preparation patch for doing appropriate internal retries
for short reads, but it also cleans up the state handling nicely and
simplifies it quite a bit.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a process exits, we cancel whatever requests it has pending that
are referencing the file table. However, if a link is holding a
reference, then we cannot find it by simply looking at the inflight
list.
Enable checking of the poll and timeout list to find the link, and
cancel it appropriately.
Cc: stable@vger.kernel.org
Reported-by: Josef <josef.grieb@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Check the ipt.error value, it must have been either cleared to zero or
set to another error than the default -EINVAL if we don't go through the
waitqueue proc addition. Just give up on poll at that point and return
failure, this will fallback to async work.
io_poll_add() doesn't suffer from this failure case, as it returns the
error value directly.
Cc: stable@vger.kernel.org # v5.7+
Reported-by: syzbot+a730016dc0bdce4f6ff5@syzkaller.appspotmail.com
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We're holding the request reference, but we need to go one higher
to ensure that the ctx remains valid after the request has finished.
If the ring is closed with pending task_work inflight, and the
given io_kiocb finishes sync during issue, then we need a reference
to the ring itself around the task_work execution cycle.
Cc: stable@vger.kernel.org # v5.7+
Reported-by: syzbot+9b260fc33297966f5a8e@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we're in the error path failing links and we have a link that has
grabbed a reference to the fs_struct, then we cannot safely drop our
reference to the table if we already hold the completion lock. This
adds a hardirq dependency to the fs_struct->lock, which it currently
doesn't have.
Defer the final cleanup and free of such requests to avoid adding this
dependency.
Reported-by: syzbot+ef4b654b49ed7ff049bf@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When we traverse into failing links or timeouts, we need to ensure we
propagate the REQ_F_COMP_LOCKED flag to ensure that we correctly signal
to the completion side that we already hold the completion lock.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
syszbot reports a scenario where we recurse on the completion lock
when flushing an overflow:
1 lock held by syz-executor287/6816:
#0: ffff888093cdb4d8 (&ctx->completion_lock){....}-{2:2}, at: io_cqring_overflow_flush+0xc6/0xab0 fs/io_uring.c:1333
stack backtrace:
CPU: 1 PID: 6816 Comm: syz-executor287 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1f0/0x31e lib/dump_stack.c:118
print_deadlock_bug kernel/locking/lockdep.c:2391 [inline]
check_deadlock kernel/locking/lockdep.c:2432 [inline]
validate_chain+0x69a4/0x88a0 kernel/locking/lockdep.c:3202
__lock_acquire+0x1161/0x2ab0 kernel/locking/lockdep.c:4426
lock_acquire+0x160/0x730 kernel/locking/lockdep.c:5005
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x67/0x80 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:379 [inline]
io_queue_linked_timeout fs/io_uring.c:5928 [inline]
__io_queue_async_work fs/io_uring.c:1192 [inline]
__io_queue_deferred+0x36a/0x790 fs/io_uring.c:1237
io_cqring_overflow_flush+0x774/0xab0 fs/io_uring.c:1359
io_ring_ctx_wait_and_kill+0x2a1/0x570 fs/io_uring.c:7808
io_uring_release+0x59/0x70 fs/io_uring.c:7829
__fput+0x34f/0x7b0 fs/file_table.c:281
task_work_run+0x137/0x1c0 kernel/task_work.c:135
exit_task_work include/linux/task_work.h:25 [inline]
do_exit+0x5f3/0x1f20 kernel/exit.c:806
do_group_exit+0x161/0x2d0 kernel/exit.c:903
__do_sys_exit_group+0x13/0x20 kernel/exit.c:914
__se_sys_exit_group+0x10/0x10 kernel/exit.c:912
__x64_sys_exit_group+0x37/0x40 kernel/exit.c:912
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fix this by passing back the link from __io_queue_async_work(), and
then let the caller handle the queueing of the link. Take care to also
punt the submission reference put to the caller, as we're holding the
completion lock for the __io_queue_defer() case. Hence we need to mark
the io_kiocb appropriately for that case.
Reported-by: syzbot+996f91b6ec3812c48042@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
An earlier commit:
b7db41c9e0 ("io_uring: fix regression with always ignoring signals in io_cqring_wait()")
ensured that we didn't get stuck waiting for eventfd reads when it's
registered with the io_uring ring for event notification, but we still
have cases where the task can be waiting on other events in the kernel and
need a bigger nudge to make forward progress. Or the task could be in the
kernel and running, but on its way to blocking.
This means that TWA_RESUME cannot reliably be used to ensure we make
progress. Use TWA_SIGNAL unconditionally.
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Josef <josef.grieb@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The tear down path will always unaccount the memory, so ensure that we
have accounted it before hitting any of them.
Reported-by: Tomáš Chaloupka <chalucha@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we hit an earlier error path in io_uring_create(), then we will have
accounted memory, but not set ctx->{sq,cq}_entries yet. Then when the
ring is torn down in error, we use those values to unaccount the memory.
Ensure we set the ctx entries before we're able to hit a potential error
path.
Cc: stable@vger.kernel.org
Reported-by: Tomáš Chaloupka <chalucha@gmail.com>
Tested-by: Tomáš Chaloupka <chalucha@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The retry based logic here isn't easy to follow unless you're already
familiar with how io_uring does task_work based retries. Add some
comments explaining the flow a little better.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since we don't do exclusive waits or wakeups, we know that the bit is
always going to be set. Kill the test. Also see commit:
2a9127fcf2 ("mm: rewrite wait_on_page_bit_common() logic")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block
Pull io_uring updates from Jens Axboe:
"Lots of cleanups in here, hardening the code and/or making it easier
to read and fixing bugs, but a core feature/change too adding support
for real async buffered reads. With the latter in place, we just need
buffered write async support and we're done relying on kthreads for
the fast path. In detail:
- Cleanup how memory accounting is done on ring setup/free (Bijan)
- sq array offset calculation fixup (Dmitry)
- Consistently handle blocking off O_DIRECT submission path (me)
- Support proper async buffered reads, instead of relying on kthread
offload for that. This uses the page waitqueue to drive retries
from task_work, like we handle poll based retry. (me)
- IO completion optimizations (me)
- Fix race with accounting and ring fd install (me)
- Support EPOLLEXCLUSIVE (Jiufei)
- Get rid of the io_kiocb unionizing, made possible by shrinking
other bits (Pavel)
- Completion side cleanups (Pavel)
- Cleanup REQ_F_ flags handling, and kill off many of them (Pavel)
- Request environment grabbing cleanups (Pavel)
- File and socket read/write cleanups (Pavel)
- Improve kiocb_set_rw_flags() (Pavel)
- Tons of fixes and cleanups (Pavel)
- IORING_SQ_NEED_WAKEUP clear fix (Xiaoguang)"
* tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block: (127 commits)
io_uring: flip if handling after io_setup_async_rw
fs: optimise kiocb_set_rw_flags()
io_uring: don't touch 'ctx' after installing file descriptor
io_uring: get rid of atomic FAA for cq_timeouts
io_uring: consolidate *_check_overflow accounting
io_uring: fix stalled deferred requests
io_uring: fix racy overflow count reporting
io_uring: deduplicate __io_complete_rw()
io_uring: de-unionise io_kiocb
io-wq: update hash bits
io_uring: fix missing io_queue_linked_timeout()
io_uring: mark ->work uninitialised after cleanup
io_uring: deduplicate io_grab_files() calls
io_uring: don't do opcode prep twice
io_uring: clear IORING_SQ_NEED_WAKEUP after executing task works
io_uring: batch put_task_struct()
tasks: add put_task_struct_many()
io_uring: return locked and pinned page accounting
io_uring: don't miscount pinned memory
io_uring: don't open-code recv kbuf managment
...
As recently done with with send/recv, flip the if after
rw_verify_aread() in io_{read,write}() and tabulise left bits left.
This removes mispredicted by a compiler jump on the success/fast path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As soon as we install the file descriptor, we have to assume that it
can get arbitrarily closed. We currently account memory (and note that
we did) after installing the ring fd, which means that it could be a
potential use-after-free condition if the fd is closed right after
being installed, but before we fiddle with the ctx.
In fact, syzbot reported this exact scenario:
BUG: KASAN: use-after-free in io_account_mem fs/io_uring.c:7397 [inline]
BUG: KASAN: use-after-free in io_uring_create fs/io_uring.c:8369 [inline]
BUG: KASAN: use-after-free in io_uring_setup+0x2797/0x2910 fs/io_uring.c:8400
Read of size 1 at addr ffff888087a41044 by task syz-executor.5/18145
CPU: 0 PID: 18145 Comm: syz-executor.5 Not tainted 5.8.0-rc7-next-20200729-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
io_account_mem fs/io_uring.c:7397 [inline]
io_uring_create fs/io_uring.c:8369 [inline]
io_uring_setup+0x2797/0x2910 fs/io_uring.c:8400
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c429
Code: 8d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8f121d0c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 0000000000008540 RCX: 000000000045c429
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000196
RBP: 000000000078bf38 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007fff86698cff R14: 00007f8f121d19c0 R15: 000000000078bf0c
Move the accounting of the ring used locked memory before we get and
install the ring file descriptor.
Cc: stable@vger.kernel.org
Reported-by: syzbot+9d46305e76057f30c74e@syzkaller.appspotmail.com
Fixes: 309758254e ("io_uring: report pinned memory usage")
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If ->cq_timeouts modifications are done under ->completion_lock, we
don't really nee any fetch-and-add and other complex atomics. Replace it
with non-atomic FAA, that saves an implicit full memory barrier.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper to mark ctx->{cq,sq}_check_overflow to get rid of
duplicates, and it's clearer to check cq_overflow_list directly anyway.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Always do io_commit_cqring() after completing a request, even if it was
accounted as overflowed on the CQ side. Failing to do that may lead to
not to pushing deferred requests when needed, and so stalling the whole
ring.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All ->cq_overflow modifications should be under completion_lock,
otherwise it can report a wrong number to the userspace. Fix it in
io_uring_cancel_files().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Call __io_complete_rw() in io_iopoll_queue() instead of hand coding it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As io_kiocb have enough space, move ->work out of a union. It's safer
this way and removes ->work memcpy bouncing.
By the way make tabulation in struct io_kiocb consistent.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Whoever called io_prep_linked_timeout() should also do
io_queue_linked_timeout(). __io_queue_sqe() doesn't follow that for the
punting path leaving linked timeouts prepared but never queued.
Fixes: 6df1db6b54 ("io_uring: fix mis-refcounting linked timeouts")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove REQ_F_WORK_INITIALIZED after io_req_clean_work(). That's a cold
path but is safer for those using io_req_clean_work() out of
*dismantle_req()/*io_free(). And for the same reason zero work.fs
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move io_req_init_async() into io_grab_files(), it's safer this way. Note
that io_queue_async_work() does *init_async(), so it's valid to move out
of __io_queue_sqe() punt path. Also, add a helper around io_grab_files().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Calling into opcode prep handlers may be dangerous, as they re-read
SQE but might not re-initialise requests completely. If io_req_defer()
passed fast checks and is done with preparations, punt it async.
As all other cases are covered with nulling @sqe, this guarantees that
io_[opcode]_prep() are visited only once per request.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In io_sq_thread(), if there are task works to handle, current codes
will skip schedule() and go on polling sq again, but forget to clear
IORING_SQ_NEED_WAKEUP flag, fix this issue. Also add two helpers to
set and clear IORING_SQ_NEED_WAKEUP flag,
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As every iopoll request have a task ref, it becomes expensive to put
them one by one, instead we can put several at once integrating that
into io_req_free_batch().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Locked and pinned memory accounting in io_{,un}account_mem() depends on
having ->sqo_mm, which is NULL after a recent change for non SQPOLL'ed
io_ring. That disables the accounting.
Return ->sqo_mm initialisation back, and do __io_sq_thread_acquire_mm()
based on IORING_SETUP_SQPOLL flag.
Fixes: 8eb06d7e8d ("io_uring: fix missing ->mm on exit")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_sqe_buffer_unregister() uses cxt->sqo_mm for memory accounting, but
io_ring_ctx_free() drops ->sqo_mm before leaving pinned_vm
over-accounted. Postpone mm cleanup for when it's not needed anymore.
Fixes: 309758254e ("io_uring: report pinned memory usage")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't implement fast path of kbuf freeing and management inlined into
io_recv{,msg}(), that's error prone and duplicates handling. Replace it
with a helper io_put_recv_kbuf(), which mimics io_put_rw_kbuf() in the
io_read/write().
This also keeps cflags calculation in one place, removing duplication
between rw and recv/send.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Extract a common helper for cleaning up a selected buffer, this will be
used shortly. By the way, correct cflags types to unsigned and, as kbufs
are anyway tracked by a flag, remove useless zeroing req->rw.addr.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move REQ_F_BUFFER_SELECT flag check out of io_recv_buffer_select(), and
do that in its call sites That saves us from double error checking and
possibly an extra function call.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_clean_op() may be skipped even if there is a selected io_buffer,
that's because *select_buffer() funcions never set REQ_F_NEED_CLEANUP.
Trigger io_clean_op() when REQ_F_BUFFER_SELECTED is set as well, and
and clear the flag if was freed out of it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of returning error from io_recv(), go through generic cleanup
path, because it'll retain cflags for userspace. Do the same for
io_send() for consistency.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the return on a bad socket, kmsg is always non-null by the end
of the function, prune left extra checks and initialisations.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Flip over "if (sock)" condition with return on error, the upper layer
will take care. That change will be handy later, but already removes
an extra jump from hot path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, file refs in struct io_submit_state are tracked with 2 vars:
@has_refs -- how many refs were initially taken
@used_refs -- number of refs used
Replace it with a single variable counting how many refs left at the
current moment.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
RLIMIT_SIZE in needed only for execution from an io-wq context, hence
move all preparations from hot path to io-wq work setup.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Every call to io_req_defer_prep() is prepended with allocating ->io,
just do that in the function. And while we're at it, mark error paths
with unlikey and replace "if (ret < 0)" with "if (ret)".
There is only one change in the observable behaviour, that's instead of
killing the head request right away on error, it postpones it until the
link is assembled, that looks more preferable.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A switch in __io_clean_op() doesn't have default, it's pointless to list
opcodes that doesn't do any cleanup. Remove IORING_OP_OPEN* from there.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The only caller of io_req_work_grab_env() is io_prep_async_work(), and
they are both initialising req->work. Inline grab_env(), it's easier
to keep this way, moreover there already were bugs with misplacing
io_req_init_async().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
req->cflags is used only for defer-completion path, just use completion
data to store it. With the 4 bytes from the ->sequence patch and
compacting io_kiocb, this frees 8 bytes.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
req->sequence is used only for deferred (i.e. DRAIN) requests, but
initialised for every request. Remove req->sequence from io_kiocb
together with its initialisation in io_init_req().
Replace it with a new field in struct io_defer_entry, that will be
calculated only when needed in io_req_defer(), which is a slow path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The only left user of req->list is DRAIN, hence instead of keeping a
separate per request list for it, do that with old fashion non-intrusive
lists allocated on demand. That's a really slow path, so that's OK.
This removes req->list and so sheds 16 bytes from io_kiocb.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of using shared req->list, hang timeouts up on their own list
entry. struct io_timeout have enough extra space for it, but if that
will be a problem ->inflight_entry can reused for that.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As with the completion path, also use compl.list for overflowed
requests. If cleaned up properly, nobody needs per-op data there
anymore.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
req->inflight_entry is used to track requests that grabbed files_struct.
Let's share it with iopoll list, because the only iopoll'ed ops are
reads and writes, which don't need a file table.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It supports both polling and I/O polling. Rename ctx->poll to clearly
show that it's only in I/O poll case.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Calling io_req_complete(req) means that the request is done, and there
is nothing left but to clean it up. That also means that per-op data
after that should not be used, so we're free to reuse it in completion
path, e.g. to store overflow_list as done in this patch.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As for import_iovec(), return !=NULL iovec from io_import_iovec() only
when it should be freed. That includes returning NULL when iovec is
already in req->io, because it should be deallocated by other means,
e.g. inside op handler. After io_setup_async_rw() local iovec to ->io,
just mark it NULL, to follow the idea in io_{read,write} as well.
That's easier to follow, and especially useful if we want to reuse
per-op space for completion data.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: only call kfree() on non-NULL pointer]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Preparing reads/writes for async is a bit tricky. Extract a helper to
not repeat it twice.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't deref req->io->rw every time, but put it in a local variable. This
looks prettier, generates less instructions, and doesn't break alias
analysis.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_kiocb::task_work was de-unionised, and is not planned to be shared
back, because it's too useful and commonly used. Hence, instead of
keeping a separate task_work in struct io_async_rw just reuse
req->task_work.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
send/recv msghdr initialisation works with struct io_async_msghdr, but
pulls the whole struct io_async_ctx for no reason. That complicates it
with composite accessing, e.g. io->msg.
Use and pass the most specific type, which is struct io_async_msghdr.
It is the larget field in union io_async_ctx and doesn't save stack
space, but looks clearer.
The most of the changes are replacing "io->msg." with "iomsg->"
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Every second field in send/recv is called msg, make it a bit more
understandable by renaming ->msg, which is a user provided ptr,
to ->umsg.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
rings_size() sets sq_offset to the total size of the rings (the returned
value which is used for memory allocation). This is wrong: sq array should
be located within the rings, not after them. Set sq_offset to where it
should be.
Fixes: 75b28affdd ("io_uring: allocate the two rings together")
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Hristo Venev <hristo@venev.name>
Cc: io-uring@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge in io_uring-5.8 fixes, as changes/cleanups to how we do locked
mem accounting require a fixup, and only one of the spots are noticed
by git as the other merges cleanly. The flags fix from io_uring-5.8
also causes a merge conflict, the leak fix for recvmsg, the double poll
fix, and the link failure locking fix.
* io_uring-5.8:
io_uring: fix lockup in io_fail_links()
io_uring: fix ->work corruption with poll_add
io_uring: missed req_init_async() for IOSQE_ASYNC
io_uring: always allow drain/link/hardlink/async sqe flags
io_uring: ensure double poll additions work with both request types
io_uring: fix recvmsg memory leak with buffer selection
io_uring: fix not initialised work->flags
io_uring: fix missing msg_name assignment
io_uring: account user memory freed when exit has been queued
io_uring: fix memleak in io_sqe_files_register()
io_uring: fix memleak in __io_sqe_files_update()
io_uring: export cq overflow status to userspace
Signed-off-by: Jens Axboe <axboe@kernel.dk>
req->work might be already initialised by the time it gets into
__io_arm_poll_handler(), which will corrupt it by using fields that are
in an union with req->work. Luckily, the only side effect is missing
put_creds(). Clean req->work before going there.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IOSQE_ASYNC branch of io_queue_sqe() is another place where an
unitialised req->work can be accessed (i.e. prior io_req_init_async()).
Nothing really bad though, it just looses IO_WQ_WORK_CONCURRENT flag.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We currently filter these for timeout_remove/async_cancel/files_update,
but we only should be filtering for fixed file and buffer select. This
also causes a second read of sqe->flags, which isn't needed.
Just check req->flags for the relevant bits. This then allows these
commands to be used in links, for example, like everything else.
Signed-off-by: Daniele Albano <d.albano@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The double poll additions were centered around doing POLL_ADD on file
descriptors that use more than one waitqueue (typically one for read,
one for write) when being polled. However, it can also end up being
triggered for when we use poll triggered retry. For that case, we cannot
safely use req->io, as that could be used by the request type itself.
Add a second io_poll_iocb pointer in the structure we allocate for poll
based retry, and ensure we use the right one from the two paths.
Fixes: 18bceab101 ("io_uring: allow POLL_ADD with double poll_wait() users")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_recvmsg() doesn't free memory allocated for struct io_buffer. This can
causes a leak when used with automatic buffer selection.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
59960b9deb ("io_uring: fix lazy work init") tried to fix missing
io_req_init_async(), but left out work.flags and hash. Do it earlier.
Fixes: 7cdaf587de ("io_uring: avoid whole io_wq_work copy for requests completed inline")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ensure to set msg.msg_name for the async portion of send/recvmsg,
as the header copy will copy to/from it.
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We currently account the memory after the exit work has been run, but
that leaves a gap where a process has closed its ring and until the
memory has been accounted as freed. If the memlocked ulimit is
borderline, then that can introduce spurious setup errors returning
-ENOMEM because the free work hasn't been run yet.
Account this as freed when we close the ring, as not to expose a tiny
gap where setting up a new ring can fail.
Fixes: 85faa7b834 ("io_uring: punt final io_ring_ctx wait-and-free to workqueue")
Cc: stable@vger.kernel.org # v5.7
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We don't use 'ctx' at all in io_sq_thread_drop_mm(), it just works
on the mm of the current task. Drop the argument.
Move io_file_put_work() to where we have the other forward declarations
of functions.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For those applications which are not willing to use io_uring_enter()
to reap and handle cqes, they may completely rely on liburing's
io_uring_peek_cqe(), but if cq ring has overflowed, currently because
io_uring_peek_cqe() is not aware of this overflow, it won't enter
kernel to flush cqes, below test program can reveal this bug:
static void test_cq_overflow(struct io_uring *ring)
{
struct io_uring_cqe *cqe;
struct io_uring_sqe *sqe;
int issued = 0;
int ret = 0;
do {
sqe = io_uring_get_sqe(ring);
if (!sqe) {
fprintf(stderr, "get sqe failed\n");
break;;
}
ret = io_uring_submit(ring);
if (ret <= 0) {
if (ret != -EBUSY)
fprintf(stderr, "sqe submit failed: %d\n", ret);
break;
}
issued++;
} while (ret > 0);
assert(ret == -EBUSY);
printf("issued requests: %d\n", issued);
while (issued) {
ret = io_uring_peek_cqe(ring, &cqe);
if (ret) {
if (ret != -EAGAIN) {
fprintf(stderr, "peek completion failed: %s\n",
strerror(ret));
break;
}
printf("left requets: %d\n", issued);
continue;
}
io_uring_cqe_seen(ring, cqe);
issued--;
printf("left requets: %d\n", issued);
}
}
int main(int argc, char *argv[])
{
int ret;
struct io_uring ring;
ret = io_uring_queue_init(16, &ring, 0);
if (ret) {
fprintf(stderr, "ring setup failed: %d\n", ret);
return 1;
}
test_cq_overflow(&ring);
return 0;
}
To fix this issue, export cq overflow status to userspace by adding new
IORING_SQ_CQ_OVERFLOW flag, then helper functions() in liburing, such as
io_uring_peek_cqe, can be aware of this cq overflow and do flush accordingly.
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's safe to call kfree() with a NULL pointer, but it's also pointless.
Most of the time we don't have any data to free, and at millions of
requests per second, the redundant function call adds noticeable
overhead (about 1.3% of the runtime).
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The "apoll" variable is freed and then used on the next line. We need
to move the free down a few lines.
Fixes: 0be0b0e33b ("io_uring: simplify io_async_task_func()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
First of all don't spin in io_ring_ctx_wait_and_kill() on iopoll.
Requests won't complete faster because of that, but only lengthen
io_uring_release().
The same goes for offloaded cleanup in io_ring_exit_work() -- it
already has waiting loop, don't do blocking active spinning.
For that, pass min=0 into io_iopoll_[try_]reap_events(), so it won't
actively spin. Leave the function if io_do_iopoll() there can't
complete a request to sleep in io_ring_exit_work().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Nobody checks io_iopoll_check()'s output parameter @nr_events.
Remove the parameter and declare it further down the stack.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_iopoll_reap_events() doesn't care about returned valued of
io_iopoll_getevents() and does the same checks for list emptiness
and need_resched(). Just use io_do_iopoll().
io_sq_thread() doesn't check return value as well. It also passes min=0,
so there never be the second iteration inside io_poll_getevents().
Inline it there too.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's not nice to hold @uring_lock for too long io_iopoll_reap_events().
For instance, the lock is needed to publish requests to @poll_list, and
that locks out tasks doing that for no good reason. Loose it
occasionally.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Nobody adjusts *nr_events (number of completed requests) before calling
io_iopoll_getevents(), so the passed @min shouldn't be adjusted as well.
Othewise it can return less than initially asked @min without hitting
need_resched().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
->iopoll() may have completed current request, but instead of reaping
it, io_do_iopoll() just continues with the next request in the list.
As a result it can leave just polled and completed request in the list
up until next syscall. Even outer loop in io_iopoll_getevents() doesn't
help the situation.
E.g. poll_list: req0 -> req1
If req0->iopoll() completed both requests, and @min<=1,
then @req0 will be left behind.
Check whether a req was completed after ->iopoll().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't forget to fill cqe->flags properly in io_submit_flush_completions()
Fixes: a1d7c393c4 ("io_uring: enable READ/WRITE to use deferred completions")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A preparation path, extracts error path into a separate block. It looks
saner then calling req_set_fail_links() after io_put_req_find_next(), even
though it have been working well.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_prep_linked_timeout() sets REQ_F_LINK_TIMEOUT altering refcounting of
the following linked request. After that someone should call
io_queue_linked_timeout(), otherwise a submission reference of the linked
timeout won't be ever dropped.
That's what happens in io_steal_work() if io-wq decides to postpone linked
request with io_wqe_enqueue(). io_queue_linked_timeout() can also be
potentially called twice without synchronisation during re-submission,
e.g. io_rw_resubmit().
There are the rules, whoever did io_prep_linked_timeout() must also call
io_queue_linked_timeout(). To not do it twice, io_prep_linked_timeout()
will return non NULL only for the first call. That's controlled by
REQ_F_LINK_TIMEOUT flag.
Also kill REQ_F_QUEUE_TIMEOUT.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since we now have that in the 5.9 branch, convert the existing users of
task_work_add() to use this new helper.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Provide a helper to run task_work instead of checking and running
manually in a bunch of different spots. While doing so, also move the
task run state setting where we run the task work. Then we can move it
out of the callback helpers. This also helps ensure we only do this once
per task_work list run, not per task_work item.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull in task_work changes from the 5.8 series, as we'll need to apply
the same kind of changes to other parts in the 5.9 branch.
* io_uring-5.8:
io_uring: fix regression with always ignoring signals in io_cqring_wait()
io_uring: use signal based task_work running
task_work: teach task_work_add() to do signal_wake_up()
When switching to TWA_SIGNAL for task_work notifications, we also made
any signal based condition in io_cqring_wait() return -ERESTARTSYS.
This breaks applications that rely on using signals to abort someone
waiting for events.
Check if we have a signal pending because of queued task_work, and
repeat the signal check once we've run the task_work. This provides a
reliable way of telling the two apart.
Additionally, only use TWA_SIGNAL if we are using an eventfd. If not,
we don't have the dependency situation described in the original commit,
and we can get by with just using TWA_RESUME like we previously did.
Fixes: ce593a6c48 ("io_uring: use signal based task_work running")
Cc: stable@vger.kernel.org # v5.7
Reported-by: Andres Freund <andres@anarazel.de>
Tested-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
