1643 Commits

Author SHA1 Message Date
Pavel Begunkov
51ebf1b6a0 io_uring: avoid io-wq -EAGAIN looping for !IOPOLL
[ Upstream commit e0deb6a025ae8c850dc8685be39fb27b06c88736 ]

If an opcode handler semi-reliably returns -EAGAIN, io_wq_submit_work()
might continue busily hammer the same handler over and over again, which
is not ideal. The -EAGAIN handling in question was put there only for
IOPOLL, so restrict it to IOPOLL mode only where there is no other
recourse than to retry as we cannot wait.

Fixes: def596e9557c9 ("io_uring: support for IO polling")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f168b4f24181942f3614dd8ff648221736f572e6.1652433740.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-12 16:35:08 +02:00
Jens Axboe
df1ec53252 io_uring: ensure that fsnotify is always called
[ Upstream commit f63cf5192fe3418ad5ae1a4412eba5694b145f79 ]

Ensure that we call fsnotify_modify() if we write a file, and that we
do fsnotify_access() if we read it. This enables anyone using inotify
on the file to get notified.

Ditto for fallocate, ensure that fsnotify_modify() is called.

Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-12 16:34:57 +02:00
Jens Axboe
50fefe57f4 io_uring: ensure that send/sendmsg and recv/recvmsg check sqe->ioprio
commit 73911426aaaadbae54fa72359b33a7b6a56947db upstream.

All other opcodes correctly check if this is set and -EINVAL if it is
and they don't support that field, for some reason the these were
forgotten.

This was unified a bit differently in the upstream tree, but had the
same effect as making sure we error on this field. Rather than have
a painful backport of the upstream commit, just fixup the mentioned
opcodes.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-07 17:53:28 +02:00
Pavel Begunkov
ea512d540a io_uring: fix not locked access to fixed buf table
commit 05b538c1765f8d14a71ccf5f85258dcbeaf189f7 upstream.

We can look inside the fixed buffer table only while holding
->uring_lock, however in some cases we don't do the right async prep for
IORING_OP_{WRITE,READ}_FIXED ending up with NULL req->imu forcing making
an io-wq worker to try to resolve the fixed buffer without proper
locking.

Move req->imu setup into early req init paths, i.e. io_prep_rw(), which
is called unconditionally for rw requests and under uring_lock.

Fixes: 634d00df5e1cf ("io_uring: add full-fledged dynamic buffers support")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-02 16:41:18 +02:00
Pavel Begunkov
91f5a60a83 io_uring: fix races with buffer table unregister
[ Upstream commit d11d31fc5d8a96f707facee0babdcffaafa38de2 ]

Fixed buffer table quiesce might unlock ->uring_lock, potentially
letting new requests to be submitted, don't allow those requests to
use the table as they will race with unregistration.

Reported-and-tested-by: van fantasy <g1042620637@gmail.com>
Fixes: bd54b6fe3316ec ("io_uring: implement fixed buffers registration similar to fixed files")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-22 14:22:00 +02:00
Pavel Begunkov
b1e7cade3c io_uring: fix races with file table unregister
[ Upstream commit b0380bf6dad4601d92025841e2b7a135d566c6e3 ]

Fixed file table quiesce might unlock ->uring_lock, potentially letting
new requests to be submitted, don't allow those requests to use the
table as they will race with unregistration.

Reported-and-tested-by: van fantasy <g1042620637@gmail.com>
Fixes: 05f3fb3c53975 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-22 14:22:00 +02:00
Pavel Begunkov
5655455a06 io_uring: arm poll for non-nowait files
commit e74ead135bc4459f7d40b1f8edab1333a28b54e8 upstream.

Don't check if we can do nowait before arming apoll, there are several
reasons for that. First, we don't care much about files that don't
support nowait. Second, it may be useful -- we don't want to be taking
away extra workers from io-wq when it can go in some async. Even if it
will go through io-wq eventually, it make difference in the numbers of
workers actually used. And the last one, it's needed to clean nowait in
future commits.

[kernel test robot: fix unused-var]

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9d06f3cb2c8b686d970269a87986f154edb83043.1634425438.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-25 09:57:21 +02:00
Jens Axboe
37811e46a2 io_uring: check reserved fields for recv/recvmsg
[ Upstream commit 5a1e99b61b0c81388cde0c808b3e4173907df19f ]

We should check unused fields for non-zero and -EINVAL if they are set,
making it consistent with other opcodes.

Fixes: aa1fa28fc73e ("io_uring: add support for recvmsg()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-05-09 09:14:38 +02:00
Jens Axboe
79c10cb188 io_uring: check reserved fields for send/sendmsg
[ Upstream commit 588faa1ea5eecb351100ee5d187b9be99210f70d ]

We should check unused fields for non-zero and -EINVAL if they are set,
making it consistent with other opcodes.

Fixes: 0fa03c624d8f ("io_uring: add support for sendmsg()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-05-09 09:14:38 +02:00
Pavel Begunkov
b8ed0f7531 io_uring: use nospec annotation for more indexes
[ Upstream commit 4cdd158be9d09223737df83136a1fb65269d809a ]

There are still several places that using pre array_index_nospec()
indexes, fix them up.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b01ef5ee83f72ed35ad525912370b729f5d145f4.1649336342.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20 09:34:17 +02:00
Pavel Begunkov
5218d5cc02 io_uring: zero tag on rsrc removal
[ Upstream commit 8f0a24801bb44aa58496945aabb904c729176772 ]

Automatically default rsrc tag in io_queue_rsrc_removal(), it's safer
than leaving it there and relying on the rest of the code to behave and
not use it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1cf262a50df17478ea25b22494dcc19f3a80301f.1649336342.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20 09:34:17 +02:00
Dylan Yudaken
9947548d9c io_uring: verify pad field is 0 in io_get_ext_arg
[ Upstream commit d2347b9695dafe5c388a5f9aeb70e27a7a4d29cf ]

Ensure that only 0 is passed for pad here.

Fixes: c73ebb685fb6 ("io_uring: add timeout support for io_uring_enter()")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220412163042.2788062-5-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20 09:34:12 +02:00
Dylan Yudaken
7a7c9f9de9 io_uring: verify that resv2 is 0 in io_uring_rsrc_update2
[ Upstream commit d8a3ba9c143bf89c032deced8a686ffa53b46098 ]

Verify that the user does not pass in anything but 0 for this field.

Fixes: 992da01aa932 ("io_uring: change registration/upd/rsrc tagging ABI")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220412163042.2788062-3-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20 09:34:12 +02:00
Dylan Yudaken
22aa1597f4 io_uring: move io_uring_rsrc_update2 validation
[ Upstream commit 565c5e616e8061b40a2e1d786c418a7ac3503a8d ]

Move validation to be more consistently straight after
copy_from_user. This is already done in io_register_rsrc_update and so
this removes that redundant check.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220412163042.2788062-2-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20 09:34:12 +02:00
Jens Axboe
ba7261af2b io_uring: fix race between timeout flush and removal
commit e677edbcabee849bfdd43f1602bccbecf736a646 upstream.

io_flush_timeouts() assumes the timeout isn't in progress of triggering
or being removed/canceled, so it unconditionally removes it from the
timeout list and attempts to cancel it.

Leave it on the list and let the normal timeout cancelation take care
of it.

Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-13 20:59:22 +02:00
Eugene Syromiatnikov
fe223dd2f1 io_uring: implement compat handling for IORING_REGISTER_IOWQ_AFF
commit 0f5e4b83b37a96e3643951588ed7176b9b187c0a upstream.

Similarly to the way it is done im mbind syscall.

Cc: stable@vger.kernel.org # 5.14
Fixes: fe76421d1da1dcdb ("io_uring: allow user configurable IO thread CPU affinity")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-13 20:59:22 +02:00
Jens Axboe
ae6cba337c io_uring: defer splice/tee file validity check until command issue
commit a3e4bc23d5470b2beb7cc42a86b6a3e75b704c15 upstream.

In preparation for not using the file at prep time, defer checking if this
file refers to a valid io_uring instance until issue time.

This also means we can get rid of the cleanup flag for splice and tee.

Cc: stable@vger.kernel.org # v5.15+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-13 20:59:22 +02:00
Jens Axboe
056e1e7c17 io_uring: don't check req->file in io_fsync_prep()
commit ec858afda857e361182ceafc3d2ba2b164b8e889 upstream.

This is a leftover from the really old days where we weren't able to
track and error early if we need a file and it wasn't assigned. Kill
the check.

Cc: stable@vger.kernel.org # v5.15+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-13 20:59:22 +02:00
Pavel Begunkov
285f5d7240 io_uring: don't touch scm_fp_list after queueing skb
[ Upstream commit a07211e3001435fe8591b992464cd8d5e3c98c5a ]

It's safer to not touch scm_fp_list after we queued an skb to which it
was assigned, there might be races lurking if we screw subtle sync
guarantees on the io_uring side.

Fixes: 6b06314c47e14 ("io_uring: add file set registration")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-13 20:59:20 +02:00
Pavel Begunkov
50c981bd77 io_uring: nospec index for tags on files update
[ Upstream commit 34bb77184123ae401100a4d156584f12fa630e5c ]

Don't forget to array_index_nospec() for indexes before updating rsrc
tags in __io_sqe_files_update(), just use already safe and precalculated
index @i.

Fixes: c3bdad0271834 ("io_uring: add generic rsrc update with tags")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-13 20:59:20 +02:00
Pavel Begunkov
0853bd6885 io_uring: fix memory leak of uid in files registration
commit c86d18f4aa93e0e66cda0e55827cd03eea6bc5f8 upstream.

When there are no files for __io_sqe_files_scm() to process in the
range, it'll free everything and return. However, it forgets to put uid.

Fixes: 08a451739a9b5 ("io_uring: allow sparse fixed file sets")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/accee442376f33ce8aaebb099d04967533efde92.1648226048.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-08 14:24:12 +02:00
Jens Axboe
109dda4510 io_uring: terminate manual loop iterator loop correctly for non-vecs
[ Upstream commit 5e929367468c8f97cd1ffb0417316cecfebef94b ]

The fix for not advancing the iterator if we're using fixed buffers is
broken in that it can hit a condition where we don't terminate the loop.
This results in io-wq looping forever, asking to read (or write) 0 bytes
for every subsequent loop.

Reported-by: Joel Jaeschke <joel.jaeschke@gmail.com>
Link: https://github.com/axboe/liburing/issues/549
Fixes: 16c8d2df7ec0 ("io_uring: ensure symmetry in handling iter types in loop_rw_iter()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08 14:23:10 +02:00
Jens Axboe
1323976e94 io_uring: don't check unrelated req->open.how in accept request
[ Upstream commit adf3a9e9f556613197583a1884f0de40a8bb6fb9 ]

Looks like a victim of too much copy/paste, we should not be looking
at req->open.how in accept. The point is to check CLOEXEC and error
out, which we don't invalid direct descriptors on exec. Hence any
attempt to get a direct descriptor with CLOEXEC is invalid.

No harm is done here, as req->open.how.flags overlaps with
req->accept.flags, but it's very confusing and might change if either of
those command structs are modified.

Fixes: aaa4db12ef7b ("io_uring: accept directly into fixed file table")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08 14:23:10 +02:00
Hao Xu
1bd12b7aae io_uring: fix no lock protection for ctx->cq_extra
[ Upstream commit e302f1046f4c209291b07ff7bc4d15ca26891f16 ]

ctx->cq_extra should be protected by completion lock so that the
req_need_defer() does the right check.

Cc: stable@vger.kernel.org
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211125092103.224502-2-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-03-08 19:12:33 +01:00
Eric Dumazet
c718ea4e73 io_uring: add a schedule point in io_add_buffers()
commit f240762f88b4b1b58561939ffd44837759756477 upstream.

Looping ~65535 times doing kmalloc() calls can trigger soft lockups,
especially with DEBUG features (like KASAN).

[  253.536212] watchdog: BUG: soft lockup - CPU#64 stuck for 26s! [b219417889:12575]
[  253.544433] Modules linked in: vfat fat i2c_mux_pca954x i2c_mux spidev cdc_acm xhci_pci xhci_hcd sha3_generic gq(O)
[  253.544451] CPU: 64 PID: 12575 Comm: b219417889 Tainted: G S         O      5.17.0-smp-DEV #801
[  253.544457] RIP: 0010:kernel_text_address (./include/asm-generic/sections.h:192 ./include/linux/kallsyms.h:29 kernel/extable.c:67 kernel/extable.c:98)
[  253.544464] Code: 0f 93 c0 48 c7 c1 e0 63 d7 a4 48 39 cb 0f 92 c1 20 c1 0f b6 c1 5b 5d c3 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 53 48 89 fb <48> c7 c0 00 00 80 a0 41 be 01 00 00 00 48 39 c7 72 0c 48 c7 c0 40
[  253.544468] RSP: 0018:ffff8882d8baf4c0 EFLAGS: 00000246
[  253.544471] RAX: 1ffff1105b175e00 RBX: ffffffffa13ef09a RCX: 00000000a13ef001
[  253.544474] RDX: ffffffffa13ef09a RSI: ffff8882d8baf558 RDI: ffffffffa13ef09a
[  253.544476] RBP: ffff8882d8baf4d8 R08: ffff8882d8baf5e0 R09: 0000000000000004
[  253.544479] R10: ffff8882d8baf5e8 R11: ffffffffa0d59a50 R12: ffff8882eab20380
[  253.544481] R13: ffffffffa0d59a50 R14: dffffc0000000000 R15: 1ffff1105b175eb0
[  253.544483] FS:  00000000016d3380(0000) GS:ffff88af48c00000(0000) knlGS:0000000000000000
[  253.544486] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  253.544488] CR2: 00000000004af0f0 CR3: 00000002eabfa004 CR4: 00000000003706e0
[  253.544491] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  253.544492] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  253.544494] Call Trace:
[  253.544496]  <TASK>
[  253.544498] ? io_queue_sqe (fs/io_uring.c:7143)
[  253.544505] __kernel_text_address (kernel/extable.c:78)
[  253.544508] unwind_get_return_address (arch/x86/kernel/unwind_frame.c:19)
[  253.544514] arch_stack_walk (arch/x86/kernel/stacktrace.c:27)
[  253.544517] ? io_queue_sqe (fs/io_uring.c:7143)
[  253.544521] stack_trace_save (kernel/stacktrace.c:123)
[  253.544527] ____kasan_kmalloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:515)
[  253.544531] ? ____kasan_kmalloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:515)
[  253.544533] ? __kasan_kmalloc (mm/kasan/common.c:524)
[  253.544535] ? kmem_cache_alloc_trace (./include/linux/kasan.h:270 mm/slab.c:3567)
[  253.544541] ? io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828)
[  253.544544] ? __io_queue_sqe (fs/io_uring.c:?)
[  253.544551] __kasan_kmalloc (mm/kasan/common.c:524)
[  253.544553] kmem_cache_alloc_trace (./include/linux/kasan.h:270 mm/slab.c:3567)
[  253.544556] ? io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828)
[  253.544560] io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828)
[  253.544564] ? __kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469)
[  253.544567] ? __kasan_slab_alloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469)
[  253.544569] ? kmem_cache_alloc_bulk (mm/slab.h:732 mm/slab.c:3546)
[  253.544573] ? __io_alloc_req_refill (fs/io_uring.c:2078)
[  253.544578] ? io_submit_sqes (fs/io_uring.c:7441)
[  253.544581] ? __se_sys_io_uring_enter (fs/io_uring.c:10154 fs/io_uring.c:10096)
[  253.544584] ? __x64_sys_io_uring_enter (fs/io_uring.c:10096)
[  253.544587] ? do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
[  253.544590] ? entry_SYSCALL_64_after_hwframe (??:?)
[  253.544596] __io_queue_sqe (fs/io_uring.c:?)
[  253.544600] io_queue_sqe (fs/io_uring.c:7143)
[  253.544603] io_submit_sqe (fs/io_uring.c:?)
[  253.544608] io_submit_sqes (fs/io_uring.c:?)
[  253.544612] __se_sys_io_uring_enter (fs/io_uring.c:10154 fs/io_uring.c:10096)
[  253.544616] __x64_sys_io_uring_enter (fs/io_uring.c:10096)
[  253.544619] do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
[  253.544623] entry_SYSCALL_64_after_hwframe (??:?)

Fixes: ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: io-uring <io-uring@vger.kernel.org>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20220215041003.2394784-1-eric.dumazet@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-02 11:47:56 +01:00
Dylan Yudaken
0d773aaf5a io_uring: disallow modification of rsrc_data during quiesce
commit 80912cef18f16f8fe59d1fb9548d4364342be360 upstream.

io_rsrc_ref_quiesce will unlock the uring while it waits for references to
the io_rsrc_data to be killed.
There are other places to the data that might add references to data via
calls to io_rsrc_node_switch.
There is a race condition where this reference can be added after the
completion has been signalled. At this point the io_rsrc_ref_quiesce call
will wake up and relock the uring, assuming the data is unused and can be
freed - although it is actually being used.

To fix this check in io_rsrc_ref_quiesce if a resource has been revived.

Reported-by: syzbot+ca8bf833622a1662745b@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220222161751.995746-1-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-02 11:47:48 +01:00
Jens Axboe
7c83437fb3 io_uring: don't convert to jiffies for waiting on timeouts
commit 228339662b398a59b3560cd571deb8b25b253c7e upstream.

If an application calls io_uring_enter(2) with a timespec passed in,
convert that timespec to ktime_t rather than jiffies. The latter does
not provide the granularity the application may expect, and may in
fact provided different granularity on different systems, depending
on what the HZ value is configured at.

Turn the timespec into an absolute ktime_t, and use that with
schedule_hrtimeout() instead.

Link: https://github.com/axboe/liburing/issues/531
Cc: stable@vger.kernel.org
Reported-by: Bob Chen <chenbo.chen@alibaba-inc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-02 11:47:48 +01:00
Shakeel Butt
246dfbc125 mm: io_uring: allow oom-killer from io_uring_setup
[ Upstream commit 0a3f1e0beacf6cc8ae5f846b0641c1df476e83d6 ]

On an overcommitted system which is running multiple workloads of
varying priorities, it is preferred to trigger an oom-killer to kill a
low priority workload than to let the high priority workload receiving
ENOMEMs. On our memory overcommitted systems, we are seeing a lot of
ENOMEMs instead of oom-kills because io_uring_setup callchain is using
__GFP_NORETRY gfp flag which avoids the oom-killer. Let's remove it and
allow the oom-killer to kill a lower priority job.

Signed-off-by: Shakeel Butt <shakeelb@google.com>
Link: https://lore.kernel.org/r/20220125051736.2981459-1-shakeelb@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-23 12:03:18 +01:00
Dylan Yudaken
82cc3382e3 io_uring: fix bug in slow unregistering of nodes
[ Upstream commit b36a2050040b2d839bdc044007cdd57101d7f881 ]

In some cases io_rsrc_ref_quiesce will call io_rsrc_node_switch_start,
and then immediately flush the delayed work queue &ctx->rsrc_put_work.

However the percpu_ref_put does not immediately destroy the node, it
will be called asynchronously via RCU. That ends up with
io_rsrc_node_ref_zero only being called after rsrc_put_work has been
flushed, and so the process ends up sleeping for 1 second unnecessarily.

This patch executes the put code immediately if we are busy
quiescing.

Fixes: 4a38aed2a0a7 ("io_uring: batch reap of dead file registrations")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220121123856.3557884-1-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-01 17:27:11 +01:00
Pavel Begunkov
b168b1a039 io_uring: fix not released cached task refs
commit 3cc7fdb9f90a25ae92250bf9e6cf3b9556b230e9 upstream.

tctx_task_work() may get run after io_uring cancellation and so there
will be no one to put cached in tctx task refs that may have been added
back by tw handlers using inline completion infra, Call
io_uring_drop_tctx_refs() at the end of the main tw handler to release
them.

Cc: stable@vger.kernel.org # 5.15+
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Fixes: e98e49b2bbf7 ("io_uring: extend task put optimisations")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/69f226b35fbdb996ab799a8bbc1c06bf634ccec1.1641688805.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-29 10:58:24 +01:00
Pavel Begunkov
deb0c71e0b io_uring: remove double poll on poll update
[ Upstream commit e840b4baf3cfb37e2ead4f649a45bb78178677ff ]

Before updating a poll request we should remove it from poll queues,
including the double poll entry.

Fixes: b69de288e913 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ac39e7f80152613603b8a6cc29a2b6063ac2434f.1639605189.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-01-27 11:03:48 +01:00
Jens Axboe
20fb0dc35b io_uring: zero iocb->ki_pos for stream file types
[ Upstream commit 7b9762a5e8837b92a027d58d396a9d27f6440c36 ]

io_uring supports using offset == -1 for using the current file position,
and we read that in as part of read/write command setup. For the non-iter
read/write types we pass in NULL for the position pointer, but for the
iter types we should not be passing any anything but 0 for the position
for a stream.

Clear kiocb->ki_pos if the file is a stream, don't leave it as -1. If we
do, then the request will error with -ESPIPE.

Fixes: ba04291eb66e ("io_uring: allow use of offset == -1 to mean file position")
Link: https://github.com/axboe/liburing/discussions/501
Reported-by: Samuel Williams <samuel.williams@oriontransfer.co.nz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-12-29 12:28:45 +01:00
Jens Axboe
8e12976c0c io_uring: ensure task_work gets run as part of cancelations
commit 78a780602075d8b00c98070fa26e389b3b3efa72 upstream.

If we successfully cancel a work item but that work item needs to be
processed through task_work, then we can be sleeping uninterruptibly
in io_uring_cancel_generic() and never process it. Hence we don't
make forward progress and we end up with an uninterruptible sleep
warning.

While in there, correct a comment that should be IFF, not IIF.

Reported-and-tested-by: syzbot+21e6887c0be14181206d@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-14 10:57:15 +01:00
Ye Bin
2d447d318b io_uring: fix soft lockup when call __io_remove_buffers
commit 1d0254e6b47e73222fd3d6ae95cccbaafe5b3ecf upstream.

I got issue as follows:
[ 567.094140] __io_remove_buffers: [1]start ctx=0xffff8881067bf000 bgid=65533 buf=0xffff8881fefe1680
[  594.360799] watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [kworker/u32:5:108]
[  594.364987] Modules linked in:
[  594.365405] irq event stamp: 604180238
[  594.365906] hardirqs last  enabled at (604180237): [<ffffffff93fec9bd>] _raw_spin_unlock_irqrestore+0x2d/0x50
[  594.367181] hardirqs last disabled at (604180238): [<ffffffff93fbbadb>] sysvec_apic_timer_interrupt+0xb/0xc0
[  594.368420] softirqs last  enabled at (569080666): [<ffffffff94200654>] __do_softirq+0x654/0xa9e
[  594.369551] softirqs last disabled at (569080575): [<ffffffff913e1d6a>] irq_exit_rcu+0x1ca/0x250
[  594.370692] CPU: 2 PID: 108 Comm: kworker/u32:5 Tainted: G            L    5.15.0-next-20211112+ #88
[  594.371891] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
[  594.373604] Workqueue: events_unbound io_ring_exit_work
[  594.374303] RIP: 0010:_raw_spin_unlock_irqrestore+0x33/0x50
[  594.375037] Code: 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 55 f5 55 fd 48 89 ef e8 ed a7 56 fd 80 e7 02 74 06 e8 43 13 7b fd fb bf 01 00 00 00 <e8> f8 78 474
[  594.377433] RSP: 0018:ffff888101587a70 EFLAGS: 00000202
[  594.378120] RAX: 0000000024030f0d RBX: 0000000000000246 RCX: 1ffffffff2f09106
[  594.379053] RDX: 0000000000000000 RSI: ffffffff9449f0e0 RDI: 0000000000000001
[  594.379991] RBP: ffffffff9586cdc0 R08: 0000000000000001 R09: fffffbfff2effcab
[  594.380923] R10: ffffffff977fe557 R11: fffffbfff2effcaa R12: ffff8881b8f3def0
[  594.381858] R13: 0000000000000246 R14: ffff888153a8b070 R15: 0000000000000000
[  594.382787] FS:  0000000000000000(0000) GS:ffff888399c00000(0000) knlGS:0000000000000000
[  594.383851] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  594.384602] CR2: 00007fcbe71d2000 CR3: 00000000b4216000 CR4: 00000000000006e0
[  594.385540] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  594.386474] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  594.387403] Call Trace:
[  594.387738]  <TASK>
[  594.388042]  find_and_remove_object+0x118/0x160
[  594.389321]  delete_object_full+0xc/0x20
[  594.389852]  kfree+0x193/0x470
[  594.390275]  __io_remove_buffers.part.0+0xed/0x147
[  594.390931]  io_ring_ctx_free+0x342/0x6a2
[  594.392159]  io_ring_exit_work+0x41e/0x486
[  594.396419]  process_one_work+0x906/0x15a0
[  594.399185]  worker_thread+0x8b/0xd80
[  594.400259]  kthread+0x3bf/0x4a0
[  594.401847]  ret_from_fork+0x22/0x30
[  594.402343]  </TASK>

Message from syslogd@localhost at Nov 13 09:09:54 ...
kernel:watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [kworker/u32:5:108]
[  596.793660] __io_remove_buffers: [2099199]start ctx=0xffff8881067bf000 bgid=65533 buf=0xffff8881fefe1680

We can reproduce this issue by follow syzkaller log:
r0 = syz_io_uring_setup(0x401, &(0x7f0000000300), &(0x7f0000003000/0x2000)=nil, &(0x7f0000ff8000/0x4000)=nil, &(0x7f0000000280)=<r1=>0x0, &(0x7f0000000380)=<r2=>0x0)
sendmsg$ETHTOOL_MSG_FEATURES_SET(0xffffffffffffffff, &(0x7f0000003080)={0x0, 0x0, &(0x7f0000003040)={&(0x7f0000000040)=ANY=[], 0x18}}, 0x0)
syz_io_uring_submit(r1, r2, &(0x7f0000000240)=@IORING_OP_PROVIDE_BUFFERS={0x1f, 0x5, 0x0, 0x401, 0x1, 0x0, 0x100, 0x0, 0x1, {0xfffd}}, 0x0)
io_uring_enter(r0, 0x3a2d, 0x0, 0x0, 0x0, 0x0)

The reason above issue  is 'buf->list' has 2,100,000 nodes, occupied cpu lead
to soft lockup.
To solve this issue, we need add schedule point when do while loop in
'__io_remove_buffers'.
After add  schedule point we do regression, get follow data.
[  240.141864] __io_remove_buffers: [1]start ctx=0xffff888170603000 bgid=65533 buf=0xffff8881116fcb00
[  268.408260] __io_remove_buffers: [1]start ctx=0xffff8881b92d2000 bgid=65533 buf=0xffff888130c83180
[  275.899234] __io_remove_buffers: [2099199]start ctx=0xffff888170603000 bgid=65533 buf=0xffff8881116fcb00
[  296.741404] __io_remove_buffers: [1]start ctx=0xffff8881b659c000 bgid=65533 buf=0xffff8881010fe380
[  305.090059] __io_remove_buffers: [2099199]start ctx=0xffff8881b92d2000 bgid=65533 buf=0xffff888130c83180
[  325.415746] __io_remove_buffers: [1]start ctx=0xffff8881b92d1000 bgid=65533 buf=0xffff8881a17d8f00
[  333.160318] __io_remove_buffers: [2099199]start ctx=0xffff8881b659c000 bgid=65533 buf=0xffff8881010fe380
...

Fixes:8bab4c09f24e("io_uring: allow conditional reschedule for intensive iterators")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20211122024737.2198530-1-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-01 09:04:56 +01:00
Pavel Begunkov
1c939a53b2 io_uring: fix link traversal locking
commit 6af3f48bf6156a7f02e91aca64e2927c4bebda03 upstream.

WARNING: inconsistent lock state
5.16.0-rc2-syzkaller #0 Not tainted
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
ffff888078e11418 (&ctx->timeout_lock
){?.+.}-{2:2}
, at: io_timeout_fn+0x6f/0x360 fs/io_uring.c:5943
{HARDIRQ-ON-W} state was registered at:
  [...]
  spin_unlock_irq include/linux/spinlock.h:399 [inline]
  __io_poll_remove_one fs/io_uring.c:5669 [inline]
  __io_poll_remove_one fs/io_uring.c:5654 [inline]
  io_poll_remove_one+0x236/0x870 fs/io_uring.c:5680
  io_poll_remove_all+0x1af/0x235 fs/io_uring.c:5709
  io_ring_ctx_wait_and_kill+0x1cc/0x322 fs/io_uring.c:9534
  io_uring_release+0x42/0x46 fs/io_uring.c:9554
  __fput+0x286/0x9f0 fs/file_table.c:280
  task_work_run+0xdd/0x1a0 kernel/task_work.c:164
  exit_task_work include/linux/task_work.h:32 [inline]
  do_exit+0xc14/0x2b40 kernel/exit.c:832

674ee8e1b4a41 ("io_uring: correct link-list traversal locking") fixed a
data race but introduced a possible deadlock and inconsistentcy in irq
states. E.g.

io_poll_remove_all()
    spin_lock_irq(timeout_lock)
    io_poll_remove_one()
        spin_lock/unlock_irq(poll_lock);
    spin_unlock_irq(timeout_lock)

Another type of problem is freeing a request while holding
->timeout_lock, which may leads to a deadlock in
io_commit_cqring() -> io_flush_timeouts() and other places.

Having 3 nested locks is also too ugly. Add io_match_task_safe(), which
would briefly take and release timeout_lock for race prevention inside,
so the actuall request cancellation / free / etc. code doesn't have it
taken.

Reported-by: syzbot+ff49a3059d49b0ca0eec@syzkaller.appspotmail.com
Reported-by: syzbot+847f02ec20a6609a328b@syzkaller.appspotmail.com
Reported-by: syzbot+3368aadcd30425ceb53b@syzkaller.appspotmail.com
Reported-by: syzbot+51ce8887cdef77c9ac83@syzkaller.appspotmail.com
Reported-by: syzbot+3cb756a49d2f394a9ee3@syzkaller.appspotmail.com
Fixes: 674ee8e1b4a41 ("io_uring: correct link-list traversal locking")
Cc: stable@kernel.org # 5.15+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/397f7ebf3f4171f1abe41f708ac1ecb5766f0b68.1637937097.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-01 09:04:42 +01:00
Pavel Begunkov
3d2a1e68fd io_uring: fail cancellation for EXITING tasks
commit 617a89484debcd4e7999796d693cf0b77d2519de upstream.

WARNING: CPU: 1 PID: 20 at fs/io_uring.c:6269 io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269
CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.16.0-rc1-syzkaller #0
Workqueue: events io_fallback_req_func
RIP: 0010:io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269
Call Trace:
 <TASK>
 io_req_task_link_timeout+0x6b/0x1e0 fs/io_uring.c:6886
 io_fallback_req_func+0xf9/0x1ae fs/io_uring.c:1334
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

We need original task's context to do cancellations, so if it's dying
and the callback is executed in a fallback mode, fail the cancellation
attempt.

Fixes: 89b263f6d56e6 ("io_uring: run linked timeouts from task_work")
Cc: stable@kernel.org # 5.15+
Reported-by: syzbot+ab0cfe96c2b3cd1c1153@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4c41c5f379c6941ad5a07cd48cb66ed62199cf7e.1637937097.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-01 09:04:42 +01:00
Pavel Begunkov
09eb40f677 io_uring: correct link-list traversal locking
commit 674ee8e1b4a41d2fdffc885c55350c3fbb38c22a upstream.

As io_remove_next_linked() is now under ->timeout_lock (see
io_link_timeout_fn), we should update locking around io_for_each_link()
and io_match_task() to use the new lock.

Cc: stable@kernel.org # 5.15+
Fixes: 89850fce16a1a ("io_uring: run timeouts from task_work")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b54541cedf7de59cb5ae36109e58529ca16e66aa.1637631883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-01 09:04:42 +01:00
Pavel Begunkov
4cac487a47 io_uring: honour zeroes as io-wq worker limits
commit bad119b9a00019054f0c9e2045f312ed63ace4f4 upstream.

When we pass in zero as an io-wq worker number limit it shouldn't
actually change the limits but return the old value, follow that
behaviour with deferred limits setup as well.

Cc: stable@kernel.org # 5.15
Reported-by: Beld Zhang <beldzhang@gmail.com>
Fixes: e139a1ec92f8d ("io_uring: apply max_workers limit to all future users")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1b222a92f7a78a24b042763805e891a4cdd4b544.1636384034.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-18 19:16:03 +01:00
Pavel Begunkov
b22fa62a35 io_uring: apply worker limits to previous users
Another change to the API io-wq worker limitation API added in 5.15,
apply the limit to all prior users that already registered a tctx. It
may be confusing as it's now, in particular the change covers the
following 2 cases:

TASK1                   | TASK2
_________________________________________________
ring = create()         |
                        | limit_iowq_workers()
*not limited*           |

TASK1                   | TASK2
_________________________________________________
ring = create()         |
                        | issue_requests()
limit_iowq_workers()    |
                        | *not limited*

A note on locking, it's safe to traverse ->tctx_list as we hold
->uring_lock, but do that after dropping sqd->lock to avoid possible
problems. It's also safe to access tctx->io_wq there because tasks
kill it only after removing themselves from tctx_list, see
io_uring_cancel_generic() -> io_uring_clean_tctx()

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d6e09ecc3545e4dc56e43c906ee3d71b7ae21bed.1634818641.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21 11:19:38 -06:00
Pavel Begunkov
4ea672ab69 io_uring: fix ltimeout unprep
io_unprep_linked_timeout() is broken, first it needs to return back
REQ_F_ARM_LTIMEOUT, so the linked timeout is enqueued and disarmed. But
now we refcounted it, and linked timeouts may get not executed at all,
leaking a request.

Just kill the unprep optimisation.

Fixes: 906c6caaf586 ("io_uring: optimise io_prep_linked_timeout()")
Reported-by: Beld Zhang <beldzhang@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/51b8e2bfc4bea8ee625cf2ba62b2a350cc9be031.1634719585.git.asml.silence@gmail.com
Link: https://github.com/axboe/liburing/issues/460
Reported-by: Beld Zhang <beldzhang@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 09:54:16 -06:00
Pavel Begunkov
e139a1ec92 io_uring: apply max_workers limit to all future users
Currently, IORING_REGISTER_IOWQ_MAX_WORKERS applies only to the task
that issued it, it's unexpected for users. If one task creates a ring,
limits workers and then passes it to another task the limit won't be
applied to the other task.

Another pitfall is that a task should either create a ring or submit at
least one request for IORING_REGISTER_IOWQ_MAX_WORKERS to work at all,
furher complicating the picture.

Change the API, save the limits and apply to all future users. Note, it
should be done first before giving away the ring or submitting new
requests otherwise the result is not guaranteed.

Fixes: 2e480058ddc2 ("io-wq: provide a way to limit max number of workers")
Link: https://github.com/axboe/liburing/issues/460
Reported-by: Beld Zhang <beldzhang@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/51d0bae97180e08ab722c0d5c93e7439cfb6f697.1634683237.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-20 09:54:06 -06:00
Hao Xu
14cfbb7a78 io_uring: fix wrong condition to grab uring lock
Grab uring lock when we are in io-worker rather than in the original
or system-wq context since we already hold it in these two situation.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Fixes: b66ceaf324b3 ("io_uring: move iopoll reissue into regular IO path")
Link: https://lore.kernel.org/r/20211014140400.50235-1-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-14 09:06:11 -06:00
Pavel Begunkov
3f008385d4 io_uring: kill fasync
We have never supported fasync properly, it would only fire when there
is something polling io_uring making it useless. The original support came
in through the initial io_uring merge for 5.1. Since it's broken and
nobody has reported it, get rid of the fasync bits.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/2f7ca3d344d406d34fa6713824198915c41cea86.1633080236.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-01 11:16:02 -06:00
Pavel Begunkov
7df778be2f io_uring: make OP_CLOSE consistent with direct open
From recently open/accept are now able to manipulate fixed file table,
but it's inconsistent that close can't. Close the gap, keep API same as
with open/accept, i.e. via sqe->file_slot.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-24 14:07:54 -06:00
Pavel Begunkov
9f3a2cb228 io_uring: kill extra checks in io_write()
We don't retry short writes and so we would never get to async setup in
io_write() in that case. Thus ret2 > 0 is always false and
iov_iter_advance() is never used. Apparently, the same is found by
Coverity, which complains on the code.

Fixes: cd65869512ab ("io_uring: use iov_iter state save/restore helpers")
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5b33e61034748ef1022766efc0fb8854cfcf749c.1632500058.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-24 10:26:11 -06:00
Jens Axboe
cdb31c29d3 io_uring: don't punt files update to io-wq unconditionally
There's no reason to punt it unconditionally, we just need to ensure that
the submit lock grabbing is conditional.

Fixes: 05f3fb3c5397 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-24 10:24:34 -06:00
Jens Axboe
9990da93d2 io_uring: put provided buffer meta data under memcg accounting
For each provided buffer, we allocate a struct io_buffer to hold the
data associated with it. As a large number of buffers can be provided,
account that data with memcg.

Fixes: ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-24 10:24:34 -06:00
Jens Axboe
8bab4c09f2 io_uring: allow conditional reschedule for intensive iterators
If we have a lot of threads and rings, the tctx list can get quite big.
This is especially true if we keep creating new threads and rings.
Likewise for the provided buffers list. Be nice and insert a conditional
reschedule point while iterating the nodes for deletion.

Link: https://lore.kernel.org/io-uring/00000000000064b6b405ccb41113@google.com/
Reported-by: syzbot+111d2a03f51f5ae73775@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-24 10:24:34 -06:00
Hao Xu
5b7aa38d86 io_uring: fix potential req refcount underflow
For multishot mode, there may be cases like:

iowq                                 original context
io_poll_add
  _arm_poll()
  mask = vfs_poll() is not 0
  if mask
(2)  io_poll_complete()
  compl_unlock
   (interruption happens
    tw queued to original
    context)
                                     io_poll_task_func()
                                     compl_lock
                                 (3) done = io_poll_complete() is true
                                     compl_unlock
                                     put req ref
(1) if (poll->flags & EPOLLONESHOT)
      put req ref

EPOLLONESHOT flag in (1) may be from (2) or (3), so there are multiple
combinations that can cause ref underfow.
Let's address it by:
- check the return value in (2) as done
- change (1) to if (done)
    in this way, we only do ref put in (1) if 'oneshot flag' is from
    (2)
- do poll.done check in io_poll_task_func(), so that we won't put ref
  for the second time.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210922101238.7177-4-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-24 10:24:34 -06:00
Hao Xu
a62682f92e io_uring: fix missing set of EPOLLONESHOT for CQ ring overflow
We should set EPOLLONESHOT if cqring_fill_event() returns false since
io_poll_add() decides to put req or not by it.

Fixes: 5082620fb2ca ("io_uring: terminate multishot poll for CQ ring overflow")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210922101238.7177-3-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-24 10:24:34 -06:00