* FAILED: patch "[PATCH] io_uring: don't use poll handler if file can't be nonblocking" failed to apply to 5.8-stable tree
@ 2020-08-31 9:58 gregkh
2020-08-31 13:46 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: gregkh @ 2020-08-31 9:58 UTC (permalink / raw)
To: axboe, wisp3rwind; +Cc: stable
The patch below does not apply to the 5.8-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 9dab14b81807a40dab8e464ec87043935c562c2c Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Tue, 25 Aug 2020 12:27:50 -0600
Subject: [PATCH] io_uring: don't use poll handler if file can't be nonblocking
read/written
There's no point in using the poll handler if we can't do a nonblocking
IO attempt of the operation, since we'll need to go async anyway. In
fact this is actively harmful, as reading from eg pipes won't return 0
to indicate EOF.
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Benedikt Ames <wisp3rwind@posteo.eu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 384df86dfc69..d15139088e4c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4889,12 +4889,20 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
struct async_poll *apoll;
struct io_poll_table ipt;
__poll_t mask, ret;
+ int rw;
if (!req->file || !file_can_poll(req->file))
return false;
if (req->flags & REQ_F_POLLED)
return false;
- if (!def->pollin && !def->pollout)
+ if (def->pollin)
+ rw = READ;
+ else if (def->pollout)
+ rw = WRITE;
+ else
+ return false;
+ /* if we can't nonblock try, then no point in arming a poll handler */
+ if (!io_file_supports_async(req->file, rw))
return false;
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: FAILED: patch "[PATCH] io_uring: don't use poll handler if file can't be nonblocking" failed to apply to 5.8-stable tree
2020-08-31 9:58 FAILED: patch "[PATCH] io_uring: don't use poll handler if file can't be nonblocking" failed to apply to 5.8-stable tree gregkh
@ 2020-08-31 13:46 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2020-08-31 13:46 UTC (permalink / raw)
To: gregkh, wisp3rwind; +Cc: stable
On 8/31/20 3:58 AM, gregkh@linuxfoundation.org wrote:
>
> The patch below does not apply to the 5.8-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
Here's a backport:
From 84f81565a00f353c503d5b5bd98c77625af73b60 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Tue, 25 Aug 2020 12:27:50 -0600
Subject: [PATCH 2/3] io_uring: don't use poll handler if file can't be
nonblocking read/written
There's no point in using the poll handler if we can't do a nonblocking
IO attempt of the operation, since we'll need to go async anyway. In
fact this is actively harmful, as reading from eg pipes won't return 0
to indicate EOF.
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Benedikt Ames <wisp3rwind@posteo.eu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index c384caad6466..2b7018456091 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4503,12 +4503,20 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
struct async_poll *apoll;
struct io_poll_table ipt;
__poll_t mask, ret;
+ int rw;
if (!req->file || !file_can_poll(req->file))
return false;
if (req->flags & (REQ_F_MUST_PUNT | REQ_F_POLLED))
return false;
- if (!def->pollin && !def->pollout)
+ if (def->pollin)
+ rw = READ;
+ else if (def->pollout)
+ rw = WRITE;
+ else
+ return false;
+ /* if we can't nonblock try, then no point in arming a poll handler */
+ if (!io_file_supports_async(req->file, rw))
return false;
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
--
2.28.0
--
Jens Axboe
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2020-08-31 13:46 ` Jens Axboe
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