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| author | Hannes Reinecke <hare@suse.de> | 2016-02-12 09:39:15 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2016-02-12 08:17:41 -0700 |
| commit | 2d99b55d378c996b9692a0c93dd25f4ed5d58934 (patch) | |
| tree | 56a6454c8f7e68e8244be8ecd90f6208b5ae5315 /block/bio.c | |
| parent | f8e68a7c9af5f8047f7f8295874bedf306063709 (diff) | |
| download | lwn-2d99b55d378c996b9692a0c93dd25f4ed5d58934.tar.gz lwn-2d99b55d378c996b9692a0c93dd25f4ed5d58934.zip | |
bio: return EINTR if copying to user space got interrupted
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@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: stable@vger.kernel.org # v.3.11+
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/bio.c')
| -rw-r--r-- | block/bio.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/block/bio.c b/block/bio.c index f53a691b6533..cf7591551b17 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1090,9 +1090,12 @@ int bio_uncopy_user(struct bio *bio) if (!bio_flagged(bio, BIO_NULL_MAPPED)) { /* * if we're in a workqueue, the request is orphaned, so - * don't copy into a random user address space, just free. + * don't copy into a random user address space, just free + * and return -EINTR so user space doesn't expect any data. */ - if (current->mm && bio_data_dir(bio) == READ) + if (!current->mm) + ret = -EINTR; + else if (bio_data_dir(bio) == READ) ret = bio_copy_to_iter(bio, bmd->iter); if (bmd->is_our_pages) bio_free_pages(bio); |