This is a note to let you know that I've just added the patch titled
fs/aio: Make io_cancel() generate completions again
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-aio-make-io_cancel-generate-completions-again.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 54cbc058d86beca3515c994039b5c0f0a34f53dd Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@xxxxxxx>
Date: Thu, 15 Feb 2024 12:47:39 -0800
Subject: fs/aio: Make io_cancel() generate completions again
From: Bart Van Assche <bvanassche@xxxxxxx>
commit 54cbc058d86beca3515c994039b5c0f0a34f53dd upstream.
The following patch accidentally removed the code for delivering
completions for cancelled reads and writes to user space: "[PATCH 04/33]
aio: remove retry-based AIO"
(https://lore.kernel.org/all/1363883754-27966-5-git-send-email-koverstreet@xxxxxxxxxx/)
>From that patch:
- if (kiocbIsCancelled(iocb)) {
- ret = -EINTR;
- aio_complete(iocb, ret, 0);
- /* must not access the iocb after this */
- goto out;
- }
This leads to a leak in user space of a struct iocb. Hence this patch
that restores the code that reports to user space that a read or write
has been cancelled successfully.
Fixes: 41003a7bcfed ("aio: remove retry-based AIO")
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxxxx>
Cc: Sandeep Dhavale <dhavale@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Link: https://lore.kernel.org/r/20240215204739.2677806-3-bvanassche@xxxxxxx
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/aio.c | 27 +++++++++++----------------
1 file changed, 11 insertions(+), 16 deletions(-)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -2131,14 +2131,11 @@ COMPAT_SYSCALL_DEFINE3(io_submit, compat
#endif
/* sys_io_cancel:
- * Attempts to cancel an iocb previously passed to io_submit. If
- * the operation is successfully cancelled, the resulting event is
- * copied into the memory pointed to by result without being placed
- * into the completion queue and 0 is returned. May fail with
- * -EFAULT if any of the data structures pointed to are invalid.
- * May fail with -EINVAL if aio_context specified by ctx_id is
- * invalid. May fail with -EAGAIN if the iocb specified was not
- * cancelled. Will fail with -ENOSYS if not implemented.
+ * Attempts to cancel an iocb previously passed to io_submit(). If the
+ * operation is successfully cancelled 0 is returned. May fail with
+ * -EFAULT if any of the data structures pointed to are invalid. May
+ * fail with -EINVAL if aio_context specified by ctx_id is invalid. Will
+ * fail with -ENOSYS if not implemented.
*/
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
struct io_event __user *, result)
@@ -2169,14 +2166,12 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t
}
spin_unlock_irq(&ctx->ctx_lock);
- if (!ret) {
- /*
- * The result argument is no longer used - the io_event is
- * always delivered via the ring buffer. -EINPROGRESS indicates
- * cancellation is progress:
- */
- ret = -EINPROGRESS;
- }
+ /*
+ * The result argument is no longer used - the io_event is always
+ * delivered via the ring buffer.
+ */
+ if (ret == 0 && kiocb->rw.ki_flags & IOCB_AIO_RW)
+ aio_complete_rw(&kiocb->rw, -EINTR);
percpu_ref_put(&ctx->users);
Patches currently in stable-queue which might be from bvanassche@xxxxxxx are
queue-4.19/fs-aio-make-io_cancel-generate-completions-again.patch
