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Commit Graph

395 Commits

Author SHA1 Message Date
Jens Axboe
c2f2eb7d2c io_uring: store io_kiocb in wait->private
Store the io_kiocb in the private field instead of the poll entry, this
is in preparation for allowing multiple waitqueues.

No functional changes in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:06:34 -07:00
Pavel Begunkov
5eae861990 io_uring: remove IO_WQ_WORK_CB
IO_WQ_WORK_CB is used only for linked timeouts, which will be armed
before the work setup (i.e. mm, override creds, etc). The setup
shouldn't take long, so it's ok to arm it a bit later and get rid
of IO_WQ_WORK_CB.

Make io-wq call work->func() only once, callbacks will handle the rest.
i.e. the linked timeout handler will do the actual issue. And as a
bonus, it removes an extra indirect call.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:06:29 -07:00
Pavel Begunkov
02d27d8953 io_uring: extract kmsg copy helper
io_recvmsg() and io_sendmsg() duplicate nonblock -EAGAIN finilising
part, so add helper for that.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:41 -07:00
Pavel Begunkov
b0a20349f2 io_uring: clean io_poll_complete
Deduplicate call to io_cqring_fill_event(), plain and easy

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:37 -07:00
Pavel Begunkov
7d67af2c01 io_uring: add splice(2) support
Add support for splice(2).

- output file is specified as sqe->fd, so it's handled by generic code
- hash_reg_file handled by generic code as well
- len is 32bit, but should be fine
- the fd_in is registered file, when SPLICE_F_FD_IN_FIXED is set, which
is a splice flag (i.e. sqe->splice_flags).

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:37 -07:00
Pavel Begunkov
8da11c1994 io_uring: add interface for getting files
Preparation without functional changes. Adds io_get_file(), that allows
to grab files not only into req->file.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:37 -07:00
Pavel Begunkov
bcaec089c5 io_uring: remove req->in_async
req->in_async is not really needed, it only prevents propagation of
@nxt for fast not-blocked submissions. Remove it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:29 -07:00
Pavel Begunkov
deb6dc0544 io_uring: don't do full *prep_worker() from io-wq
io_prep_async_worker() called io_wq_assign_next() do many useless checks:
io_req_work_grab_env() was already called during prep, and @do_hashed
is not ever used. Add io_prep_next_work() -- simplified version, that
can be called io-wq.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:28 -07:00
Pavel Begunkov
5ea6216116 io_uring: don't call work.func from sync ctx
Many operations define custom work.func before getting into an io-wq.
There are several points against:
- it calls io_wq_assign_next() from outside io-wq, that may be confusing
- sync context would go unnecessary through io_req_cancelled()
- prototypes are quite different, so work!=old_work looks strange
- makes async/sync responsibilities fuzzy
- adds extra overhead

Don't call generic path and io-wq handlers from each other, but use
helpers instead

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:24 -07:00
Jens Axboe
e441d1cf20 io_uring: io_accept() should hold on to submit reference on retry
Don't drop an early reference, hang on to it and let the caller drop
it. This makes it behave more like "regular" requests.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:24 -07:00
Jens Axboe
29de5f6a35 io_uring: consider any io_read/write -EAGAIN as final
If the -EAGAIN happens because of a static condition, then a poll
or later retry won't fix it. We must call it again from blocking
condition. Play it safe and ensure that any -EAGAIN condition from read
or write must retry from async context.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:04:24 -07:00
Jens Axboe
d876836204 io_uring: fix 32-bit compatability with sendmsg/recvmsg
We must set MSG_CMSG_COMPAT if we're in compatability mode, otherwise
the iovec import for these commands will not do the right thing and fail
the command with -EINVAL.

Found by running the test suite compiled as 32-bit.

Cc: stable@vger.kernel.org
Fixes: aa1fa28fc7 ("io_uring: add support for recvmsg()")
Fixes: 0fa03c624d ("io_uring: add support for sendmsg()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-27 14:17:49 -07:00
Tobias Klauser
bebdb65e07 io_uring: define and set show_fdinfo only if procfs is enabled
Follow the pattern used with other *_show_fdinfo functions and only
define and use io_uring_show_fdinfo and its helper functions if
CONFIG_PROC_FS is set.

Fixes: 87ce955b24 ("io_uring: add ->show_fdinfo() for the io_uring file descriptor")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-27 06:56:21 -07:00
Jens Axboe
dd3db2a34c io_uring: drop file set ref put/get on switch
Dan reports that he triggered a warning on ring exit doing some testing:

percpu ref (io_file_data_ref_zero) <= 0 (0) after switching to atomic
WARNING: CPU: 3 PID: 0 at lib/percpu-refcount.c:160 percpu_ref_switch_to_atomic_rcu+0xe8/0xf0
Modules linked in:
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.6.0-rc3+ #5648
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
RIP: 0010:percpu_ref_switch_to_atomic_rcu+0xe8/0xf0
Code: e7 ff 55 e8 eb d2 80 3d bd 02 d2 00 00 75 8b 48 8b 55 d8 48 c7 c7 e8 70 e6 81 c6 05 a9 02 d2 00 01 48 8b 75 e8 e8 3a d0 c5 ff <0f> 0b e9 69 ff ff ff 90 55 48 89 fd 53 48 89 f3 48 83 ec 28 48 83
RSP: 0018:ffffc90000110ef8 EFLAGS: 00010292
RAX: 0000000000000045 RBX: 7fffffffffffffff RCX: 0000000000000000
RDX: 0000000000000045 RSI: ffffffff825be7a5 RDI: ffffffff825bc32c
RBP: ffff8881b75eac38 R08: 000000042364b941 R09: 0000000000000045
R10: ffffffff825beb40 R11: ffffffff825be78a R12: 0000607e46005aa0
R13: ffff888107dcdd00 R14: 0000000000000000 R15: 0000000000000009
FS:  0000000000000000(0000) GS:ffff8881b9d80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f49e6a5ea20 CR3: 00000001b747c004 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_core+0x1e4/0x4d0
 __do_softirq+0xdb/0x2f1
 irq_exit+0xa0/0xb0
 smp_apic_timer_interrupt+0x60/0x140
 apic_timer_interrupt+0xf/0x20
 </IRQ>
RIP: 0010:default_idle+0x23/0x170
Code: ff eb ab cc cc cc cc 0f 1f 44 00 00 41 54 55 53 65 8b 2d 10 96 92 7e 0f 1f 44 00 00 e9 07 00 00 00 0f 00 2d 21 d0 51 00 fb f4 <65> 8b 2d f6 95 92 7e 0f 1f 44 00 00 5b 5d 41 5c c3 65 8b 05 e5 95

Turns out that this is due to percpu_ref_switch_to_atomic() only
grabbing a reference to the percpu refcount if it's not already in
atomic mode. io_uring drops a ref and re-gets it when switching back to
percpu mode. We attempt to protect against this with the FFD_F_ATOMIC
bit, but that isn't reliable.

We don't actually need to juggle these refcounts between atomic and
percpu switch, we can just do them when we've switched to atomic mode.
This removes the need for FFD_F_ATOMIC, which wasn't reliable.

Fixes: 05f3fb3c53 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-26 10:53:33 -07:00
Jens Axboe
3a9015988b io_uring: import_single_range() returns 0/-ERROR
Unlike the other core import helpers, import_single_range() returns 0 on
success, not the length imported. This means that links that depend on
the result of non-vec based IORING_OP_{READ,WRITE} that were added for
5.5 get errored when they should not be.

Fixes: 3a6820f2bb ("io_uring: add non-vectored read/write commands")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-26 07:06:57 -07:00
Jens Axboe
2a44f46781 io_uring: pick up link work on submit reference drop
If work completes inline, then we should pick up a dependent link item
in __io_queue_sqe() as well. If we don't do so, we're forced to go async
with that item, which is suboptimal.

This also fixes an issue with io_put_req_find_next(), which always looks
up the next work item. That should only be done if we're dropping the
last reference to the request, to prevent multiple lookups of the same
work item.

Outside of being a fix, this also enables a good cleanup series for 5.7,
where we never have to pass 'nxt' around or into the work handlers.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-26 07:05:30 -07:00
Xiaoguang Wang
bdcd3eab2a io_uring: fix poll_list race for SETUP_IOPOLL|SETUP_SQPOLL
After making ext4 support iopoll method:
  let ext4_file_operations's iopoll method be iomap_dio_iopoll(),
we found fio can easily hang in fio_ioring_getevents() with below fio
job:
    rm -f testfile; sync;
    sudo fio -name=fiotest -filename=testfile -iodepth=128 -thread
-rw=write -ioengine=io_uring  -hipri=1 -sqthread_poll=1 -direct=1
-bs=4k -size=10G -numjobs=8 -runtime=2000 -group_reporting
with IORING_SETUP_SQPOLL and IORING_SETUP_IOPOLL enabled.

There are two issues that results in this hang, one reason is that
when IORING_SETUP_SQPOLL and IORING_SETUP_IOPOLL are enabled, fio
does not use io_uring_enter to get completed events, it relies on
kernel io_sq_thread to poll for completed events.

Another reason is that there is a race: when io_submit_sqes() in
io_sq_thread() submits a batch of sqes, variable 'inflight' will
record the number of submitted reqs, then io_sq_thread will poll for
reqs which have been added to poll_list. But note, if some previous
reqs have been punted to io worker, these reqs will won't be in
poll_list timely. io_sq_thread() will only poll for a part of previous
submitted reqs, and then find poll_list is empty, reset variable
'inflight' to be zero. If app just waits these deferred reqs and does
not wake up io_sq_thread again, then hang happens.

For app that entirely relies on io_sq_thread to poll completed requests,
let io_iopoll_req_issued() wake up io_sq_thread properly when adding new
element to poll_list, and when io_sq_thread prepares to sleep, check
whether poll_list is empty again, if not empty, continue to poll.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-25 08:40:43 -07:00
Jens Axboe
41726c9a50 io_uring: fix personality idr leak
We somehow never free the idr, even though we init it for every ctx.
Free it when the rest of the ring data is freed.

Fixes: 071698e13a ("io_uring: allow registering credentials")
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-24 08:31:51 -07:00
Jens Axboe
193155c8c9 io_uring: handle multiple personalities in link chains
If we have a chain of requests and they don't all use the same
credentials, then the head of the chain will be issued with the
credentails of the tail of the chain.

Ensure __io_queue_sqe() overrides the credentials, if they are different.

Once we do that, we can clean up the creds handling as well, by only
having io_submit_sqe() do the lookup of a personality. It doesn't need
to assign it, since __io_queue_sqe() now always does the right thing.

Fixes: 75c6a03904 ("io_uring: support using a registered personality for commands")
Reported-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-23 19:46:13 -07:00
Xiaoguang Wang
c7849be9cc io_uring: fix __io_iopoll_check deadlock in io_sq_thread
Since commit a3a0e43fd7 ("io_uring: don't enter poll loop if we have
CQEs pending"), if we already events pending, we won't enter poll loop.
In case SETUP_IOPOLL and SETUP_SQPOLL are both enabled, if app has
been terminated and don't reap pending events which are already in cq
ring, and there are some reqs in poll_list, io_sq_thread will enter
__io_iopoll_check(), and find pending events, then return, this loop
will never have a chance to exit.

I have seen this issue in fio stress tests, to fix this issue, let
io_sq_thread call io_iopoll_getevents() with argument 'min' being zero,
and remove __io_iopoll_check().

Fixes: a3a0e43fd7 ("io_uring: don't enter poll loop if we have CQEs pending")
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-22 07:45:03 -07:00
Stefano Garzarella
7143b5ac57 io_uring: prevent sq_thread from spinning when it should stop
This patch drops 'cur_mm' before calling cond_resched(), to prevent
the sq_thread from spinning even when the user process is finished.

Before this patch, if the user process ended without closing the
io_uring fd, the sq_thread continues to spin until the
'sq_thread_idle' timeout ends.

In the worst case where the 'sq_thread_idle' parameter is bigger than
INT_MAX, the sq_thread will spin forever.

Fixes: 6c271ce2f1 ("io_uring: add submission polling")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-21 09:16:10 -07:00
Pavel Begunkov
929a3af90f io_uring: fix use-after-free by io_cleanup_req()
io_cleanup_req() should be called before req->io is freed, and so
shouldn't be after __io_free_req() -> __io_req_aux_free(). Also,
it will be ignored for in io_free_req_many(), which use
__io_req_aux_free().

Place cleanup_req() into __io_req_aux_free().

Fixes: 99bc4c3853 ("io_uring: fix iovec leaks")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-18 17:12:23 -07:00
Dan Carpenter
297a31e3e8 io_uring: remove unnecessary NULL checks
The "kmsg" pointer can't be NULL and we have already dereferenced it so
a check here would be useless.

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-18 11:22:02 -07:00
Pavel Begunkov
7fbeb95d0f io_uring: add missing io_req_cancelled()
fallocate_finish() is missing cancellation check. Add it.
It's safe to do that, as only flags setup and sqe fields copy are done
before it gets into __io_fallocate().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-16 10:09:37 -07:00
Jens Axboe
2ca10259b4 io_uring: prune request from overflow list on flush
Carter reported an issue where he could produce a stall on ring exit,
when we're cleaning up requests that match the given file table. For
this particular test case, a combination of a few things caused the
issue:

- The cq ring was overflown
- The request being canceled was in the overflow list

The combination of the above means that the cq overflow list holds a
reference to the request. The request is canceled correctly, but since
the overflow list holds a reference to it, the final put won't happen.
Since the final put doesn't happen, the request remains in the inflight.
Hence we never finish the cancelation flush.

Fix this by removing requests from the overflow list if we're canceling
them.

Cc: stable@vger.kernel.org # 5.5
Reported-by: Carter Li 李通洲 <carter.li@eoitek.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-13 17:25:01 -07:00
Jens Axboe
b537916ca5 io_uring: retain sockaddr_storage across send/recvmsg async punt
Jonas reports that he sometimes sees -97/-22 error returns from
sendmsg, if it gets punted async. This is due to not retaining the
sockaddr_storage between calls. Include that in the state we copy when
going async.

Cc: stable@vger.kernel.org # 5.3+
Reported-by: Jonas Bonn <jonas@norrbonn.se>
Tested-by: Jonas Bonn <jonas@norrbonn.se>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-09 11:32:10 -07:00
Jens Axboe
6ab231448f io_uring: cancel pending async work if task exits
Normally we cancel all work we track, but for untracked work we could
leave the async worker behind until that work completes. This is totally
fine, but does leave resources pending after the task is gone until that
work completes.

Cancel work that this task queued up when it goes away.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-09 09:55:38 -07:00
Pavel Begunkov
0bdbdd08a8 io_uring: fix openat/statx's filename leak
As in the previous patch, make openat*_prep() and statx_prep() handle
double preparation to avoid resource leakage.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:07:00 -07:00
Pavel Begunkov
5f798beaf3 io_uring: fix double prep iovec leak
Requests may be prepared multiple times with ->io allocated (i.e. async
prepared). Preparation functions don't handle it and forget about
previously allocated resources. This may happen in case of:
- spurious defer_check
- non-head (i.e. async prepared) request executed in sync (via nxt).

Make the handlers check, whether they already allocated resources, which
is true IFF REQ_F_NEED_CLEANUP is set.

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:07:00 -07:00
Pavel Begunkov
a93b33312f io_uring: fix async close() with f_op->flush()
First, io_close() misses filp_close() and io_cqring_add_event(), when
f_op->flush is defined. That's because in this case it will
io_queue_async_work() itself not grabbing files, so the corresponding
chunk in io_close_finish() won't be executed.

Second, when submitted through io_wq_submit_work(), it will do
filp_close() and *_add_event() twice: first inline in io_close(),
and the second one in call to io_close_finish() from io_close().
The second one will also fire, because it was submitted async through
generic path, and so have grabbed files.

And the last nice thing is to remove this weird pilgrimage with checking
work/old_work and casting it to nxt. Just use a helper instead.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:07:00 -07:00
Jens Axboe
0b5faf6ba7 io_uring: allow AT_FDCWD for non-file openat/openat2/statx
Don't just check for dirfd == -1, we should allow AT_FDCWD as well for
relative lookups.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:07:00 -07:00
Jens Axboe
ff002b3018 io_uring: grab ->fs as part of async preparation
This passes it in to io-wq, so it assumes the right fs_struct when
executing async work that may need to do lookups.

Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:07:00 -07:00
Jens Axboe
faac996ccd io_uring: retry raw bdev writes if we hit -EOPNOTSUPP
For non-blocking issue, we set IOCB_NOWAIT in the kiocb. However, on a
raw block device, this yields an -EOPNOTSUPP return, as non-blocking
writes aren't supported. Turn this -EOPNOTSUPP into -EAGAIN, so we retry
from blocking context with IOCB_NOWAIT cleared.

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Pavel Begunkov
8fef80bf56 io_uring: add cleanup for openat()/statx()
openat() and statx() may have allocated ->open.filename, which should be
be put. Add cleanup handlers for them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Pavel Begunkov
99bc4c3853 io_uring: fix iovec leaks
Allocated iovec is freed only in io_{read,write,send,recv)(), and just
leaves it if an error occured. There are plenty of such cases:
- cancellation of non-head requests
- fail grabbing files in __io_queue_sqe()
- set REQ_F_NOWAIT and returning in __io_queue_sqe()

Add REQ_F_NEED_CLEANUP, which will force such requests with custom
allocated resourses go through cleanup handlers on put.

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Pavel Begunkov
e96e977992 io_uring: remove unused struct io_async_open
struct io_async_open is unused, remove it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Stefano Garzarella
63e5d81f72 io_uring: flush overflowed CQ events in the io_uring_poll()
In io_uring_poll() we must flush overflowed CQ events before to
check if there are CQ events available, to avoid missing events.

We call the io_cqring_events() that checks and flushes any overflow
and returns the number of CQ events available.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Jens Axboe
cf3040ca55 io_uring: statx/openat/openat2 don't support fixed files
All of these opcodes take a directory file descriptor. We can't easily
support fixed files for these operations, and the use case for that
probably isn't all that clear (or sensible) anyway.

Disable IOSQE_FIXED_FILE for these operations.

Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:33 -07:00
Pavel Begunkov
1e95081cb5 io_uring: fix deferred req iovec leak
After defer, a request will be prepared, that includes allocating iovec
if needed, and then submitted through io_wq_submit_work() but not custom
handler (e.g. io_rw_async()/io_sendrecv_async()). However, it'll leak
iovec, as it's in io-wq and the code goes as follows:

io_read() {
	if (!io_wq_current_is_worker())
		kfree(iovec);
}

Put all deallocation logic in io_{read,write,send,recv}(), which will
leave the memory, if going async with -EAGAIN.

It also fixes a leak after failed io_alloc_async_ctx() in
io_{recv,send}_msg().

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06 13:58:57 -07:00
Randy Dunlap
e1d85334d6 io_uring: fix 1-bit bitfields to be unsigned
Make bitfields of size 1 bit be unsigned (since there is no room
for the sign bit).
This clears up the sparse warnings:

  CHECK   ../fs/io_uring.c
../fs/io_uring.c:207:50: error: dubious one-bit signed bitfield
../fs/io_uring.c:208:55: error: dubious one-bit signed bitfield
../fs/io_uring.c:209:63: error: dubious one-bit signed bitfield
../fs/io_uring.c:210:54: error: dubious one-bit signed bitfield
../fs/io_uring.c:211:57: error: dubious one-bit signed bitfield

Found by sight and then verified with sparse.

Fixes: 69b3e54613 ("io_uring: change io_ring_ctx bool fields into bit fields")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: io-uring@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06 13:41:00 -07:00
Pavel Begunkov
1cb1edb2f5 io_uring: get rid of delayed mm check
Fail fast if can't grab mm, so past that requests always have an mm
when required. This allows us to remove req->user altogether.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06 12:53:10 -07:00
Linus Torvalds
c1ef57a3a3 io_uring-5.6-2020-02-05
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Merge tag 'io_uring-5.6-2020-02-05' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Some later fixes for io_uring:

   - Small cleanup series from Pavel

   - Belt and suspenders build time check of sqe size and layout
     (Stefan)

   - Addition of ->show_fdinfo() on request of Jann Horn, to aid in
     understanding mapped personalities

   - eventfd recursion/deadlock fix, for both io_uring and aio

   - Fixup for send/recv handling

   - Fixup for double deferral of read/write request

   - Fix for potential double completion event for close request

   - Adjust fadvise advice async/inline behavior

   - Fix for shutdown hang with SQPOLL thread

   - Fix for potential use-after-free of fixed file table"

* tag 'io_uring-5.6-2020-02-05' of git://git.kernel.dk/linux-block:
  io_uring: cleanup fixed file data table references
  io_uring: spin for sq thread to idle on shutdown
  aio: prevent potential eventfd recursion on poll
  io_uring: put the flag changing code in the same spot
  io_uring: iterate req cache backwards
  io_uring: punt even fadvise() WILLNEED to async context
  io_uring: fix sporadic double CQE entry for close
  io_uring: remove extra ->file check
  io_uring: don't map read/write iovec potentially twice
  io_uring: use the proper helpers for io_send/recv
  io_uring: prevent potential eventfd recursion on poll
  eventfd: track eventfd_signal() recursion depth
  io_uring: add BUILD_BUG_ON() to assert the layout of struct io_uring_sqe
  io_uring: add ->show_fdinfo() for the io_uring file descriptor
2020-02-06 06:33:17 +00:00
Jens Axboe
2faf852d1b io_uring: cleanup fixed file data table references
syzbot reports a use-after-free in io_ring_file_ref_switch() when it
tries to switch back to percpu mode. When we put the final reference to
the table by calling percpu_ref_kill_and_confirm(), we don't want the
zero reference to queue async work for flushing the potentially queued
up items. We currently do a few flush_work(), but they merely paper
around the issue, since the work item may not have been queued yet
depending on the when the percpu-ref callback gets run.

Coming into the file unregister, we know we have the ring quiesced.
io_ring_file_ref_switch() can check for whether or not the ref is dying
or not, and not queue anything async at that point. Once the ref has
been confirmed killed, flush any potential items manually.

Reported-by: syzbot+7caeaea49c2c8a591e3d@syzkaller.appspotmail.com
Fixes: 05f3fb3c53 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-04 20:04:18 -07:00
Jens Axboe
df069d80c8 io_uring: spin for sq thread to idle on shutdown
As part of io_uring shutdown, we cancel work that is pending and won't
necessarily complete on its own. That includes requests like poll
commands and timeouts.

If we're using SQPOLL for kernel side submission and we shutdown the
ring immediately after queueing such work, we can race with the sqthread
doing the submission. This means we may miss cancelling some work, which
results in the io_uring shutdown hanging forever.

Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-04 16:48:34 -07:00
Pavel Begunkov
3e577dcd73 io_uring: put the flag changing code in the same spot
Both iocb_flags() and kiocb_set_rw_flags() are inline and modify
kiocb->ki_flags. Place them close, so they can be potentially better
optimised.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Pavel Begunkov
6c8a313469 io_uring: iterate req cache backwards
Grab requests from cache-array from the end, so can get by only
free_reqs.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Jens Axboe
3e69426da2 io_uring: punt even fadvise() WILLNEED to async context
Andres correctly points out that read-ahead can block, if it needs to
read in meta data (or even just through the page cache page allocations).
Play it safe for now and just ensure WILLNEED is also punted to async
context.

While in there, allow the file settings hints from non-blocking
context. They don't need to start/do IO, and we can safely do them
inline.

Fixes: 4840e418c2 ("io_uring: add IORING_OP_FADVISE")
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Jens Axboe
1a417f4e61 io_uring: fix sporadic double CQE entry for close
We punt close to async for the final fput(), but we log the completion
even before that even in that case. We rely on the request not having
a files table assigned to detect what the final async close should do.
However, if we punt the async queue to __io_queue_sqe(), we'll get
->files assigned and this makes io_close_finish() think it should both
close the filp again (which does no harm) AND log a new CQE event for
this request. This causes duplicate CQEs.

Queue the request up for async manually so we don't grab files
needlessly and trigger this condition.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Pavel Begunkov
9250f9ee19 io_uring: remove extra ->file check
It won't ever get into io_prep_rw() when req->file haven't been set in
io_req_set_file(), hence remove the check.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Jens Axboe
5d204bcfa0 io_uring: don't map read/write iovec potentially twice
If we have a read/write that is deferred, we already setup the async IO
context for that request, and mapped it. When we later try and execute
the request and we get -EAGAIN, we don't want to attempt to re-map it.
If we do, we end up with garbage in the iovec, which typically leads
to an -EFAULT or -EINVAL completion.

Cc: stable@vger.kernel.org # 5.5
Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00