Commit Graph

510 Commits

Author SHA1 Message Date
Pavel Begunkov
b55ce73200 io_uring: kill already cached timeout.seq_offset
req->timeout.count and req->io->timeout.seq_offset store the same value,
which is sqe->off. Kill the second one

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-14 19:16:57 -06:00
Pavel Begunkov
22cad1585c io_uring: fix cached_sq_head in io_timeout()
io_timeout() can be executed asynchronously by a worker and without
holding ctx->uring_lock

1. using ctx->cached_sq_head there is racy there
2. it should count events from a moment of timeout's submission, but
not execution

Use req->sequence.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-14 19:16:55 -06:00
Jens Axboe
8e2e1faf28 io_uring: only post events in io_poll_remove_all() if we completed some
syzbot reports this crash:

BUG: unable to handle page fault for address: ffffffffffffffe8
PGD f96e17067 P4D f96e17067 PUD f96e19067 PMD 0
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
CPU: 55 PID: 211750 Comm: trinity-c127 Tainted: G    B        L    5.7.0-rc1-next-20200413 #4
Hardware name: HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 04/12/2017
RIP: 0010:__wake_up_common+0x98/0x290
el/sched/wait.c:87
Code: 40 4d 8d 78 e8 49 8d 7f 18 49 39 fd 0f 84 80 00 00 00 e8 6b bd 2b 00 49 8b 5f 18 45 31 e4 48 83 eb 18 4c 89 ff e8 08 bc 2b 00 <45> 8b 37 41 f6 c6 04 75 71 49 8d 7f 10 e8 46 bd 2b 00 49 8b 47 10
RSP: 0018:ffffc9000adbfaf0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffffffffffe8 RCX: ffffffffaa9636b8
RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffffffffffffffe8
RBP: ffffc9000adbfb40 R08: fffffbfff582c5fd R09: fffffbfff582c5fd
R10: ffffffffac162fe3 R11: fffffbfff582c5fc R12: 0000000000000000
R13: ffff888ef82b0960 R14: ffffc9000adbfb80 R15: ffffffffffffffe8
FS:  00007fdcba4c4740(0000) GS:ffff889033780000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffe8 CR3: 0000000f776a0004 CR4: 00000000001606e0
Call Trace:
 __wake_up_common_lock+0xea/0x150
ommon_lock at kernel/sched/wait.c:124
 ? __wake_up_common+0x290/0x290
 ? lockdep_hardirqs_on+0x16/0x2c0
 __wake_up+0x13/0x20
 io_cqring_ev_posted+0x75/0xe0
v_posted at fs/io_uring.c:1160
 io_ring_ctx_wait_and_kill+0x1c0/0x2f0
l at fs/io_uring.c:7305
 io_uring_create+0xa8d/0x13b0
 ? io_req_defer_prep+0x990/0x990
 ? __kasan_check_write+0x14/0x20
 io_uring_setup+0xb8/0x130
 ? io_uring_create+0x13b0/0x13b0
 ? check_flags.part.28+0x220/0x220
 ? lockdep_hardirqs_on+0x16/0x2c0
 __x64_sys_io_uring_setup+0x31/0x40
 do_syscall_64+0xcc/0xaf0
 ? syscall_return_slowpath+0x580/0x580
 ? lockdep_hardirqs_off+0x1f/0x140
 ? entry_SYSCALL_64_after_hwframe+0x3e/0xb3
 ? trace_hardirqs_off_caller+0x3a/0x150
 ? trace_hardirqs_off_thunk+0x1a/0x1c
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x7fdcb9dd76ed
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 73 01 c3 48 8b 0d 6b 57 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffe7fd4e4f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 00000000000001a9 RCX: 00007fdcb9dd76ed
RDX: fffffffffffffffc RSI: 0000000000000000 RDI: 0000000000005d54
RBP: 00000000000001a9 R08: 0000000e31d3caa7 R09: 0082400004004000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000002
R13: 00007fdcb842e058 R14: 00007fdcba4c46c0 R15: 00007fdcb842e000
Modules linked in: bridge stp llc nfnetlink cn brd vfat fat ext4 crc16 mbcache jbd2 loop kvm_intel kvm irqbypass intel_cstate intel_uncore dax_pmem intel_rapl_perf dax_pmem_core ip_tables x_tables xfs sd_mod tg3 firmware_class libphy hpsa scsi_transport_sas dm_mirror dm_region_hash dm_log dm_mod [last unloaded: binfmt_misc]
CR2: ffffffffffffffe8
---[ end trace f9502383d57e0e22 ]---
RIP: 0010:__wake_up_common+0x98/0x290
Code: 40 4d 8d 78 e8 49 8d 7f 18 49 39 fd 0f 84 80 00 00 00 e8 6b bd 2b 00 49 8b 5f 18 45 31 e4 48 83 eb 18 4c 89 ff e8 08 bc 2b 00 <45> 8b 37 41 f6 c6 04 75 71 49 8d 7f 10 e8 46 bd 2b 00 49 8b 47 10
RSP: 0018:ffffc9000adbfaf0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffffffffffe8 RCX: ffffffffaa9636b8
RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffffffffffffffe8
RBP: ffffc9000adbfb40 R08: fffffbfff582c5fd R09: fffffbfff582c5fd
R10: ffffffffac162fe3 R11: fffffbfff582c5fc R12: 0000000000000000
R13: ffff888ef82b0960 R14: ffffc9000adbfb80 R15: ffffffffffffffe8
FS:  00007fdcba4c4740(0000) GS:ffff889033780000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffe8 CR3: 0000000f776a0004 CR4: 00000000001606e0
Kernel panic - not syncing: Fatal exception
Kernel Offset: 0x29800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
---[ end Kernel panic - not syncing: Fatal exception ]—

which is due to error injection (or allocation failure) preventing the
rings from being setup. On shutdown, we attempt to remove any pending
requests, and for poll request, we call io_cqring_ev_posted() when we've
killed poll requests. However, since the rings aren't setup, we won't
find any poll requests. Make the calling of io_cqring_ev_posted()
dependent on actually having completed requests. This fixes this setup
corner case, and removes spurious calls if we remove poll requests and
don't find any.

Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-13 17:05:14 -06:00
Jens Axboe
2bae047ec9 io_uring: io_async_task_func() should check and honor cancelation
If the request has been marked as canceled, don't try and issue it.
Instead just fill a canceled event and finish the request.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-13 11:22:52 -06:00
Jens Axboe
74ce6ce43d io_uring: check for need to re-wait in polled async handling
We added this for just the regular poll requests in commit a6ba632d2c
("io_uring: retry poll if we got woken with non-matching mask"), we
should do the same for the poll handler used pollable async requests.
Move the re-wait check and arm into a helper, and call it from
io_async_task_func() as well.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-13 11:09:12 -06:00
Jens Axboe
8835758085 io_uring: correct O_NONBLOCK check for splice punt
The splice file punt check uses file->f_mode to check for O_NONBLOCK,
but it should be checking file->f_flags. This leads to punting even
for files that have O_NONBLOCK set, which isn't necessary. This equates
to checking for FMODE_PATH, which will never be set on the fd in
question.

Fixes: 7d67af2c01 ("io_uring: add splice(2) support")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-12 21:16:01 -06:00
Xiaoguang Wang
b1f573bd15 io_uring: restore req->work when canceling poll request
When running liburing test case 'accept', I got below warning:
RED: Invalid credentials
RED: At include/linux/cred.h:285
RED: Specified credentials: 00000000d02474a0
RED: ->magic=4b, put_addr=000000005b4f46e9
RED: ->usage=-1699227648, subscr=-25693
RED: ->*uid = { 256,-25693,-25693,65534 }
RED: ->*gid = { 0,-1925859360,-1789740800,-1827028688 }
RED: ->security is 00000000258c136e
eneral protection fault, probably for non-canonical address 0xdead4ead00000000: 0000 [#1] SMP PTI
PU: 21 PID: 2037 Comm: accept Not tainted 5.6.0+ #318
ardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014
IP: 0010:dump_invalid_creds+0x16f/0x184
ode: 48 8b 83 88 00 00 00 48 3d ff 0f 00 00 76 29 48 89 c2 81 e2 00 ff ff ff 48
81 fa 00 6b 6b 6b 74 17 5b 48 c7 c7 4b b1 10 8e 5d <8b> 50 04 41 5c 8b 30 41 5d
e9 67 e3 04 00 5b 5d 41 5c 41 5d c3 0f
SP: 0018:ffffacc1039dfb38 EFLAGS: 00010087
AX: dead4ead00000000 RBX: ffff9ba39319c100 RCX: 0000000000000007
DX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e10b14b
BP: ffffffff8e108476 R08: 0000000000000000 R09: 0000000000000001
10: 0000000000000000 R11: ffffacc1039df9e5 R12: 000000009552b900
13: 000000009319c130 R14: ffff9ba39319c100 R15: 0000000000000246
S:  00007f96b2bfc4c0(0000) GS:ffff9ba39f340000(0000) knlGS:0000000000000000
S:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
R2: 0000000000401870 CR3: 00000007db7a4000 CR4: 00000000000006e0
all Trace:
__invalid_creds+0x48/0x4a
__io_req_aux_free+0x2e8/0x3b0
? io_poll_remove_one+0x2a/0x1d0
__io_free_req+0x18/0x200
io_free_req+0x31/0x350
io_poll_remove_one+0x17f/0x1d0
io_poll_cancel.isra.80+0x6c/0x80
io_async_find_and_cancel+0x111/0x120
io_issue_sqe+0x181/0x10e0
? __lock_acquire+0x552/0xae0
? lock_acquire+0x8e/0x310
? fs_reclaim_acquire.part.97+0x5/0x30
__io_queue_sqe.part.100+0xc4/0x580
? io_submit_sqes+0x751/0xbd0
? rcu_read_lock_sched_held+0x32/0x40
io_submit_sqes+0x9ba/0xbd0
? __x64_sys_io_uring_enter+0x2b2/0x460
? __x64_sys_io_uring_enter+0xaf/0x460
? find_held_lock+0x2d/0x90
? __x64_sys_io_uring_enter+0x111/0x460
__x64_sys_io_uring_enter+0x2d7/0x460
do_syscall_64+0x5a/0x230
entry_SYSCALL_64_after_hwframe+0x49/0xb3

After looking into codes, it turns out that this issue is because we didn't
restore the req->work, which is changed in io_arm_poll_handler(), req->work
is a union with below struct:
	struct {
		struct callback_head	task_work;
		struct hlist_node	hash_node;
		struct async_poll	*apoll;
	};
If we forget to restore, members in struct io_wq_work would be invalid,
restore the req->work to fix this issue.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

Get rid of not needed 'need_restore' variable.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-12 08:46:50 -06:00
Pavel Begunkov
ef4ff58110 io_uring: move all request init code in one place
Requests initialisation is scattered across several functions, namely
io_init_req(), io_submit_sqes(), io_submit_sqe(). Put it
in io_init_req() for better data locality and code clarity.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-12 08:46:50 -06:00
Pavel Begunkov
dea3b49c7f io_uring: keep all sqe->flags in req->flags
It's a good idea to not read sqe->flags twice, as it's prone to security
bugs. Instead of passing it around, embeed them in req->flags. It's
already so except for IOSQE_IO_LINK.
1. rename former REQ_F_LINK -> REQ_F_LINK_HEAD
2. introduce and copy REQ_F_LINK, which mimics IO_IOSQE_LINK

And leave req_set_fail_links() using new REQ_F_LINK, because it's more
sensible.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-12 08:46:49 -06:00
Pavel Begunkov
1d4240cc9e io_uring: early submission req fail code
Having only one place for cleaning up a request after a link assembly/
submission failure will play handy in the future. At least it allows
to remove duplicated cleanup sequence.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-12 08:46:44 -06:00
Pavel Begunkov
bf9c2f1cdc io_uring: track mm through current->mm
As a preparation for extracting request init bits, remove self-coded mm
tracking from io_submit_sqes(), but rely on current->mm. It's more
convenient, than passing this piece of state in other functions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-12 08:46:30 -06:00
Pavel Begunkov
dccc587f6c io_uring: remove obsolete @mm_fault
If io_submit_sqes() can't grab an mm, it fails and exits right away.
There is no need to track the fact of the failure. Remove @mm_fault.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-12 08:46:30 -06:00
Jens Axboe
85faa7b834 io_uring: punt final io_ring_ctx wait-and-free to workqueue
We can't reliably wait in io_ring_ctx_wait_and_kill(), since the
task_works list isn't ordered (in fact it's LIFO ordered). We could
either fix this with a separate task_works list for io_uring work, or
just punt the wait-and-free to async context. This ensures that
task_work that comes in while we're shutting down is processed
correctly. If we don't go async, we could have work past the fput()
work for the ring that depends on work that won't be executed until
after we're done with the wait-and-free. But as this operation is
blocking, it'll never get a chance to run.

This was reproduced with hundreds of thousands of sockets running
memcached, haven't been able to reproduce this synthetically.

Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-09 18:45:27 -06:00
Pavel Begunkov
c398ecb3d6 io_uring: fix fs cleanup on cqe overflow
If completion queue overflow occurs, __io_cqring_fill_event() will
update req->cflags, which is in a union with req->work and happens to
be aliased to req->work.fs. Following io_free_req() ->
io_req_work_drop_env() may get a bunch of different problems (miscount
fs->users, segfault, etc) on cleaning @fs.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-09 09:38:18 -06:00
Pavel Begunkov
9c280f9087 io_uring: don't read user-shared sqe flags twice
Don't re-read userspace-shared sqe->flags, it can be exploited.
sqe->flags are copied into req->flags in io_submit_sqe(), check them
there instead.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-08 09:26:51 -06:00
Pavel Begunkov
0553b8bda8 io_uring: remove req init from io_get_req()
io_get_req() do two different things: io_kiocb allocation and
initialisation. Move init part out of it and rename into
io_alloc_req(). It's simpler this way and also have better data
locality.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-08 09:26:28 -06:00
Pavel Begunkov
b1e50e549b io_uring: alloc req only after getting sqe
As io_get_sqe() split into 2 stage get/consume, get an sqe before
allocating io_kiocb, so no free_req*() for a failure case is needed,
and inline back __io_req_do_free(), which has only 1 user.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-08 09:26:16 -06:00
Pavel Begunkov
709b302fad io_uring: simplify io_get_sqring
Make io_get_sqring() care only about sqes themselves, not initialising
the io_kiocb. Also, split it into get + consume, that will be helpful in
the future.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-08 09:25:18 -06:00
Xiaoguang Wang
45097daea2 io_uring: do not always copy iovec in io_req_map_rw()
In io_read_prep() or io_write_prep(), io_req_map_rw() takes
struct io_async_rw's fast_iov as argument to call io_import_iovec(),
and if io_import_iovec() uses struct io_async_rw's fast_iov as
valid iovec array, later indeed io_req_map_rw() does not need
to do the memcpy operation, because they are same pointers.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-08 09:23:42 -06:00
Jens Axboe
08a1d26eb8 io_uring: ensure openat sets O_LARGEFILE if needed
OPENAT2 correctly sets O_LARGEFILE if it has to, but that escaped the
OPENAT opcode. Dmitry reports that his test case that compares openat()
and IORING_OP_OPENAT sees failures on large files:

*** sync openat
openat succeeded
sync write at offset 0
write succeeded
sync write at offset 4294967296
write succeeded

*** sync openat
openat succeeded
io_uring write at offset 0
write succeeded
io_uring write at offset 4294967296
write succeeded

*** io_uring openat
openat succeeded
sync write at offset 0
write succeeded
sync write at offset 4294967296
write failed: File too large

*** io_uring openat
openat succeeded
io_uring write at offset 0
write succeeded
io_uring write at offset 4294967296
write failed: File too large

Ensure we set O_LARGEFILE, if force_o_largefile() is true.

Cc: stable@vger.kernel.org # v5.6
Fixes: 15b71abe7b ("io_uring: add support for IORING_OP_OPENAT")
Reported-by: Dmitry Kadashev <dkadashev@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-08 09:20:54 -06:00
Xiaoguang Wang
f7fe934686 io_uring: initialize fixed_file_data lock
syzbot reports below warning:
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 7099 Comm: syz-executor897 Not tainted 5.6.0-next-20200406-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+0x188/0x20d lib/dump_stack.c:118
 assign_lock_key kernel/locking/lockdep.c:913 [inline]
 register_lock_class+0x1664/0x1760 kernel/locking/lockdep.c:1225
 __lock_acquire+0x104/0x4e00 kernel/locking/lockdep.c:4223
 lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4923
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
 io_sqe_files_register fs/io_uring.c:6599 [inline]
 __io_uring_register+0x1fe8/0x2f00 fs/io_uring.c:8001
 __do_sys_io_uring_register fs/io_uring.c:8081 [inline]
 __se_sys_io_uring_register fs/io_uring.c:8063 [inline]
 __x64_sys_io_uring_register+0x192/0x560 fs/io_uring.c:8063
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x440289
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffff1bbf558 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440289
RDX: 0000000020000280 RSI: 0000000000000002 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000401b10
R13: 0000000000401ba0 R14: 0000000000000000 R15: 0000000000000000

Initialize struct fixed_file_data's lock to fix this issue.

Reported-by: syzbot+e6eeca4a035da76b3065@syzkaller.appspotmail.com
Fixes: 0558955373 ("io_uring: refactor file register/unregister/update handling")
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-07 09:45:51 -06:00
Colin Ian King
211fea18a7 io_uring: remove redundant variable pointer nxt and io_wq_assign_next call
An earlier commit "io_uring: remove @nxt from handlers" removed the
setting of pointer nxt and now it is always null, hence the non-null
check and call to io_wq_assign_next is redundant and can be removed.

Addresses-Coverity: ("'Constant' variable guard")
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-07 09:45:33 -06:00
Pavel Begunkov
48bdd849e9 io_uring: fix ctx refcounting in io_submit_sqes()
If io_get_req() fails, it drops a ref. Then, awhile keeping @submitted
unmodified, io_submit_sqes() breaks the loop and puts @nr - @submitted
refs. For each submitted req a ref is dropped in io_put_req() and
friends. So, for @nr taken refs there will be
(@nr - @submitted + @submitted + 1) dropped.

Remove ctx refcounting from io_get_req(), that at the same time makes
it clearer.

Fixes: 2b85edfc0c ("io_uring: batch getting pcpu references")
Cc: stable@vger.kernel.org # v5.6
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-05 16:23:48 -06:00
Bijan Mottahedeh
581f981034 io_uring: process requests completed with -EAGAIN on poll list
A request that completes with an -EAGAIN result after it has been added
to the poll list, will not be removed from that list in io_do_iopoll()
because the f_op->iopoll() will not succeed for that request.

Maintain a retryable local list similar to the done list, and explicity
reissue requests with an -EAGAIN result.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-03 14:55:39 -06:00
Jens Axboe
c336e992cb io_uring: remove bogus RLIMIT_NOFILE check in file registration
We already checked this limit when the file was opened, and we keep it
open in the file table. Hence when we added unit_inflight to the count
we want to register, we're doubly accounting these files. This results
in -EMFILE for file registration, if we're at half the limit.

Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-03 13:56:44 -06:00
Jens Axboe
aa96bf8a9e io_uring: use io-wq manager as backup task if task is exiting
If the original task is (or has) exited, then the task work will not get
queued properly. Allow for using the io-wq manager task to queue this
work for execution, and ensure that the io-wq manager notices and runs
this work if woken up (or exiting).

Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-03 11:35:57 -06:00
Jens Axboe
3537b6a7c6 io_uring: grab task reference for poll requests
We can have a task exit if it's not the owner of the ring. Be safe and
grab an actual reference to it, to avoid a potential use-after-free.

Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-03 11:35:57 -06:00
Jens Axboe
a6ba632d2c io_uring: retry poll if we got woken with non-matching mask
If we get woken and the poll doesn't match our mask, re-add the task
to the poll waitqueue and try again instead of completing the request
with a mask of 0.

Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-03 11:35:48 -06:00
Hillf Danton
10bea96dcc io_uring: add missing finish_wait() in io_sq_thread()
Add it to pair with prepare_to_wait() in an attempt to avoid
anything weird in the field.

Fixes: b41e98524e ("io_uring: add per-task callback handler")
Reported-by: syzbot+0c3370f235b74b3cfd97@syzkaller.appspotmail.com
Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-01 07:02:55 -06:00
Xiaoguang Wang
0558955373 io_uring: refactor file register/unregister/update handling
While diving into io_uring fileset register/unregister/update codes, we
found one bug in the fileset update handling. io_uring fileset update
use a percpu_ref variable to check whether we can put the previously
registered file, only when the refcnt of the perfcpu_ref variable
reaches zero, can we safely put these files. But this doesn't work so
well. If applications always issue requests continually, this
perfcpu_ref will never have an chance to reach zero, and it'll always be
in atomic mode, also will defeat the gains introduced by fileset
register/unresiger/update feature, which are used to reduce the atomic
operation overhead of fput/fget.

To fix this issue, while applications do IORING_REGISTER_FILES or
IORING_REGISTER_FILES_UPDATE operations, we allocate a new percpu_ref
and kill the old percpu_ref, new requests will use the new percpu_ref.
Once all previous old requests complete, old percpu_refs will be dropped
and registered files will be put safely.

Link: https://lore.kernel.org/io-uring/5a8dac33-4ca2-4847-b091-f7dcd3ad0ff3@linux.alibaba.com/T/#t
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-31 08:47:54 -06:00
Linus Torvalds
e59cd88028 for-5.7/io_uring-2020-03-29
-----BEGIN PGP SIGNATURE-----
 
 iQJEBAABCAAuFiEEwPw5LcreJtl1+l5K99NY+ylx4KYFAl6BJEMQHGF4Ym9lQGtl
 cm5lbC5kawAKCRD301j7KXHgpie7D/9gN4zhykYDfcgamfxMtTbpla2PdTnWoJxP
 fjy/Nx2FySakmccaiCGQSQ1rzD1L67UQkJgEH6hPTomJvA4FaOmJ+ZSaExMy55LH
 ZT+nD3zQ9SCuA0DEpfxbsCP1tbnoXSMQNt8Tyh0x8PAoxp5bI0eRczOju1QWLWTS
 tjBEMZNipN6krrV9RPWT0S5Z31/yGr/sXprCSHFV9Ypzwrx58Tj2i6F9gR7FVbLs
 nV2/O8taEn0sMQIz8TVHKol/TBalluGrC4M/bOeS3faP3BPN4TT24Gtc0LAKEibk
 F49/SX7FzwhOdl43Bdkbe2bbL86p+zOLSf0IMBwMm0DJl4aiOljRUYTSYRolgGgm
 Ebw9QhemTwbxxeD2nEriA4EAeYvTx69RDlN2eVilwwfJ48Xz9fVm3GNYG7LISeON
 k3/TyZOBQH2SZ2Hc3oF2Mq9j1UPHXZHUUsUNlNcN+aM9SFHcWkRi6xZWemTJHJZ4
 zFss5RZHo0+RLBa8rrx8xaO8iWrc73+FuRhr9eSsmyPIj+OZ4ezEFRRRHwtk2fgv
 dZvD413AyCI1c+3LlBusESMsrtXyY8p9O9buNTzHy3ZUtHe0ERmYV2m/a83A5pXo
 Kia/5aJbPIC61bAkCCkiVo+W9OASJ6o5+3CXl5sM9lGTbDXjcofzewmd+RHPestx
 xVbzeR9UIw==
 =bYLJ
 -----END PGP SIGNATURE-----

Merge tag 'for-5.7/io_uring-2020-03-29' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Here are the io_uring changes for this merge window. Light on new
  features this time around (just splice + buffer selection), lots of
  cleanups, fixes, and improvements to existing support. In particular,
  this contains:

   - Cleanup fixed file update handling for stack fallback (Hillf)

   - Re-work of how pollable async IO is handled, we no longer require
     thread offload to handle that. Instead we rely using poll to drive
     this, with task_work execution.

   - In conjunction with the above, allow expendable buffer selection,
     so that poll+recv (for example) no longer has to be a split
     operation.

   - Make sure we honor RLIMIT_FSIZE for buffered writes

   - Add support for splice (Pavel)

   - Linked work inheritance fixes and optimizations (Pavel)

   - Async work fixes and cleanups (Pavel)

   - Improve io-wq locking (Pavel)

   - Hashed link write improvements (Pavel)

   - SETUP_IOPOLL|SETUP_SQPOLL improvements (Xiaoguang)"

* tag 'for-5.7/io_uring-2020-03-29' of git://git.kernel.dk/linux-block: (54 commits)
  io_uring: cleanup io_alloc_async_ctx()
  io_uring: fix missing 'return' in comment
  io-wq: handle hashed writes in chains
  io-uring: drop 'free_pfile' in struct io_file_put
  io-uring: drop completion when removing file
  io_uring: Fix ->data corruption on re-enqueue
  io-wq: close cancel gap for hashed linked work
  io_uring: make spdxcheck.py happy
  io_uring: honor original task RLIMIT_FSIZE
  io-wq: hash dependent work
  io-wq: split hashing and enqueueing
  io-wq: don't resched if there is no work
  io-wq: remove duplicated cancel code
  io_uring: fix truncated async read/readv and write/writev retry
  io_uring: dual license io_uring.h uapi header
  io_uring: io_uring_enter(2) don't poll while SETUP_IOPOLL|SETUP_SQPOLL enabled
  io_uring: Fix unused function warnings
  io_uring: add end-of-bits marker and build time verify it
  io_uring: provide means of removing buffers
  io_uring: add IOSQE_BUFFER_SELECT support for IORING_OP_RECVMSG
  ...
2020-03-30 12:18:49 -07:00
Xiaoguang Wang
3d9932a8b2 io_uring: cleanup io_alloc_async_ctx()
Cleanup io_alloc_async_ctx() a bit, add a new __io_alloc_async_ctx(),
so io_setup_async_rw() won't need to check whether async_ctx is true
or false again.

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-27 08:54:06 -06:00
Chucheng Luo
bff6035d0c io_uring: fix missing 'return' in comment
The missing 'return' work may make it hard for other developers to
understand it.

Signed-off-by: Chucheng Luo <luochucheng@vivo.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-24 21:46:36 -06:00
Hillf Danton
a5318d3cdf io-uring: drop 'free_pfile' in struct io_file_put
Sync removal of file is only used in case of a GFP_KERNEL kmalloc
failure at the cost of io_file_put::done and work flush, while a
glich like it can be handled at the call site without too much pain.

That said, what is proposed is to drop sync removing of file, and
the kink in neck as well.

Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-23 09:22:15 -06:00
Hillf Danton
4afdb733b1 io-uring: drop completion when removing file
A case of task hung was reported by syzbot,

INFO: task syz-executor975:9880 blocked for more than 143 seconds.
      Not tainted 5.6.0-rc6-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor975 D27576  9880   9878 0x80004000
Call Trace:
 schedule+0xd0/0x2a0 kernel/sched/core.c:4154
 schedule_timeout+0x6db/0xba0 kernel/time/timer.c:1871
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common kernel/sched/completion.c:115 [inline]
 wait_for_completion+0x26a/0x3c0 kernel/sched/completion.c:136
 io_queue_file_removal+0x1af/0x1e0 fs/io_uring.c:5826
 __io_sqe_files_update.isra.0+0x3a1/0xb00 fs/io_uring.c:5867
 io_sqe_files_update fs/io_uring.c:5918 [inline]
 __io_uring_register+0x377/0x2c00 fs/io_uring.c:7131
 __do_sys_io_uring_register fs/io_uring.c:7202 [inline]
 __se_sys_io_uring_register fs/io_uring.c:7184 [inline]
 __x64_sys_io_uring_register+0x192/0x560 fs/io_uring.c:7184
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

and bisect pointed to 05f3fb3c53 ("io_uring: avoid ring quiesce for
fixed file set unregister and update").

It is down to the order that we wait for work done before flushing it
while nobody is likely going to wake us up.

We can drop that completion on stack as flushing work itself is a sync
operation we need and no more is left behind it.

To that end, io_file_put::done is re-used for indicating if it can be
freed in the workqueue worker context.

Reported-and-Inspired-by: syzbot <syzbot+538d1957ce178382a394@syzkaller.appspotmail.com>
Signed-off-by: Hillf Danton <hdanton@sina.com>

Rename ->done to ->free_pfile

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-23 09:21:06 -06:00
Pavel Begunkov
18a542ff19 io_uring: Fix ->data corruption on re-enqueue
work->data and work->list are shared in union. io_wq_assign_next() sets
->data if a req having a linked_timeout, but then io-wq may want to use
work->list, e.g. to do re-enqueue of a request, so corrupting ->data.

->data is not necessary, just remove it and extract linked_timeout
through @link_list.

Fixes: 60cf46ae60 ("io-wq: hash dependent work")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-22 19:31:27 -06:00
Jens Axboe
4ed734b0d0 io_uring: honor original task RLIMIT_FSIZE
With the previous fixes for number of files open checking, I added some
debug code to see if we had other spots where we're checking rlimit()
against the async io-wq workers. The only one I found was file size
checking, which we should also honor.

During write and fallocate prep, store the max file size and override
that for the current ask if we're in io-wq worker context.

Cc: stable@vger.kernel.org # 5.1+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-20 11:41:23 -06:00
Jens Axboe
09952e3e78 io_uring: make sure accept honor rlimit nofile
Just like commit 4022e7af86, this fixes the fact that
IORING_OP_ACCEPT ends up using get_unused_fd_flags(), which checks
current->signal->rlim[] for limits.

Add an extra argument to __sys_accept4_file() that allows us to pass
in the proper nofile limit, and grab it at request prep time.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-20 08:48:36 -06:00
Jens Axboe
4022e7af86 io_uring: make sure openat/openat2 honor rlimit nofile
Dmitry reports that a test case shows that io_uring isn't honoring a
modified rlimit nofile setting. get_unused_fd_flags() checks the task
signal->rlimi[] for the limits. As this isn't easily inheritable,
provide a __get_unused_fd_flags() that takes the value instead. Then we
can grab it when the request is prepared (from the original task), and
pass that in when we do the async part part of the open.

Reported-by: Dmitry Kadashev <dkadashev@gmail.com>
Tested-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-20 08:47:27 -06:00
Pavel Begunkov
8766dd516c io-wq: split hashing and enqueueing
It's a preparation patch removing io_wq_enqueue_hashed(), which
now should be done by io_wq_hash_work() + io_wq_enqueue().

Also, set hash value for dependant works, and do it as late as possible,
because req->file can be unavailable before. This hash will be ignored
by io-wq.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-14 17:02:28 -06:00
Pavel Begunkov
f1d96a8fcb io_uring: NULL-deref for IOSQE_{ASYNC,DRAIN}
Processing links, io_submit_sqe() prepares requests, drops sqes, and
passes them with sqe=NULL to io_queue_sqe(). There IOSQE_DRAIN and/or
IOSQE_ASYNC requests will go through the same prep, which doesn't expect
sqe=NULL and fail with NULL pointer deference.

Always do full prepare including io_alloc_async_ctx() for linked
requests, and then it can skip the second preparation.

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-14 16:57:41 -06:00
Jens Axboe
3f9d64415f io_uring: fix truncated async read/readv and write/writev retry
Ensure we keep the truncated value, if we did truncate it. If not, we
might read/write more than the registered buffer size.

Also for retry, ensure that we return the truncated mapped value for
the vectorized versions of the read/write commands.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-11 12:29:15 -06:00
Xiaoguang Wang
32b2244a84 io_uring: io_uring_enter(2) don't poll while SETUP_IOPOLL|SETUP_SQPOLL enabled
When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, applications don't need
to do io completion events polling again, they can rely on io_sq_thread to do
polling work, which can reduce cpu usage and uring_lock contention.

I modify fio io_uring engine codes a bit to evaluate the performance:
static int fio_ioring_getevents(struct thread_data *td, unsigned int min,
                        continue;
                }

-               if (!o->sqpoll_thread) {
+               if (o->sqpoll_thread && o->hipri) {
                        r = io_uring_enter(ld, 0, actual_min,
                                                IORING_ENTER_GETEVENTS);
                        if (r < 0) {

and use "fio  -name=fiotest -filename=/dev/nvme0n1 -iodepth=$depth -thread
-rw=read -ioengine=io_uring  -hipri=1 -sqthread_poll=1  -direct=1 -bs=4k
-size=10G -numjobs=1  -time_based -runtime=120"

original codes
--------------------------------------------------------------------
iodepth       |        4 |        8 |       16 |       32 |       64
bw            | 1133MB/s | 1519MB/s | 2090MB/s | 2710MB/s | 3012MB/s
fio cpu usage |     100% |     100% |     100% |     100% |     100%
--------------------------------------------------------------------

with patch
--------------------------------------------------------------------
iodepth       |        4 |        8 |       16 |       32 |       64
bw            | 1196MB/s | 1721MB/s | 2351MB/s | 2977MB/s | 3357MB/s
fio cpu usage |    63.8% |   74.4%% |    81.1% |    83.7% |    82.4%
--------------------------------------------------------------------
bw improve    |     5.5% |    13.2% |    12.3% |     9.8% |    11.5%
--------------------------------------------------------------------

From above test results, we can see that bw has above 5.5%~13%
improvement, and fio process's cpu usage also drops much. Note this
won't improve io_sq_thread's cpu usage when SETUP_IOPOLL|SETUP_SQPOLL
are both enabled, in this case, io_sq_thread always has 100% cpu usage.
I think this patch will be friendly to applications which will often use
io_uring_wait_cqe() or similar from liburing.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-11 07:14:12 -06:00
YueHaibing
469956e853 io_uring: Fix unused function warnings
If CONFIG_NET is not set, gcc warns:

fs/io_uring.c:3110:12: warning: io_setup_async_msg defined but not used [-Wunused-function]
 static int io_setup_async_msg(struct io_kiocb *req,
            ^~~~~~~~~~~~~~~~~~

There are many funcions wraped by CONFIG_NET, move them
together to simplify code, also fix this warning.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>

Minor tweaks.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-10 09:12:56 -06:00
Jens Axboe
84557871f2 io_uring: add end-of-bits marker and build time verify it
Not easy to tell if we're going over the size of bits we can shove
in req->flags, so add an end-of-bits marker and a BUILD_BUG_ON()
check for it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-10 09:12:56 -06:00
Jens Axboe
067524e914 io_uring: provide means of removing buffers
We have IORING_OP_PROVIDE_BUFFERS, but the only way to remove buffers
is to trigger IO on them. The usual case of shrinking a buffer pool
would be to just not replenish the buffers when IO completes, and
instead just free it. But it may be nice to have a way to manually
remove a number of buffers from a given group, and
IORING_OP_REMOVE_BUFFERS provides that functionality.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-10 09:12:56 -06:00
Jens Axboe
52de1fe122 io_uring: add IOSQE_BUFFER_SELECT support for IORING_OP_RECVMSG
Like IORING_OP_READV, this is limited to supporting just a single
segment in the iovec passed in.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-10 09:12:51 -06:00
Jens Axboe
4d954c258a io_uring: add IOSQE_BUFFER_SELECT support for IORING_OP_READV
This adds support for the vectored read. This is limited to supporting
just 1 segment in the iov, and is provided just for convenience for
applications that use IORING_OP_READV already.

The iov helpers will be used for IORING_OP_RECVMSG as well.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-10 09:12:48 -06:00
Jens Axboe
bcda7baaa3 io_uring: support buffer selection for OP_READ and OP_RECV
If a server process has tons of pending socket connections, generally
it uses epoll to wait for activity. When the socket is ready for reading
(or writing), the task can select a buffer and issue a recv/send on the
given fd.

Now that we have fast (non-async thread) support, a task can have tons
of pending reads or writes pending. But that means they need buffers to
back that data, and if the number of connections is high enough, having
them preallocated for all possible connections is unfeasible.

With IORING_OP_PROVIDE_BUFFERS, an application can register buffers to
use for any request. The request then sets IOSQE_BUFFER_SELECT in the
sqe, and a given group ID in sqe->buf_group. When the fd becomes ready,
a free buffer from the specified group is selected. If none are
available, the request is terminated with -ENOBUFS. If successful, the
CQE on completion will contain the buffer ID chosen in the cqe->flags
member, encoded as:

	(buffer_id << IORING_CQE_BUFFER_SHIFT) | IORING_CQE_F_BUFFER;

Once a buffer has been consumed by a request, it is no longer available
and must be registered again with IORING_OP_PROVIDE_BUFFERS.

Requests need to support this feature. For now, IORING_OP_READ and
IORING_OP_RECV support it. This is checked on SQE submission, a CQE with
res == -EOPNOTSUPP will be posted if attempted on unsupported requests.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-10 09:12:45 -06:00
Jens Axboe
ddf0322db7 io_uring: add IORING_OP_PROVIDE_BUFFERS
IORING_OP_PROVIDE_BUFFERS uses the buffer registration infrastructure to
support passing in an addr/len that is associated with a buffer ID and
buffer group ID. The group ID is used to index and lookup the buffers,
while the buffer ID can be used to notify the application which buffer
in the group was used. The addr passed in is the starting buffer address,
and length is each buffer length. A number of buffers to add with can be
specified, in which case addr is incremented by length for each addition,
and each buffer increments the buffer ID specified.

No validation is done of the buffer ID. If the application provides
buffers within the same group with identical buffer IDs, then it'll have
a hard time telling which buffer ID was used. The only restriction is
that the buffer ID can be a max of 16-bits in size, so USHRT_MAX is the
maximum ID that can be used.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-10 09:12:14 -06:00
Jens Axboe
805b13adde io_uring: ensure RCU callback ordering with rcu_barrier()
After more careful studying, Paul informs me that we cannot rely on
ordering of RCU callbacks in the way that the the tagged commit did.
The current construct looks like this:

	void C(struct rcu_head *rhp)
	{
		do_something(rhp);
		call_rcu(&p->rh, B);
	}

	call_rcu(&p->rh, A);
	call_rcu(&p->rh, C);

and we're relying on ordering between A and B, which isn't guaranteed.
Make this explicit instead, and have a work item issue the rcu_barrier()
to ensure that A has run before we manually execute B.

While thorough testing never showed this issue, it's dependent on the
per-cpu load in terms of RCU callbacks. The updated method simplifies
the code as well, and eliminates the need to maintain an rcu_head in
the fileset data.

Fixes: c1e2148f8e ("io_uring: free fixed_file_data after RCU grace period")
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-08 20:07:28 -06:00
Pavel Begunkov
f0e20b8943 io_uring: fix lockup with timeouts
There is a recipe to deadlock the kernel: submit a timeout sqe with a
linked_timeout (e.g.  test_single_link_timeout_ception() from liburing),
and SIGKILL the process.

Then, io_kill_timeouts() takes @ctx->completion_lock, but the timeout
isn't flagged with REQ_F_COMP_LOCKED, and will try to double grab it
during io_put_free() to cancel the linked timeout. Probably, the same
can happen with another io_kill_timeout() call site, that is
io_commit_cqring().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-07 08:35:56 -07:00
Jens Axboe
c1e2148f8e io_uring: free fixed_file_data after RCU grace period
The percpu refcount protects this structure, and we can have an atomic
switch in progress when exiting. This makes it unsafe to just free the
struct normally, and can trigger the following KASAN warning:

BUG: KASAN: use-after-free in percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
Read of size 1 at addr ffff888181a19a30 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc4+ #5747
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Call Trace:
 <IRQ>
 dump_stack+0x76/0xa0
 print_address_description.constprop.0+0x3b/0x60
 ? percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
 ? percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
 __kasan_report.cold+0x1a/0x3d
 ? percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
 percpu_ref_switch_to_atomic_rcu+0xfa/0x1b0
 rcu_core+0x370/0x830
 ? percpu_ref_exit+0x50/0x50
 ? rcu_note_context_switch+0x7b0/0x7b0
 ? run_rebalance_domains+0x11d/0x140
 __do_softirq+0x10a/0x3e9
 irq_exit+0xd5/0xe0
 smp_apic_timer_interrupt+0x86/0x200
 apic_timer_interrupt+0xf/0x20
 </IRQ>
RIP: 0010:default_idle+0x26/0x1f0

Fix this by punting the final exit and free of the struct to RCU, then
we know that it's safe to do so. Jann suggested the approach of using a
double rcu callback to achieve this. It's important that we do a nested
call_rcu() callback, as otherwise the free could be ordered before the
atomic switch, even if the latter was already queued.

Reported-by: syzbot+e017e49c39ab484ac87a@syzkaller.appspotmail.com
Suggested-by: Jann Horn <jannh@google.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-06 10:15:21 -07:00
Jens Axboe
5a2e745d4d io_uring: buffer registration infrastructure
This just prepares the ring for having lists of buffers associated with
it, that the application can provide for SQEs to consume instead of
providing their own.

The buffers are organized by group ID.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-04 11:49:14 -07:00
Pavel Begunkov
e9fd939654 io_uring/io-wq: forward submission ref to async
First it changes io-wq interfaces. It replaces {get,put}_work() with
free_work(), which guaranteed to be called exactly once. It also enforces
free_work() callback to be non-NULL.

io_uring follows the changes and instead of putting a submission reference
in io_put_req_async_completion(), it will be done in io_free_work(). As
removes io_get_work() with corresponding refcount_inc(), the ref balance
is maintained.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-04 11:39:07 -07:00
Pavel Begunkov
7a743e225b io_uring: get next work with submission ref drop
If after dropping the submission reference req->refs == 1, the request
is done, because this one is for io_put_work() and will be dropped
synchronously shortly after. In this case it's safe to steal a next
work from the request.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-03 20:02:49 -07:00
Pavel Begunkov
014db0073c io_uring: remove @nxt from handlers
There will be no use for @nxt in the handlers, and it's doesn't work
anyway, so purge it

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-03 20:02:49 -07:00
Pavel Begunkov
594506fec5 io_uring: make submission ref putting consistent
The rule is simple, any async handler gets a submission ref and should
put it at the end. Make them all follow it, and so more consistent.

This is a preparation patch, and as io_wq_assign_next() currently won't
ever work, this doesn't care to use io_put_req_find_next() instead of
io_put_req().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>

refcount_inc_not_zero() -> refcount_inc() fix.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-03 20:02:35 -07:00
Pavel Begunkov
a2100672f3 io_uring: clean up io_close
Don't abuse labels for plain and straightworward code.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 21:26:56 -07:00
Nathan Chancellor
8755d97a09 io_uring: Ensure mask is initialized in io_arm_poll_handler
Clang warns:

fs/io_uring.c:4178:6: warning: variable 'mask' is used uninitialized
whenever 'if' condition is false [-Wsometimes-uninitialized]
        if (def->pollin)
            ^~~~~~~~~~~
fs/io_uring.c:4182:2: note: uninitialized use occurs here
        mask |= POLLERR | POLLPRI;
        ^~~~
fs/io_uring.c:4178:2: note: remove the 'if' if its condition is always
true
        if (def->pollin)
        ^~~~~~~~~~~~~~~~
fs/io_uring.c:4154:15: note: initialize the variable 'mask' to silence
this warning
        __poll_t mask, ret;
                     ^
                      = 0
1 warning generated.

io_op_defs has many definitions where pollin is not set so mask indeed
might be uninitialized. Initialize it to zero and change the next
assignment to |=, in case further masks are added in the future to avoid
missing changing the assignment then.

Fixes: d7718a9d25 ("io_uring: use poll driven retry for files that support it")
Link: https://github.com/ClangBuiltLinux/linux/issues/916
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 16:13:24 -07:00
Pavel Begunkov
3b17cf5a58 io_uring: remove io_prep_next_work()
io-wq cares about IO_WQ_WORK_UNBOUND flag only while enqueueing, so
it's useless setting it for a next req of a link. Thus, removed it
from io_prep_linked_timeout(), and inline the function.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:06:41 -07:00
Pavel Begunkov
4bc4494ec7 io_uring: remove extra nxt check after punt
After __io_queue_sqe() ended up in io_queue_async_work(), it's already
known that there is no @nxt req, so skip the check and return from the
function.

Also, @nxt initialisation now can be done just before
io_put_req_find_next(), as there is no jumping until it's checked.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:06:40 -07:00
Jens Axboe
d7718a9d25 io_uring: use poll driven retry for files that support it
Currently io_uring tries any request in a non-blocking manner, if it can,
and then retries from a worker thread if we get -EAGAIN. Now that we have
a new and fancy poll based retry backend, use that to retry requests if
the file supports it.

This means that, for example, an IORING_OP_RECVMSG on a socket no longer
requires an async thread to complete the IO. If we get -EAGAIN reading
from the socket in a non-blocking manner, we arm a poll handler for
notification on when the socket becomes readable. When it does, the
pending read is executed directly by the task again, through the io_uring
task work handlers. Not only is this faster and more efficient, it also
means we're not generating potentially tons of async threads that just
sit and block, waiting for the IO to complete.

The feature is marked with IORING_FEAT_FAST_POLL, meaning that async
pollable IO is fast, and that poll<link>other_op is fast as well.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:06:38 -07:00
Jens Axboe
8a72758c51 io_uring: mark requests that we can do poll async in io_op_defs
Add a pollin/pollout field to the request table, and have commands that
we can safely poll for properly marked.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:06:37 -07:00
Jens Axboe
b41e98524e io_uring: add per-task callback handler
For poll requests, it's not uncommon to link a read (or write) after
the poll to execute immediately after the file is marked as ready.
Since the poll completion is called inside the waitqueue wake up handler,
we have to punt that linked request to async context. This slows down
the processing, and actually means it's faster to not use a link for this
use case.

We also run into problems if the completion_lock is contended, as we're
doing a different lock ordering than the issue side is. Hence we have
to do trylock for completion, and if that fails, go async. Poll removal
needs to go async as well, for the same reason.

eventfd notification needs special case as well, to avoid stack blowing
recursion or deadlocks.

These are all deficiencies that were inherited from the aio poll
implementation, but I think we can do better. When a poll completes,
simply queue it up in the task poll list. When the task completes the
list, we can run dependent links inline as well. This means we never
have to go async, and we can remove a bunch of code associated with
that, and optimizations to try and make that run faster. The diffstat
speaks for itself.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02 14:06:36 -07:00
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