io_uring: fix ltout double free on completion race

mainline inclusion
from mainline-v5.13-rc2
commit 447c19f3
category: bugfix
bugzilla: 185823 https://gitee.com/openeuler/kernel/issues/I4DDEL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=447c19f3b5074409c794b350b10306e1da1ef4ba



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Always remove linked timeout on io_link_timeout_fn() from the master
request link list, otherwise we may get use-after-free when first
io_link_timeout_fn() puts linked timeout in the fail path, and then
will be found and put on master's free.

Cc: stable@vger.kernel.org # 5.10+
Fixes: 90cd7e42 ("io_uring: track link timeout's master explicitly")
Reported-and-tested-by:  <syzbot+5a864149dd970b546223@syzkaller.appspotmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/69c46bf6ce37fec4fdcd98f0882e18eb07ce693a.1620990121.git.asml.silence@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

conflicts:
fs/io_uring.c

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>