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authorHannes Reinecke <hare@suse.de>2016-02-12 09:39:15 +0100
committerJiri Slaby <jslaby@suse.cz>2016-03-04 09:48:15 +0100
commit7b1db06ff530bd1fa18e492ba61c5f7dc4e181a4 (patch)
treeb168dc3196d51b48b05de651ba245762707086fc
parent1e719417f896f35e25e27e974a4f1bbffb87b4c1 (diff)
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. [js] backport to 3.12 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> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
-rw-r--r--fs/bio.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/bio.c b/fs/bio.c
index e7fb3f82f5f5..6405b44000cb 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1051,15 +1051,19 @@ 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)
ret = __bio_copy_iov(bio, bmd->iovecs, 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);
+ }
}
bio_free_map_data(bmd);
bio_put(bio);