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authorJens Axboe <axboe@kernel.dk>2019-12-18 12:19:41 -0700
committerJens Axboe <axboe@kernel.dk>2019-12-18 12:19:41 -0700
commitfd6c2e4c063d64511657ad0031a1677b6a914859 (patch)
tree7430a804ec01e1495d291353ad398b272e45d9cb /fs
parent7c504e65206a4379ff38fe41d21b32b6c2c3e53e (diff)
io_uring: io_wq_submit_work() should not touch req->rw
I've been chasing a weird and obscure crash that was userspace stack corruption, and finally narrowed it down to a bit flip that made a stack address invalid. io_wq_submit_work() unconditionally flips the req->rw.ki_flags IOCB_NOWAIT bit, but since it's a generic work handler, this isn't valid. Normal read/write operations own that part of the request, on other types it could be something else. Move the IOCB_NOWAIT clear to the read/write handlers where it belongs. Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
-rw-r--r--fs/io_uring.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 81e7fe6dee18..6f084e3cf835 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1817,6 +1817,10 @@ static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
return ret;
}
+ /* Ensure we clear previously set non-block flag */
+ if (!force_nonblock)
+ req->rw.ki_flags &= ~IOCB_NOWAIT;
+
file = req->file;
io_size = ret;
if (req->flags & REQ_F_LINK)
@@ -1906,6 +1910,10 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
return ret;
}
+ /* Ensure we clear previously set non-block flag */
+ if (!force_nonblock)
+ req->rw.ki_flags &= ~IOCB_NOWAIT;
+
file = kiocb->ki_filp;
io_size = ret;
if (req->flags & REQ_F_LINK)
@@ -3274,9 +3282,6 @@ static void io_wq_submit_work(struct io_wq_work **workptr)
struct io_kiocb *nxt = NULL;
int ret = 0;
- /* Ensure we clear previously set non-block flag */
- req->rw.ki_flags &= ~IOCB_NOWAIT;
-
if (work->flags & IO_WQ_WORK_CANCEL)
ret = -ECANCELED;