path: root/block
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authorHannes Reinecke <>2016-02-12 09:39:15 +0100
committerJens Axboe <>2016-02-12 08:17:41 -0700
commit2d99b55d378c996b9692a0c93dd25f4ed5d58934 (patch)
tree56a6454c8f7e68e8244be8ecd90f6208b5ae5315 /block
parentf8e68a7c9af5f8047f7f8295874bedf306063709 (diff)
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 <> Signed-off-by: Hannes Reinecke <> Cc: # v.3.11+ Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block')
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)