korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-13 22:14:20 +08:00
Code Issues Packages Projects Releases Wiki Activity

io_uring: fix locking state for empty buffer group

Browse Source 
io_provided_buffer_select() must drop the submit lock, if needed, even
in the error handling case. Failure to do so will leave us with the
ctx->uring_lock held, causing spew like:

====================================
WARNING: iou-wrk-366/368 still has locks held!
5.18.0-rc6-00294-gdf8dc7004331 #994 Not tainted
------------------------------------
1 lock held by iou-wrk-366/368:
 #0: ffff0000c72598a8 (&ctx->uring_lock){+.+.}-{3:3}, at: io_ring_submit_lock+0x20/0x48

stack backtrace:
CPU: 4 PID: 368 Comm: iou-wrk-366 Not tainted 5.18.0-rc6-00294-gdf8dc7004331 #994
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace.part.0+0xa4/0xd4
 show_stack+0x14/0x5c
 dump_stack_lvl+0x88/0xb0
 dump_stack+0x14/0x2c
 debug_check_no_locks_held+0x84/0x90
 try_to_freeze.isra.0+0x18/0x44
 get_signal+0x94/0x6ec
 io_wqe_worker+0x1d8/0x2b4
 ret_from_fork+0x10/0x20

and triggering later hangs off get_signal() because we attempt to
re-grab the lock.

Reported-by: syzbot+987d7bb19195ae45208c@syzkaller.appspotmail.com
Fixes: 149c69b04a ("io_uring: abstract out provided buffer list selection")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2022-05-15 11:19:43 -06:00
parent 4e86a2c980
commit e7637a492b
1 changed files with 14 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
fs/io_uring.c
View File

@ -3467,20 +3467,23 @@ static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len,
struct io_buffer_list *bl,
unsigned int issue_flags)
{
struct io_buffer *kbuf;
void __user *ret = ERR_PTR(-ENOBUFS);
if (list_empty(&bl->buf_list))
return ERR_PTR(-ENOBUFS);
if (!list_empty(&bl->buf_list)) {
struct io_buffer *kbuf;
kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list);
list_del(&kbuf->list);
if (*len > kbuf->len)
*len = kbuf->len;
req->flags |= REQ_F_BUFFER_SELECTED;
req->kbuf = kbuf;
req->buf_index = kbuf->bid;
ret = u64_to_user_ptr(kbuf->addr);
}
kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list);
list_del(&kbuf->list);
if (*len > kbuf->len)
*len = kbuf->len;
req->flags |= REQ_F_BUFFER_SELECTED;
req->kbuf = kbuf;
req->buf_index = kbuf->bid;
io_ring_submit_unlock(req->ctx, issue_flags);
return u64_to_user_ptr(kbuf->addr);
return ret;
}
static void __user *io_buffer_select(struct io_kiocb *req, size_t *len,