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| author | Hannes Reinecke <hare@suse.de> | 2016-02-12 09:39:15 +0100 |
|---|---|---|
| committer | Luis Henriques <luis.henriques@canonical.com> | 2016-03-04 10:26:40 +0000 |
| commit | 04e0f4eebfe7419444dd5dd7ea476a7b25030054 (patch) | |
| tree | e08b7bdcbecac6052e8cffe9e4ed8c43ab69a38d | |
| parent | ce6288ccdf8e0c8c24bf3fc0375608f37de19c7e (diff) | |
| download | linux-stable-04e0f4eebfe7419444dd5dd7ea476a7b25030054.tar.gz linux-stable-04e0f4eebfe7419444dd5dd7ea476a7b25030054.tar.bz2 linux-stable-04e0f4eebfe7419444dd5dd7ea476a7b25030054.zip | |
bio: return EINTR if copying to user space got interrupted
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@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
[ luis: backported to 3.16: based on Johannes' backport to 3.14 ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
| -rw-r--r-- | block/bio.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/block/bio.c b/block/bio.c index 6467e6afdcd9..529e4195724e 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1110,9 +1110,12 @@ 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); |