linux-toradex.git/io_uring/msg_ring.c, branch v6.2-rc2

io_uring/msg_ring: flag target ring as having task_work, if needed

2022-12-08T16:36:02+00:00

Before the recent change, we didn't even wake the targeted task when
posting the cqe remotely. Now we do wake it, but we do want to ensure
that the recipient knows there's potential work there that needs to
get processed to get the CQE posted.

OR in IORING_SQ_TASKRUN for that purpose.

Link: https://lore.kernel.org/io-uring/2843c6b4-ba9a-b67d-e0f4-957f42098489@kernel.dk/
Fixes: 6d043ee1164c ("io_uring: do msg_ring in target task via tw")
Signed-off-by: Jens Axboe

io_uring: do msg_ring in target task via tw

2022-12-07T15:50:57+00:00

While executing in a context of one io_uring instance msg_ring
manipulates another ring. We're trying to keep CQEs posting contained in
the context of the ring-owner task, use task_work to send the request to
the target ring's task when we're modifying its CQ or trying to install
a file. Note, we can't safely use io_uring task_work infra and have to
use task_work directly.

Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/4d76c7b28ed5d71b520de4482fbb7f660f21cd80.1670384893.git.asml.silence@gmail.com
[axboe: use TWA_SIGNAL_NO_IPI]
Signed-off-by: Jens Axboe

io_uring: extract a io_msg_install_complete helper

2022-12-07T13:47:13+00:00

Extract a helper called io_msg_install_complete() from io_msg_send_fd(),
will be used later.

Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/1500ca1054cc4286a3ee1c60aacead57fcdfa02a.1670384893.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

io_uring: get rid of double locking

2022-12-07T13:47:13+00:00

We don't need to take both uring_locks at once, msg_ring can be split in
two parts, first getting a file from the filetable of the first ring and
then installing it into the second one.

Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/a80ecc2bc99c3b3f2cf20015d618b7c51419a797.1670384893.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

io_uring: improve io_double_lock_ctx fail handling

2022-12-07T13:47:13+00:00

msg_ring will fail the request if it can't lock rings, instead punt it
to io-wq as was originally intended.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/4697f05afcc37df5c8f89e2fe6d9c7c19f0241f9.1670384893.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

io_uring: dont remove file from msg_ring reqs

2022-12-07T13:47:13+00:00

We should not be messing with req->file outside of core paths. Clearing
it makes msg_ring non reentrant, i.e. luckily io_msg_send_fd() fails the
request on failed io_double_lock_ctx() but clearly was originally
intended to do retries instead.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/e5ac9edadb574fe33f6d727cb8f14ce68262a684.1670384893.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

io_uring: remove overflow param from io_post_aux_cqe

2022-11-25T13:10:04+00:00

The only call sites which would not allow overflow are also call sites
which would use the io_aux_cqe as they care about ordering.

So remove this parameter from io_post_aux_cqe.

Signed-off-by: Dylan Yudaken 
Link: https://lore.kernel.org/r/20221124093559.3780686-9-dylany@meta.com
Signed-off-by: Jens Axboe

io_uring/msg_ring: Fix NULL pointer dereference in io_msg_send_fd()

2022-10-19T19:33:33+00:00

Syzkaller produced the below call trace:

 BUG: KASAN: null-ptr-deref in io_msg_ring+0x3cb/0x9f0
 Write of size 8 at addr 0000000000000070 by task repro/16399

 CPU: 0 PID: 16399 Comm: repro Not tainted 6.1.0-rc1 #28
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7
 Call Trace:
  
  dump_stack_lvl+0xcd/0x134
  ? io_msg_ring+0x3cb/0x9f0
  kasan_report+0xbc/0xf0
  ? io_msg_ring+0x3cb/0x9f0
  kasan_check_range+0x140/0x190
  io_msg_ring+0x3cb/0x9f0
  ? io_msg_ring_prep+0x300/0x300
  io_issue_sqe+0x698/0xca0
  io_submit_sqes+0x92f/0x1c30
  __do_sys_io_uring_enter+0xae4/0x24b0
....
 RIP: 0033:0x7f2eaf8f8289
 RSP: 002b:00007fff40939718 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2eaf8f8289
 RDX: 0000000000000000 RSI: 0000000000006f71 RDI: 0000000000000004
 RBP: 00007fff409397a0 R08: 0000000000000000 R09: 0000000000000039
 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004006d0
 R13: 00007fff40939880 R14: 0000000000000000 R15: 0000000000000000
  
 Kernel panic - not syncing: panic_on_warn set ...

We don't have a NULL check on file_ptr in io_msg_send_fd() function,
so when file_ptr is NUL src_file is also NULL and get_file()
dereferences a NULL pointer and leads to above crash.

Add a NULL check to fix this issue.

Fixes: e6130eba8a84 ("io_uring: add support for passing fixed file descriptors")
Reported-by: syzkaller 
Signed-off-by: Harshit Mogalapalli 
Link: https://lore.kernel.org/r/20221019171218.1337614-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Jens Axboe

io_uring/msg_ring: check file type before putting

2022-09-15T17:44:35+00:00

If we're invoked with a fixed file, follow the normal rules of not
calling io_fput_file(). Fixed files are permanently registered to the
ring, and do not need putting separately.

Cc: stable@vger.kernel.org
Fixes: aa184e8671f0 ("io_uring: don't attempt to IOPOLL for MSG_RING requests")
Signed-off-by: Jens Axboe

io_uring: make io_kiocb_to_cmd() typesafe

2022-08-12T23:01:00+00:00

We need to make sure (at build time) that struct io_cmd_data is not
casted to a structure that's larger.

Signed-off-by: Stefan Metzmacher 
Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org
Signed-off-by: Jens Axboe