Commit Graph

69489 Commits

Author SHA1 Message Date
Pavel Begunkov
180f829fe4 io_uring: fix complete_post use ctx after free
If io_req_complete_post() put not a final ref, we can't rely on the
request's ctx ref, and so ctx may potentially be freed while
complete_post() is in io_cqring_ev_posted()/etc.

In that case get an additional ctx reference, and put it in the end, so
protecting following io_cqring_ev_posted(). And also prolong ctx
lifetime until spin_unlock happens, as we do with mutexes, so added
percpu_ref_get() doesn't race with ctx free.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-15 09:32:24 -06:00
Pavel Begunkov
efe814a471 io_uring: fix ->flags races by linked timeouts
It's racy to modify req->flags from a not owning context, e.g. linked
timeout calling req_set_fail_links() for the master request might race
with that request setting/clearing flags while being executed
concurrently. Just remove req_set_fail_links(prev) from
io_link_timeout_fn(), io_async_find_and_cancel() and functions down the
line take care of setting the fail bit.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-15 09:31:19 -06:00
Jens Axboe
9e15c3a0ce io_uring: convert io_buffer_idr to XArray
Like we did for the personality idr, convert the IO buffer idr to use
XArray. This avoids a use-after-free on removal of entries, since idr
doesn't like doing so from inside an iterator, and it nicely reduces
the amount of code we need to support this feature.

Fixes: 5a2e745d4d ("io_uring: buffer registration infrastructure")
Cc: stable@vger.kernel.org
Cc: Matthew Wilcox <willy@infradead.org>
Cc: yangerkun <yangerkun@huawei.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-14 09:56:14 -06:00
Jens Axboe
16efa4fce3 io_uring: allow IO worker threads to be frozen
With the freezer using the proper signaling to notify us of when it's
time to freeze a thread, we can re-enable normal freezer usage for the
IO threads. Ensure that SQPOLL, io-wq, and the io-wq manager call
try_to_freeze() appropriately, and remove the default setting of
PF_NOFREEZE from create_io_thread().

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-12 20:26:13 -07:00
Pavel Begunkov
58f9937383 io_uring: fix OP_ASYNC_CANCEL across tasks
IORING_OP_ASYNC_CANCEL tries io-wq cancellation only for current task.
If it fails go over tctx_list and try it out for every single tctx.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-12 09:42:56 -07:00
Pavel Begunkov
521d6a737a io_uring: cancel sqpoll via task_work
1) The first problem is io_uring_cancel_sqpoll() ->
io_uring_cancel_task_requests() basically doing park(); park(); and so
hanging.

2) Another one is more subtle, when the master task is doing cancellations,
but SQPOLL task submits in-between the end of the cancellation but
before finish() requests taking a ref to the ctx, and so eternally
locking it up.

3) Yet another is a dying SQPOLL task doing io_uring_cancel_sqpoll() and
same io_uring_cancel_sqpoll() from the owner task, they race for
tctx->wait events. And there probably more of them.

Instead do SQPOLL cancellations from within SQPOLL task context via
task_work, see io_sqpoll_cancel_sync(). With that we don't need temporal
park()/unpark() during cancellation, which is ugly, subtle and anyway
doesn't allow to do io_run_task_work() properly.

io_uring_cancel_sqpoll() is called only from SQPOLL task context and
under sqd locking, so all parking is removed from there. And so,
io_sq_thread_[un]park() and io_sq_thread_stop() are not used now by
SQPOLL task, and that spare us from some headache.

Also remove ctx->sqd_list early to avoid 2). And kill tctx->sqpoll,
which is not used anymore.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-12 09:42:55 -07:00
Pavel Begunkov
26984fbf3a io_uring: prevent racy sqd->thread checks
SQPOLL thread to which we're trying to attach may be going away, it's
not nice but a more serious problem is if io_sq_offload_create() sees
sqd->thread==NULL, and tries to init it with a new thread. There are
tons of ways it can be exploited or fail.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-12 09:42:53 -07:00
Pavel Begunkov
0df8ea602b io_uring: remove useless ->startup completion
We always do complete(&sqd->startup) almost right after sqd->thread
creation, either in the success path or in io_sq_thread_finish(). It's
specifically created not started for us to be able to set some stuff
like sqd->thread and io_uring_alloc_task_context() before following
right after wake_up_new_task().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-12 07:23:01 -07:00
Pavel Begunkov
e1915f76a8 io_uring: cancel deferred requests in try_cancel
As io_uring_cancel_files() and others let SQO to run between
io_uring_try_cancel_requests(), SQO may generate new deferred requests,
so it's safer to try to cancel them in it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-12 07:23:00 -07:00
Jens Axboe
d052d1d685 io_uring: perform IOPOLL reaping if canceler is thread itself
We bypass IOPOLL completion polling (and reaping) for the SQPOLL thread,
but if it's the thread itself invoking cancelations, then we still need
to perform it or no one will.

Fixes: 9936c7c2bc ("io_uring: deduplicate core cancellations sequence")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-11 10:49:20 -07:00
Jens Axboe
5c2469e0a2 io_uring: force creation of separate context for ATTACH_WQ and non-threads
Earlier kernels had SQPOLL threads that could share across anything, as
we grabbed the context we needed on a per-ring basis. This is no longer
the case, so only allow attaching directly if we're in the same thread
group. That is the common use case. For non-group tasks, just setup a
new context and thread as we would've done if sharing wasn't set. This
isn't 100% ideal in terms of CPU utilization for the forked and share
case, but hopefully that isn't much of a concern. If it is, there are
plans in motion for how to improve that. Most importantly, we want to
avoid app side regressions where sharing worked before and now doesn't.
With this patch, functionality is equivalent to previous kernels that
supported IORING_SETUP_ATTACH_WQ with SQPOLL.

Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-11 10:17:56 -07:00
Pavel Begunkov
7d41e8543d io_uring: remove indirect ctx into sqo injection
We use ->ctx_new_list to notify sqo about new ctx pending, then sqo
should stop and splice it to its sqd->ctx_list, paired with
->sq_thread_comp.

The last one is broken because nobody reinitialises it, and trying to
fix it would only add more complexity and bugs. And the first isn't
really needed as is done under park(), that protects from races well.
Add ctx into sqd->ctx_list directly (under park()), it's much simpler
and allows to kill both, ctx_new_list and sq_thread_comp.

note: apparently there is no real problem at the moment, because
sq_thread_comp is used only by io_sq_thread_finish() followed by
parking, where list_del(&ctx->sqd_list) removes it well regardless
whether it's in the new or the active list.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:30:32 -07:00
Pavel Begunkov
78d7f6ba82 io_uring: fix invalid ctx->sq_thread_idle
We have to set ctx->sq_thread_idle before adding a ring to an SQ task,
otherwise sqd races for seeing zero and accounting it as such.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:29:59 -07:00
Jens Axboe
e22bc9b481 kernel: make IO threads unfreezable by default
The io-wq threads were already marked as no-freeze, but the manager was
not. On resume, we perpetually have signal_pending() being true, and
hence the manager will loop and spin 100% of the time.

Just mark the tasks created by create_io_thread() as PF_NOFREEZE by
default, and remove any knowledge of it in io-wq and io_uring.

Reported-by: Kevin Locke <kevin@kevinlocke.name>
Tested-by: Kevin Locke <kevin@kevinlocke.name>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:43 -07:00
Jens Axboe
e8f98f2454 io_uring: always wait for sqd exited when stopping SQPOLL thread
We have a tiny race where io_put_sq_data() calls io_sq_thead_stop()
and finds the thread gone, but the thread has indeed not fully
exited or called complete() yet. Close it up by always having
io_sq_thread_stop() wait on completion of the exit event.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:43 -07:00
Yang Li
5199328a0d io_uring: remove unneeded variable 'ret'
Fix the following coccicheck warning:
./fs/io_uring.c:8984:5-8: Unneeded variable: "ret". Return "0" on line
8998

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/1615271441-33649-1-git-send-email-yang.lee@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:43 -07:00
Jens Axboe
93e68e036c io_uring: move all io_kiocb init early in io_init_req()
If we hit an error path in the function, make sure that the io_kiocb is
fully initialized at that point so that freeing the request always sees
a valid state.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:43 -07:00
yangerkun
70e3512509 io-wq: fix ref leak for req in case of exit cancelations
do_work such as io_wq_submit_work that cancel the work may leave a ref of
req as 1 if we have links. Fix it by call io_run_cancel.

Fixes: 4fb6ac3262 ("io-wq: improve manager/worker handling over exec")
Signed-off-by: yangerkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20210309030410.3294078-1-yangerkun@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:42 -07:00
Pavel Begunkov
7a612350a9 io_uring: fix complete_post races for linked req
Calling io_queue_next() after spin_unlock in io_req_complete_post()
races with the other side extracting and reusing this request. Hand
coded parts of io_req_find_next() considering that io_disarm_next()
and io_req_task_queue() have (and safe) to be called with
completion_lock held.

It already does io_commit_cqring() and io_cqring_ev_posted(), so just
reuse it for post io_disarm_next().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5672a62f3150ee7c55849f40c0037655c4f2840f.1615250156.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:42 -07:00
Pavel Begunkov
33cc89a9fc io_uring: add io_disarm_next() helper
A preparation patch placing all preparations before extracting a next
request into a separate helper io_disarm_next().

Also, don't spuriously do ev_posted in a rare case where REQ_F_FAIL_LINK
is set but there are no requests linked (i.e. after cancelling a linked
timeout or setting IOSQE_IO_LINK on a last request of a submission
batch).

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/44ecff68d6b47e1c4e6b891bdde1ddc08cfc3590.1615250156.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:42 -07:00
Pavel Begunkov
97a73a0f9f io_uring: fix io_sq_offload_create error handling
Don't set IO_SQ_THREAD_SHOULD_STOP when io_sq_offload_create() has
failed on io_uring_alloc_task_context() but leave everything to
io_sq_thread_finish(), because currently io_sq_thread_finish()
hangs on trying to park it. That's great it stalls there, because
otherwise the following io_sq_thread_stop() would be skipped on
IO_SQ_THREAD_SHOULD_STOP check and the sqo would race for sqd with
freeing ctx.

A simple error injection gives something like this.

[  245.463955] INFO: task sqpoll-test-hang:523 blocked for more than 122 seconds.
[  245.463983] Call Trace:
[  245.463990]  __schedule+0x36b/0x950
[  245.464005]  schedule+0x68/0xe0
[  245.464013]  schedule_timeout+0x209/0x2a0
[  245.464032]  wait_for_completion+0x8b/0xf0
[  245.464043]  io_sq_thread_finish+0x44/0x1a0
[  245.464049]  io_uring_setup+0x9ea/0xc80
[  245.464058]  __x64_sys_io_uring_setup+0x16/0x20
[  245.464064]  do_syscall_64+0x38/0x50
[  245.464073]  entry_SYSCALL_64_after_hwframe+0x44/0xae

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:42 -07:00
Jens Axboe
cc20e3fec6 io-wq: remove unused 'user' member of io_wq
Previous patches killed the last user of this, now it's just a dead member
in the struct. Get rid of it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:42 -07:00
Matthew Wilcox (Oracle)
61cf93700f io_uring: Convert personality_idr to XArray
You can't call idr_remove() from within a idr_for_each() callback,
but you can call xa_erase() from an xa_for_each() loop, so switch the
entire personality_idr from the IDR to the XArray.  This manifests as a
use-after-free as idr_for_each() attempts to walk the rest of the node
after removing the last entry from it.

Fixes: 071698e13a ("io_uring: allow registering credentials")
Cc: stable@vger.kernel.org # 5.6+
Reported-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
[Pavel: rebased (creds load was moved into io_init_req())]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7ccff36e1375f2b0ebf73d957f037b43becc0dde.1615212806.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:42 -07:00
Pavel Begunkov
0298ef969a io_uring: clean R_DISABLED startup mess
There are enough of problems with IORING_SETUP_R_DISABLED, including the
burden of checking and kicking off the SQO task all over the codebase --
for exit/cancel/etc.

Rework it, always start the thread but don't do submit unless the flag
is gone, that's much easier.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:42 -07:00
Pavel Begunkov
f458dd8441 io_uring: fix unrelated ctx reqs cancellation
io-wq now is per-task, so cancellations now should match against
request's ctx.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:42 -07:00
Jens Axboe
05962f95f9 io_uring: SQPOLL parking fixes
We keep running into weird dependency issues between the sqd lock and
the parking state. Disentangle the SQPOLL thread from the last bits of
the kthread parking inheritance, and just replace the parking state,
and two associated locks, with a single rw mutex. The SQPOLL thread
keeps the mutex for read all the time, except if someone has marked us
needing to park. Then we drop/re-acquire and try again.

This greatly simplifies the parking state machine (by just getting rid
of it), and makes it a lot more obvious how it works - if you need to
modify the ctx list, then you simply park the thread which will grab
the lock for writing.

Fold in fix from Hillf Danton on not setting STOP on a fatal signal.

Fixes: e54945ae94 ("io_uring: SQPOLL stop error handling fixes")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-10 07:28:22 -07:00
Stefan Metzmacher
041474885e io_uring: kill io_sq_thread_fork() and return -EOWNERDEAD if the sq_thread is gone
This brings the behavior back in line with what 5.11 and earlier did,
and this is no longer needed with the improved handling of creds
not needing to do unshare().

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Stefan Metzmacher
7c30f36a98 io_uring: run __io_sq_thread() with the initial creds from io_uring_setup()
With IORING_SETUP_ATTACH_WQ we should let __io_sq_thread() use the
initial creds from each ctx.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Pavel Begunkov
678eeba481 io-wq: warn on creating manager while exiting
Add a simple warning making sure that nobody tries to create a new
manager while we're under IO_WQ_BIT_EXIT. That can potentially happen
due to racy work submission after final put.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Pavel Begunkov
1b00764f09 io_uring: cancel reqs of all iowq's on ring exit
io_ring_exit_work() have to cancel all requests, including those staying
in io-wq, however it tries only cancellation of current tctx, which is
NULL. If we've got task==NULL, use the ctx-to-tctx map to go over all
tctx/io-wq and try cancellations on them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Pavel Begunkov
b5bb3a24f6 io_uring: warn when ring exit takes too long
We use system_unbound_wq to run io_ring_exit_work(), so it's hard to
monitor whether removal hang or not. Add WARN_ONCE to catch hangs.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Pavel Begunkov
baf186c4d3 io_uring: index io_uring->xa by ctx not file
We don't use task file notes anymore, and no need left in indexing
task->io_uring->xa by file, and replace it with ctx. It's better
design-wise, especially since we keep a dangling file, and so have to
keep an eye on not dereferencing it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Pavel Begunkov
eebd2e37e6 io_uring: don't take task ring-file notes
With ->flush() gone we're now leaving all uring file notes until the
task dies/execs, so the ctx will not be freed until all tasks that have
ever submit a request die. It was nicer with flush but not much, we
could have locked as described ctx in many cases.

Now we guarantee that ctx outlives all tctx in a sense that
io_ring_exit_work() waits for all tctxs to drop their corresponding
enties in ->xa, and ctx won't go away until then. Hence, additional
io_uring file reference (a.k.a. task file notes) are not needed anymore.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Pavel Begunkov
d56d938b4b io_uring: do ctx initiated file note removal
Another preparation patch. When full quiesce is done on ctx exit, use
task_work infra to remove corresponding to the ctx io_uring->xa entries.
For that we use the back tctx map. Also use ->in_idle to prevent
removing it while we traversing ->xa on cancellation, just ignore it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Pavel Begunkov
13bf43f5f4 io_uring: introduce ctx to tctx back map
For each pair tcxt-ctx create an object and chain it into ctx, so we
have a way to traverse all tctx that are using current ctx. Preparation
patch, will be used later.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Pavel Begunkov
2941267bd3 io_uring: make del_task_file more forgiving
Rework io_uring_del_task_file(), so it accepts an index to delete, and
it's not necessarily have to be in the ->xa. Infer file from xa_erase()
to maintain a single origin of truth.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-07 14:12:43 -07:00
Jens Axboe
003e8dccdb io-wq: always track creds for async issue
If we go async with a request, grab the creds that the task currently has
assigned and make sure that the async side switches to them. This is
handled in the same way that we do for registered personalities.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-06 10:57:01 -07:00
Jens Axboe
886d0137f1 io-wq: fix race in freeing 'wq' and worker access
Ran into a use-after-free on the main io-wq struct, wq. It has a worker
ref and completion event, but the manager itself isn't holding a
reference. This can lead to a race where the manager thinks there are
no workers and exits, but a worker is being added. That leads to the
following trace:

BUG: KASAN: use-after-free in io_wqe_worker+0x4c0/0x5e0
Read of size 8 at addr ffff888108baa8a0 by task iou-wrk-3080422/3080425

CPU: 5 PID: 3080425 Comm: iou-wrk-3080422 Not tainted 5.12.0-rc1+ #110
Hardware name: Micro-Star International Co., Ltd. MS-7C60/TRX40 PRO 10G (MS-7C60), BIOS 1.60 05/13/2020
Call Trace:
 dump_stack+0x90/0xbe
 print_address_description.constprop.0+0x67/0x28d
 ? io_wqe_worker+0x4c0/0x5e0
 kasan_report.cold+0x7b/0xd4
 ? io_wqe_worker+0x4c0/0x5e0
 __asan_load8+0x6d/0xa0
 io_wqe_worker+0x4c0/0x5e0
 ? io_worker_handle_work+0xc00/0xc00
 ? recalc_sigpending+0xe5/0x120
 ? io_worker_handle_work+0xc00/0xc00
 ? io_worker_handle_work+0xc00/0xc00
 ret_from_fork+0x1f/0x30

Allocated by task 3080422:
 kasan_save_stack+0x23/0x60
 __kasan_kmalloc+0x80/0xa0
 kmem_cache_alloc_node_trace+0xa0/0x480
 io_wq_create+0x3b5/0x600
 io_uring_alloc_task_context+0x13c/0x380
 io_uring_add_task_file+0x109/0x140
 __x64_sys_io_uring_enter+0x45f/0x660
 do_syscall_64+0x32/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 3080422:
 kasan_save_stack+0x23/0x60
 kasan_set_track+0x20/0x40
 kasan_set_free_info+0x24/0x40
 __kasan_slab_free+0xe8/0x120
 kfree+0xa8/0x400
 io_wq_put+0x14a/0x220
 io_wq_put_and_exit+0x9a/0xc0
 io_uring_clean_tctx+0x101/0x140
 __io_uring_files_cancel+0x36e/0x3c0
 do_exit+0x169/0x1340
 __x64_sys_exit+0x34/0x40
 do_syscall_64+0x32/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Have the manager itself hold a reference, and now both drop points drop
and complete if we hit zero, and the manager can unconditionally do a
wait_for_completion() instead of having a race between reading the ref
count and waiting if it was non-zero.

Fixes: fb3a1f6c74 ("io-wq: have manager wait for all workers to exit")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-06 10:57:01 -07:00
Linus Torvalds
8b24ef4478 pstore fixes for v5.12-rc2
- Rate-limit ECC warnings (Dmitry Osipenko)
 
 - Fix error path check for NULL (Tetsuo Handa)
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Merge tag 'pstore-v5.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore fixes from Kees Cook:

 - Rate-limit ECC warnings (Dmitry Osipenko)

 - Fix error path check for NULL (Tetsuo Handa)

* tag 'pstore-v5.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/ram: Rate-limit "uncorrectable error in header" message
  pstore: Fix warning in pstore_kill_sb()
2021-03-05 17:21:25 -08:00
Linus Torvalds
f292e8730a io_uring-5.12-2021-03-05
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Merge tag 'io_uring-5.12-2021-03-05' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "A bit of a mix between fallout from the worker change, cleanups and
  reductions now possible from that change, and fixes in general. In
  detail:

   - Fully serialize manager and worker creation, fixing races due to
     that.

   - Clean up some naming that had gone stale.

   - SQPOLL fixes.

   - Fix race condition around task_work rework that went into this
     merge window.

   - Implement unshare. Used for when the original task does unshare(2)
     or setuid/seteuid and friends, drops the original workers and forks
     new ones.

   - Drop the only remaining piece of state shuffling we had left, which
     was cred. Move it into issue instead, and we can drop all of that
     code too.

   - Kill f_op->flush() usage. That was such a nasty hack that we had
     out of necessity, we no longer need it.

   - Following from ->flush() removal, we can also drop various bits of
     ctx state related to SQPOLL and cancelations.

   - Fix an issue with IOPOLL retry, which originally was fallout from a
     filemap change (removing iov_iter_revert()), but uncovered an issue
     with iovec re-import too late.

   - Fix an issue with system suspend.

   - Use xchg() for fallback work, instead of cmpxchg().

   - Properly destroy io-wq on exec.

   - Add create_io_thread() core helper, and use that in io-wq and
     io_uring. This allows us to remove various silly completion events
     related to thread setup.

   - A few error handling fixes.

  This should be the grunt of fixes necessary for the new workers, next
  week should be quieter. We've got a pending series from Pavel on
  cancelations, and how tasks and rings are indexed. Outside of that,
  should just be minor fixes. Even with these fixes, we're still killing
  a net ~80 lines"

* tag 'io_uring-5.12-2021-03-05' of git://git.kernel.dk/linux-block: (41 commits)
  io_uring: don't restrict issue_flags for io_openat
  io_uring: make SQPOLL thread parking saner
  io-wq: kill hashed waitqueue before manager exits
  io_uring: clear IOCB_WAITQ for non -EIOCBQUEUED return
  io_uring: don't keep looping for more events if we can't flush overflow
  io_uring: move to using create_io_thread()
  kernel: provide create_io_thread() helper
  io_uring: reliably cancel linked timeouts
  io_uring: cancel-match based on flags
  io-wq: ensure all pending work is canceled on exit
  io_uring: ensure that threads freeze on suspend
  io_uring: remove extra in_idle wake up
  io_uring: inline __io_queue_async_work()
  io_uring: inline io_req_clean_work()
  io_uring: choose right tctx->io_wq for try cancel
  io_uring: fix -EAGAIN retry with IOPOLL
  io-wq: fix error path leak of buffered write hash map
  io_uring: remove sqo_task
  io_uring: kill sqo_dead and sqo submission halting
  io_uring: ignore double poll add on the same waitqueue head
  ...
2021-03-05 12:44:43 -08:00
Linus Torvalds
f09b04cc64 for-5.12-rc1-tag
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Merge tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "More regression fixes and stabilization.

  Regressions:

   - zoned mode
      - count zone sizes in wider int types
      - fix space accounting for read-only block groups

   - subpage: fix page tail zeroing

  Fixes:

   - fix spurious warning when remounting with free space tree

   - fix warning when creating a directory with smack enabled

   - ioctl checks for qgroup inheritance when creating a snapshot

   - qgroup
      - fix missing unlock on error path in zero range
      - fix amount of released reservation on error
      - fix flushing from unsafe context with open transaction,
        potentially deadlocking

   - minor build warning fixes"

* tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: zoned: do not account freed region of read-only block group as zone_unusable
  btrfs: zoned: use sector_t for zone sectors
  btrfs: subpage: fix the false data csum mismatch error
  btrfs: fix warning when creating a directory with smack enabled
  btrfs: don't flush from btrfs_delayed_inode_reserve_metadata
  btrfs: export and rename qgroup_reserve_meta
  btrfs: free correct amount of space in btrfs_delayed_inode_reserve_metadata
  btrfs: fix spurious free_space_tree remount warning
  btrfs: validate qgroup inherit for SNAP_CREATE_V2 ioctl
  btrfs: unlock extents in btrfs_zero_range in case of quota reservation errors
  btrfs: ref-verify: use 'inline void' keyword ordering
2021-03-05 12:21:14 -08:00
Pavel Begunkov
e45cff5885 io_uring: don't restrict issue_flags for io_openat
45d189c606 ("io_uring: replace force_nonblock with flags") did
something strange for io_openat() slicing all issue_flags but
IO_URING_F_NONBLOCK. Not a bug for now, but better to just forward the
flags.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-05 09:52:29 -07:00
Jens Axboe
86e0d6766c io_uring: make SQPOLL thread parking saner
We have this weird true/false return from parking, and then some of the
callers decide to look at that. It can lead to unbalanced parks and
sqd locking. Have the callers check the thread status once it's parked.
We know we have the lock at that point, so it's either valid or it's NULL.

Fix race with parking on thread exit. We need to be careful here with
ordering of the sdq->lock and the IO_SQ_THREAD_SHOULD_PARK bit.

Rename sqd->completion to sqd->parked to reflect that this is the only
thing this completion event doesn.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-05 08:44:39 -07:00
Jens Axboe
09ca6c40c2 io-wq: kill hashed waitqueue before manager exits
If we race with shutting down the io-wq context and someone queueing
a hashed entry, then we can exit the manager with it armed. If it then
triggers after the manager has exited, we can have a use-after-free where
io_wqe_hash_wake() attempts to wake a now gone manager process.

Move the killing of the hashed write queue into the manager itself, so
that we know we've killed it before the task exits.

Fixes: e941894eae ("io-wq: make buffered file write hashed work map per-ctx")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-05 08:44:09 -07:00
Jens Axboe
b5b0ecb736 io_uring: clear IOCB_WAITQ for non -EIOCBQUEUED return
The callback can only be armed, if we get -EIOCBQUEUED returned. It's
important that we clear the WAITQ bit for other cases, otherwise we can
queue for async retry and filemap will assume that we're armed and
return -EAGAIN instead of just blocking for the IO.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-05 08:43:09 -07:00
Jens Axboe
ca0a26511c io_uring: don't keep looping for more events if we can't flush overflow
It doesn't make sense to wait for more events to come in, if we can't
even flush the overflow we already have to the ring. Return -EBUSY for
that condition, just like we do for attempts to submit with overflow
pending.

Cc: stable@vger.kernel.org # 5.11
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-05 08:43:09 -07:00
Jens Axboe
46fe18b16c io_uring: move to using create_io_thread()
This allows us to do task creation and setup without needing to use
completions to try and synchronize with the starting thread. Get rid of
the old io_wq_fork_thread() wrapper, and the 'wq' and 'worker' startup
completion events - we can now do setup before the task is running.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-05 08:43:01 -07:00
Pavel Begunkov
dd59a3d595 io_uring: reliably cancel linked timeouts
Linked timeouts are fired asynchronously (i.e. soft-irq), and use
generic cancellation paths to do its stuff, including poking into io-wq.
The problem is that it's racy to access tctx->io_wq, as
io_uring_task_cancel() and others may be happening at this exact moment.
Mark linked timeouts with REQ_F_INLIFGHT for now, making sure there are
no timeouts before io-wq destraction.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-04 15:45:01 -07:00
Pavel Begunkov
b05a1bcd40 io_uring: cancel-match based on flags
Instead of going into request internals, like checking req->file->f_op,
do match them based on REQ_F_INFLIGHT, it's set only when we want it to
be reliably cancelled.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-04 15:44:50 -07:00
Naohiro Aota
badae9c869 btrfs: zoned: do not account freed region of read-only block group as zone_unusable
We migrate zone unusable bytes to read-only bytes when a block group is
set to read-only, and account all the free region as bytes_readonly.
Thus, we should not increase block_group->zone_unusable when the block
group is read-only.

Fixes: 169e0da91a ("btrfs: zoned: track unusable bytes for zones")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-04 16:16:58 +01:00