Commit Graph

966273 Commits

Author SHA1 Message Date
Pavel Begunkov
c1379e247a io_uring: move req preps out of io_issue_sqe()
All request preparations are done only during submission, reflect it in
the code by moving io_req_prep() much earlier into io_queue_sqe().

That's much cleaner, because it doen't expose bits to async code which
it won't ever use. Also it makes the interface harder to misuse, and
there are potential places for bugs.

For instance, __io_queue() doesn't clear @sqe before proceeding to a
next linked request, that could have been disastrous, but hopefully
there are linked requests IFF sqe==NULL, so not actually a bug.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov
bfe7655983 io_uring: decouple issuing and req preparation
io_issue_sqe() does two things at once, trying to prepare request and
issuing them. Split it in two and deduplicate with io_defer_prep().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov
73debe68b3 io_uring: remove nonblock arg from io_{rw}_prep()
All io_*_prep() functions including io_{read,write}_prep() are called
only during submission where @force_nonblock is always true. Don't keep
propagating it and instead remove the @force_nonblock argument
from prep() altogether.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov
a88fc40021 io_uring: set/clear IOCB_NOWAIT into io_read/write
Move setting IOCB_NOWAIT from io_prep_rw() into io_read()/io_write(), so
it's set/cleared in a single place. Also remove @force_nonblock
parameter from io_prep_rw().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov
2d199895d2 io_uring: remove F_NEED_CLEANUP check in *prep()
REQ_F_NEED_CLEANUP is set only by io_*_prep() and they're guaranteed to
be called only once, so there is no one who may have set the flag
before. Kill REQ_F_NEED_CLEANUP check in these *prep() handlers.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov
5b09e37e27 io_uring: io_kiocb_ppos() style change
Put brackets around bitwise ops in a complex expression

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:45 -06:00
Pavel Begunkov
291b2821e0 io_uring: simplify io_alloc_req()
Extract common code from if/else branches. That is cleaner and optimised
even better.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:45 -06:00
Jens Axboe
145cc8c665 io-wq: kill unused IO_WORKER_F_EXITING
This flag is no longer used, remove it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Hillf Danton
c4068bf898 io-wq: fix use-after-free in io_wq_worker_running
The smart syzbot has found a reproducer for the following issue:

 ==================================================================
 BUG: KASAN: use-after-free in instrument_atomic_write include/linux/instrumented.h:71 [inline]
 BUG: KASAN: use-after-free in atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline]
 BUG: KASAN: use-after-free in io_wqe_inc_running fs/io-wq.c:301 [inline]
 BUG: KASAN: use-after-free in io_wq_worker_running+0xde/0x110 fs/io-wq.c:613
 Write of size 4 at addr ffff8882183db08c by task io_wqe_worker-0/7771

 CPU: 0 PID: 7771 Comm: io_wqe_worker-0 Not tainted 5.9.0-rc4-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+0x198/0x1fd lib/dump_stack.c:118
  print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
  __kasan_report mm/kasan/report.c:513 [inline]
  kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
  check_memory_region_inline mm/kasan/generic.c:186 [inline]
  check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
  instrument_atomic_write include/linux/instrumented.h:71 [inline]
  atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline]
  io_wqe_inc_running fs/io-wq.c:301 [inline]
  io_wq_worker_running+0xde/0x110 fs/io-wq.c:613
  schedule_timeout+0x148/0x250 kernel/time/timer.c:1879
  io_wqe_worker+0x517/0x10e0 fs/io-wq.c:580
  kthread+0x3b5/0x4a0 kernel/kthread.c:292
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

 Allocated by task 7768:
  kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
  kasan_set_track mm/kasan/common.c:56 [inline]
  __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
  kmem_cache_alloc_node_trace+0x17b/0x3f0 mm/slab.c:3594
  kmalloc_node include/linux/slab.h:572 [inline]
  kzalloc_node include/linux/slab.h:677 [inline]
  io_wq_create+0x57b/0xa10 fs/io-wq.c:1064
  io_init_wq_offload fs/io_uring.c:7432 [inline]
  io_sq_offload_start fs/io_uring.c:7504 [inline]
  io_uring_create fs/io_uring.c:8625 [inline]
  io_uring_setup+0x1836/0x28e0 fs/io_uring.c:8694
  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

 Freed by task 21:
  kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
  kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
  kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
  __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
  __cache_free mm/slab.c:3418 [inline]
  kfree+0x10e/0x2b0 mm/slab.c:3756
  __io_wq_destroy fs/io-wq.c:1138 [inline]
  io_wq_destroy+0x2af/0x460 fs/io-wq.c:1146
  io_finish_async fs/io_uring.c:6836 [inline]
  io_ring_ctx_free fs/io_uring.c:7870 [inline]
  io_ring_exit_work+0x1e4/0x6d0 fs/io_uring.c:7954
  process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
  worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
  kthread+0x3b5/0x4a0 kernel/kthread.c:292
  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

 The buggy address belongs to the object at ffff8882183db000
  which belongs to the cache kmalloc-1k of size 1024
 The buggy address is located 140 bytes inside of
  1024-byte region [ffff8882183db000, ffff8882183db400)
 The buggy address belongs to the page:
 page:000000009bada22b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2183db
 flags: 0x57ffe0000000200(slab)
 raw: 057ffe0000000200 ffffea0008604c48 ffffea00086a8648 ffff8880aa040700
 raw: 0000000000000000 ffff8882183db000 0000000100000002 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  ffff8882183daf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  ffff8882183db000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 >ffff8882183db080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                       ^
  ffff8882183db100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8882183db180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ==================================================================

which is down to the comment below,

	/* all workers gone, wq exit can proceed */
	if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs))
		complete(&wqe->wq->done);

because there might be multiple cases of wqe in a wq and we would wait
for every worker in every wqe to go home before releasing wq's resources
on destroying.

To that end, rework wq's refcount by making it independent of the tracking
of workers because after all they are two different things, and keeping
it balanced when workers come and go. Note the manager kthread, like
other workers, now holds a grab to wq during its lifetime.

Finally to help destroy wq, check IO_WQ_BIT_EXIT upon creating worker
and do nothing for exiting wq.

Cc: stable@vger.kernel.org # v5.5+
Reported-by: syzbot+45fa0a195b941764e0f0@syzkaller.appspotmail.com
Reported-by: syzbot+9af99580130003da82b1@syzkaller.appspotmail.com
Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Joseph Qi
dbbe9c6424 io_uring: show sqthread pid and cpu in fdinfo
In most cases we'll specify IORING_SETUP_SQPOLL and run multiple
io_uring instances in a host. Since all sqthreads are named
"io_uring-sq", it's hard to distinguish the relations between
application process and its io_uring sqthread.
With this patch, application can get its corresponding sqthread pid
and cpu through show_fdinfo.
Steps:
1. Get io_uring fd first.
$ ls -l /proc/<pid>/fd | grep -w io_uring
2. Then get io_uring instance related info, including corresponding
sqthread pid and cpu.
$ cat /proc/<pid>/fdinfo/<io_uring_fd>

pos:	0
flags:	02000002
mnt_id:	13
SqThread:	6929
SqThreadCpu:	2
UserFiles:	1
    0: testfile
UserBufs:	0
PollList:

Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
[axboe: fixed for new shared SQPOLL]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Jens Axboe
af9c1a44f8 io_uring: process task work in io_uring_register()
We do this for CQ ring wait, in case task_work completions come in. We
should do the same in io_uring_register(), to avoid spurious -EINTR
if the ring quiescing ends up having to process task_work to complete
the operation

Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Dennis Zhou
91d8f5191e io_uring: add blkcg accounting to offloaded operations
There are a few operations that are offloaded to the worker threads. In
this case, we lose process context and end up in kthread context. This
results in ios to be not accounted to the issuing cgroup and
consequently end up as issued by root. Just like others, adopt the
personality of the blkcg too when issuing via the workqueues.

For the SQPOLL thread, it will live and attach in the inited cgroup's
context.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Jens Axboe
de2939388b io_uring: improve registered buffer accounting for huge pages
io_uring does account any registered buffer as pinned/locked memory, and
checks limit and fails if the given user doesn't have a big enough limit
to register the ranges specified. However, if huge pages are used, we
are potentially under-accounting the memory in terms of what gets pinned
on the vm side.

This patch rectifies that, by ensuring that we account the full size of
a compound page, regardless of how much of it is being registered. Huge
pages are not accounted mulitple times - if multiple sections of a huge
page is registered, then the page is only accounted once.

Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Zheng Bin
14db84110d io_uring: remove unneeded semicolon
Fixes coccicheck warning:

fs/io_uring.c:4242:13-14: Unneeded semicolon

Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Jens Axboe
e95eee2dee io_uring: cap SQ submit size for SQPOLL with multiple rings
In the spirit of fairness, cap the max number of SQ entries we'll submit
for SQPOLL if we have multiple rings. If we don't do that, we could be
submitting tons of entries for one ring, while others are waiting to get
service.

The value of 8 is somewhat arbitrarily chosen as something that allows
a fair bit of batching, without using an excessive time per ring.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Jens Axboe
e8c2bc1fb6 io_uring: get rid of req->io/io_async_ctx union
There's really no point in having this union, it just means that we're
always allocating enough room to cater to any command. But that's
pointless, as the ->io field is request type private anyway.

This gets rid of the io_async_ctx structure, and fills in the required
size in the io_op_defs[] instead.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Pavel Begunkov
4be1c61512 io_uring: kill extra user_bufs check
Testing ctx->user_bufs for NULL in io_import_fixed() is not neccessary,
because in that case ctx->nr_user_bufs would be zero, and the following
check would fail.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Pavel Begunkov
ab0b196ce5 io_uring: fix overlapped memcpy in io_req_map_rw()
When io_req_map_rw() is called from io_rw_prep_async(), it memcpy()
iorw->iter into itself. Even though it doesn't lead to an error, such a
memcpy()'s aliasing rules violation is considered to be a bad practise.

Inline io_req_map_rw() into io_rw_prep_async(). We don't really need any
remapping there, so it's much simpler than the generic implementation.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Pavel Begunkov
afb87658f8 io_uring: refactor io_req_map_rw()
Set rw->free_iovec to @iovec, that gives an identical result and stresses
that @iovec param rw->free_iovec play the same role.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Pavel Begunkov
f4bff104ff io_uring: simplify io_rw_prep_async()
Don't touch iter->iov and iov in between __io_import_iovec() and
io_req_map_rw(), the former function aleady sets it correctly, because it
creates one more case with NULL'ed iov to consider in io_req_map_rw().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
9055420072 io_uring: provide IORING_ENTER_SQ_WAIT for SQPOLL SQ ring waits
When using SQPOLL, applications can run into the issue of running out of
SQ ring entries because the thread hasn't consumed them yet. The only
option for dealing with that is checking later, or busy checking for the
condition.

Provide IORING_ENTER_SQ_WAIT if applications want to wait on this
condition.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
738277adc8 io_uring: mark io_uring_fops/io_op_defs as __read_mostly
These structures are never written, move them appropriately.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
aa06165de8 io_uring: enable IORING_SETUP_ATTACH_WQ to attach to SQPOLL thread too
We support using IORING_SETUP_ATTACH_WQ to share async backends between
rings created by the same process, this now also allows the same to
happen with SQPOLL. The setup procedure remains the same, the caller
sets io_uring_params->wq_fd to the 'parent' context, and then the newly
created ring will attach to that async backend.

This means that multiple rings can share the same SQPOLL thread, saving
resources.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
69fb21310f io_uring: base SQPOLL handling off io_sq_data
Remove the SQPOLL thread from the ctx, and use the io_sq_data as the
data structure we pass in. io_sq_data has a list of ctx's that we can
then iterate over and handle.

As of now we're ready to handle multiple ctx's, though we're still just
handling a single one after this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
534ca6d684 io_uring: split SQPOLL data into separate structure
Move all the necessary state out of io_ring_ctx, and into a new
structure, io_sq_data. The latter now deals with any state or
variables associated with the SQPOLL thread itself.

In preparation for supporting more than one io_ring_ctx per SQPOLL
thread.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
c8d1ba583f io_uring: split work handling part of SQPOLL into helper
This is done in preparation for handling more than one ctx, but it also
cleans up the code a bit since io_sq_thread() was a bit too unwieldy to
get a get overview on.

__io_sq_thread() is now the main handler, and it returns an enum sq_ret
that tells io_sq_thread() what it ended up doing. The parent then makes
a decision on idle, spinning, or work handling based on that.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
3f0e64d054 io_uring: move SQPOLL post-wakeup ring need wakeup flag into wake handler
We need to decouple the clearing on wakeup from the the inline schedule,
as that is going to be required for handling multiple rings in one
thread.

Wrap our wakeup handler so we can clear it when we get the wakeup, by
definition that is when we no longer need the flag set.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
6a7793828f io_uring: use private ctx wait queue entries for SQPOLL
This is in preparation to sharing the poller thread between rings. For
that we need per-ring wait_queue_entry storage, and we can't easily put
that on the stack if one thread is managing multiple rings.

We'll also be sharing the wait_queue_head across rings for the purposes
of wakeups, provide the usual private ring wait_queue_head for now but
make it a pointer so we can easily override it when sharing.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
ce71bfea20 fs: align IOCB_* flags with RWF_* flags
We have a set of flags that are shared between the two and inherired
in kiocb_set_rw_flags(), but we check and set these individually.
Reorder the IOCB flags so that the bottom part of the space is synced
with the RWF flag space, and then we can do them all in one mask and
set operation.

The only exception is RWF_SYNC, which needs to mark IOCB_SYNC and
IOCB_DSYNC. Do that one separately.

This shaves 15 bytes of text from kiocb_set_rw_flags() for me.

Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
e35afcf912 io_uring: io_sq_thread() doesn't need to flush signals
We're not handling signals by default in kernel threads, and we never
use TWA_SIGNAL for the SQPOLL thread internally. Hence we can never
have a signal pending, and we don't need to check for it (nor flush it).

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Sebastian Andrzej Siewior
95da846592 io_wq: Make io_wqe::lock a raw_spinlock_t
During a context switch the scheduler invokes wq_worker_sleeping() with
disabled preemption. Disabling preemption is needed because it protects
access to `worker->sleeping'. As an optimisation it avoids invoking
schedule() within the schedule path as part of possible wake up (thus
preempt_enable_no_resched() afterwards).

The io-wq has been added to the mix in the same section with disabled
preemption. This breaks on PREEMPT_RT because io_wq_worker_sleeping()
acquires a spinlock_t. Also within the schedule() the spinlock_t must be
acquired after tsk_is_pi_blocked() otherwise it will block on the
sleeping lock again while scheduling out.

While playing with `io_uring-bench' I didn't notice a significant
latency spike after converting io_wqe::lock to a raw_spinlock_t. The
latency was more or less the same.

In order to keep the spinlock_t it would have to be moved after the
tsk_is_pi_blocked() check which would introduce a branch instruction
into the hot path.

The lock is used to maintain the `work_list' and wakes one task up at
most.
Should io_wqe_cancel_pending_work() cause latency spikes, while
searching for a specific item, then it would need to drop the lock
during iterations.
revert_creds() is also invoked under the lock. According to debug
cred::non_rcu is 0. Otherwise it should be moved outside of the locked
section because put_cred_rcu()->free_uid() acquires a sleeping lock.

Convert io_wqe::lock to a raw_spinlock_t.c

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Stefano Garzarella
7e84e1c756 io_uring: allow disabling rings during the creation
This patch adds a new IORING_SETUP_R_DISABLED flag to start the
rings disabled, allowing the user to register restrictions,
buffers, files, before to start processing SQEs.

When IORING_SETUP_R_DISABLED is set, SQE are not processed and
SQPOLL kthread is not started.

The restrictions registration are allowed only when the rings
are disable to prevent concurrency issue while processing SQEs.

The rings can be enabled using IORING_REGISTER_ENABLE_RINGS
opcode with io_uring_register(2).

Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Stefano Garzarella
21b55dbc06 io_uring: add IOURING_REGISTER_RESTRICTIONS opcode
The new io_uring_register(2) IOURING_REGISTER_RESTRICTIONS opcode
permanently installs a feature allowlist on an io_ring_ctx.
The io_ring_ctx can then be passed to untrusted code with the
knowledge that only operations present in the allowlist can be
executed.

The allowlist approach ensures that new features added to io_uring
do not accidentally become available when an existing application
is launched on a newer kernel version.

Currently is it possible to restrict sqe opcodes, sqe flags, and
register opcodes.

IOURING_REGISTER_RESTRICTIONS can only be made once. Afterwards
it is not possible to change restrictions anymore.
This prevents untrusted code from removing restrictions.

Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Stefano Garzarella
9d4a75efa2 io_uring: use an enumeration for io_uring_register(2) opcodes
The enumeration allows us to keep track of the last
io_uring_register(2) opcode available.

Behaviour and opcodes names don't change.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
a3ec600540 io_uring: move io_uring_get_socket() into io_uring.h
Now we have a io_uring kernel header, move this definition out of fs.h
and into io_uring.h where it belongs.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe
9b82849215 io_uring: reference ->nsproxy for file table commands
If we don't get and assign the namespace for the async work, then certain
paths just don't work properly (like /dev/stdin, /proc/mounts, etc).
Anything that references the current namespace of the given task should
be assigned for async work on behalf of that task.

Cc: stable@vger.kernel.org # v5.5+
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe
0f2122045b io_uring: don't rely on weak ->files references
Grab actual references to the files_struct. To avoid circular references
issues due to this, we add a per-task note that keeps track of what
io_uring contexts a task has used. When the tasks execs or exits its
assigned files, we cancel requests based on this tracking.

With that, we can grab proper references to the files table, and no
longer need to rely on stashing away ring_fd and ring_file to check
if the ring_fd may have been closed.

Cc: stable@vger.kernel.org # v5.5+
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe
e6c8aa9ac3 io_uring: enable task/files specific overflow flushing
This allows us to selectively flush out pending overflows, depending on
the task and/or files_struct being passed in.

No intended functional changes in this patch.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe
76e1b6427f io_uring: return cancelation status from poll/timeout/files handlers
Return whether we found and canceled requests or not. This is in
preparation for using this information, no functional changes in this
patch.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe
e3bc8e9dad io_uring: unconditionally grab req->task
Sometimes we assign a weak reference to it, sometimes we grab a
reference to it. Clean this up and make it unconditional, and drop the
flag related to tracking this state.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe
2aede0e417 io_uring: stash ctx task reference for SQPOLL
We can grab a reference to the task instead of stashing away the task
files_struct. This is doable without creating a circular reference
between the ring fd and the task itself.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe
f573d38445 io_uring: move dropping of files into separate helper
No functional changes in this patch, prep patch for grabbing references
to the files_struct.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe
f3606e3a92 io_uring: allow timeout/poll/files killing to take task into account
We currently cancel these when the ring exits, and we cancel all of
them. This is in preparation for killing only the ones associated
with a given task.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe
0f07889691 Merge branch 'io_uring-5.9' into for-5.10/io_uring
* io_uring-5.9:
  io_uring: fix async buffered reads when readahead is disabled
  io_uring: fix potential ABBA deadlock in ->show_fdinfo()
  io_uring: always delete double poll wait entry on match
2020-09-30 20:32:25 -06:00
Jean-Philippe Brucker
3effc06a4d selftests/bpf: Fix alignment of .BTF_ids
Fix a build failure on arm64, due to missing alignment information for
the .BTF_ids section:

resolve_btfids.test.o: in function `test_resolve_btfids':
tools/testing/selftests/bpf/prog_tests/resolve_btfids.c:140:(.text+0x29c): relocation truncated to fit: R_AARCH64_LDST32_ABS_LO12_NC against `.BTF_ids'
ld: tools/testing/selftests/bpf/prog_tests/resolve_btfids.c:140: warning: one possible cause of this error is that the symbol is being referenced in the indicated code as if it had a larger alignment than was declared where it was defined

In vmlinux, the .BTF_ids section is aligned to 4 bytes by vmlinux.lds.h.
In test_progs however, .BTF_ids doesn't have alignment constraints. The
arm64 linker expects the btf_id_set.cnt symbol, a u32, to be naturally
aligned but finds it misaligned and cannot apply the relocation. Enforce
alignment of .BTF_ids to 4 bytes.

Fixes: cd04b04de1 ("selftests/bpf: Add set test to resolve_btfids")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/bpf/20200930093559.2120126-1-jean-philippe@linaro.org
2020-09-30 18:11:40 -07:00
David S. Miller
f2e834694b Merge branch 'drop_monitor-Convert-to-use-devlink-tracepoint'
Ido Schimmel says:

====================
drop_monitor: Convert to use devlink tracepoint

Drop monitor is able to monitor both software and hardware originated
drops. Software drops are monitored by having drop monitor register its
probe on the 'kfree_skb' tracepoint. Hardware originated drops are
monitored by having devlink call into drop monitor whenever it receives
a dropped packet from the underlying hardware.

This patch set converts drop monitor to monitor both software and
hardware originated drops in the same way - by registering its probe on
the relevant tracepoint.

In addition to drop monitor being more consistent, it is now also
possible to build drop monitor as module instead of as a builtin and
still monitor hardware originated drops. Initially, CONFIG_NET_DEVLINK
implied CONFIG_NET_DROP_MONITOR, but after commit def2fbffe6
("kconfig: allow symbols implied by y to become m") we can have
CONFIG_NET_DEVLINK=y and CONFIG_NET_DROP_MONITOR=m and hardware
originated drops will not be monitored.

Patch set overview:

Patch #1 adds a tracepoint in devlink for trap reports.

Patch #2 prepares probe functions in drop monitor for the new
tracepoint.

Patch #3 converts drop monitor to use the new tracepoint.

Patches #4-#6 perform cleanups after the conversion.

Patch #7 adds a test case for drop monitor. Both software originated
drops and hardware originated drops (using netdevsim) are tested.

Tested:

| CONFIG_NET_DEVLINK | CONFIG_NET_DROP_MONITOR | Build | SW drops | HW drops |
| -------------------|-------------------------|-------|----------|----------|
|          y         |            y            |   v   |     v    |     v    |
|          y         |            m            |   v   |     v    |     v    |
|          y         |            n            |   v   |     x    |     x    |
|          n         |            y            |   v   |     v    |     x    |
|          n         |            m            |   v   |     v    |     x    |
|          n         |            n            |   v   |     x    |     x    |
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:27 -07:00
Ido Schimmel
b7cc6d3c5c selftests: net: Add drop monitor test
Test that drop monitor correctly captures both software and hardware
originated packet drops.

# ./drop_monitor_tests.sh

Software drops test
    TEST: Capturing active software drops                               [ OK ]
    TEST: Capturing inactive software drops                             [ OK ]

Hardware drops test
    TEST: Capturing active hardware drops                               [ OK ]
    TEST: Capturing inactive hardware drops                             [ OK ]

Tests passed:   4
Tests failed:   0

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00
Ido Schimmel
93e155967c drop_monitor: Filter control packets in drop monitor
Previously, devlink called into drop monitor in order to report hardware
originated drops / exceptions. devlink intentionally filtered control
packets and did not pass them to drop monitor as they were not dropped
by the underlying hardware.

Now drop monitor registers its probe on a generic 'devlink_trap_report'
tracepoint and should therefore perform this filtering itself instead of
having devlink do that.

Add the trap type as metadata and have drop monitor ignore control
packets.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00
Ido Schimmel
a848c05f4b drop_monitor: Remove duplicate struct
'struct net_dm_hw_metadata' is a duplicate of 'struct
devlink_trap_metadata'.

Remove the former and simplify the code.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00
Ido Schimmel
de9cbb81bd drop_monitor: Remove no longer used functions
The old probe functions that were invoked by drop monitor code are no
longer called and can thus be removed. They were replaced by actual
probe functions that are registered on the recently introduced
'devlink_trap_report' tracepoint.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-30 18:01:26 -07:00