From b8ce1b9d25ccf81e1bbabd45b963ed98b2222df8 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue, 31 Aug 2021 14:13:11 +0100
Subject: [PATCH] io_uring: don't submit half-prepared drain request
Git-commit: b8ce1b9d25ccf81e1bbabd45b963ed98b2222df8
Patch-mainline: v5.15-rc1
References: bsc#1205205
[ 3784.910888] BUG: kernel NULL pointer dereference, address: 0000000000000020
[ 3784.910904] RIP: 0010:__io_file_supports_nowait+0x5/0xc0
[ 3784.910926] Call Trace:
[ 3784.910928] ? io_read+0x17c/0x480
[ 3784.910945] io_issue_sqe+0xcb/0x1840
[ 3784.910953] __io_queue_sqe+0x44/0x300
[ 3784.910959] io_req_task_submit+0x27/0x70
[ 3784.910962] tctx_task_work+0xeb/0x1d0
[ 3784.910966] task_work_run+0x61/0xa0
[ 3784.910968] io_run_task_work_sig+0x53/0xa0
[ 3784.910975] __x64_sys_io_uring_enter+0x22/0x30
[ 3784.910977] do_syscall_64+0x3d/0x90
[ 3784.910981] entry_SYSCALL_64_after_hwframe+0x44/0xae
io_drain_req() goes before checks for REQ_F_FAIL, which protect us from
submitting under-prepared request (e.g. failed in io_init_req(). Fail
such drained requests as well.
Fixes: a8295b982c46d ("io_uring: fix failed linkchain code logic")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e411eb9924d47a131b1e200b26b675df0c2b7627.1630415423.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
fs/io_uring.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 78f3d3ac2280..4a5eb9e856f0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6238,6 +6238,11 @@ static bool io_drain_req(struct io_kiocb *req)
int ret;
u32 seq;
+ if (req->flags & REQ_F_FAIL) {
+ io_req_complete_fail_submit(req);
+ return true;
+ }
+
/*
* If we need to drain a request in the middle of a link, drain the
* head request and the next request/link after the current link.
--
2.35.3