This is a note to let you know that I've just added the patch titled
bio: return EINTR if copying to user space got interrupted
to the 3.14-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:
bio-return-eintr-if-copying-to-user-space-got-interrupted.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2d99b55d378c996b9692a0c93dd25f4ed5d58934 Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare@xxxxxxx>
Date: Fri, 12 Feb 2016 09:39:15 +0100
Subject: bio: return EINTR if copying to user space got interrupted
From: Hannes Reinecke <hare@xxxxxxx>
commit 2d99b55d378c996b9692a0c93dd25f4ed5d58934 upstream.
Commit 35dc248383bbab0a7203fca4d722875bc81ef091 introduced a check for
current->mm to see if we have a user space context and only copies data
if we do. Now if an IO gets interrupted by a signal data isn't copied
into user space any more (as we don't have a user space context) but
user space isn't notified about it.
This patch modifies the behaviour to return -EINTR from bio_uncopy_user()
to notify userland that a signal has interrupted the syscall, otherwise
it could lead to a situation where the caller may get a buffer with
no data returned.
This can be reproduced by issuing SG_IO ioctl()s in one thread while
constantly sending signals to it.
Fixes: 35dc248 [SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal
Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v.3.11+
Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/bio.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1096,9 +1096,12 @@ int bio_uncopy_user(struct bio *bio)
ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs,
bio_data_dir(bio) == READ,
0, bmd->is_our_pages);
- else if (bmd->is_our_pages)
- bio_for_each_segment_all(bvec, bio, i)
- __free_page(bvec->bv_page);
+ else {
+ ret = -EINTR;
+ if (bmd->is_our_pages)
+ bio_for_each_segment_all(bvec, bio, i)
+ __free_page(bvec->bv_page);
+ }
}
kfree(bmd);
bio_put(bio);
Patches currently in stable-queue which might be from hare@xxxxxxx are
queue-3.14/bio-return-eintr-if-copying-to-user-space-got-interrupted.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html