redonkable/alistair23-linux
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alistair23-linux/drivers/md
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Coly Li a5f3d8a5ea bcache: use llist_for_each_entry_safe() in __closure_wake_up() 
Commit 09b3efec ("bcache: Don't reinvent the wheel but use existing llist
API") replaces the following while loop by llist_for_each_entry(),

-
-	while (reverse) {
-		cl = container_of(reverse, struct closure, list);
-		reverse = llist_next(reverse);
-
+	llist_for_each_entry(cl, reverse, list) {
 		closure_set_waiting(cl, 0);
 		closure_sub(cl, CLOSURE_WAITING + 1);
 	}

This modification introduces a potential race by iterating a corrupted
list. Here is how it happens.

In the above modification, closure_sub() may wake up a process which is
waiting on reverse list. If this process decides to wait again by calling
closure_wait(), its cl->list will be added to another wait list. Then
when llist_for_each_entry() continues to iterate next node, it will travel
on another new wait list which is added in closure_wait(), not the
original reverse list in __closure_wake_up(). It is more probably to
happen on UP machine because the waked up process may preempt the process
which wakes up it.

Use llist_for_each_entry_safe() will fix the issue, the safe version fetch
next node before waking up a process. Then the copy of next node will make
sure list iteration stays on original reverse list.

Fixes: 09b3efec81 ("bcache: Don't reinvent the wheel but use existing llist API")
Signed-off-by: Coly Li <colyli@suse.de>
Reported-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-27 14:54:49 -06:00
..
bcache bcache: use llist_for_each_entry_safe() in __closure_wake_up() 2017-09-27 14:54:49 -06:00
persistent-data dm space map disk: fix some book keeping in the disk space map 2017-05-15 15:09:50 -04:00
bitmap.c md/bitmap: disable bitmap_resize for file-backed bitmaps. 2017-08-31 22:57:03 -07:00
bitmap.h
dm-bio-prison-v1.c dm bio prison: use rb_entry() rather than container_of() 2017-06-19 11:03:50 -04:00
dm-bio-prison-v1.h block: switch bios to blk_status_t 2017-06-09 09:27:32 -06:00
dm-bio-prison-v2.c dm bio prison: use rb_entry() rather than container_of() 2017-06-19 11:03:50 -04:00
dm-bio-prison-v2.h
dm-bio-record.h block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-bufio.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-bufio.h dm integrity: optimize writing dm-bufio buffers that are partially changed 2017-08-28 11:47:17 -04:00
dm-builtin.c
dm-cache-background-tracker.c dm cache: handle kmalloc failure allocating background_tracker struct 2017-05-17 09:44:53 -04:00
dm-cache-background-tracker.h
dm-cache-block-types.h
dm-cache-metadata.c dm cache metadata: fail operations if fail_io mode has been established 2017-05-05 14:40:13 -04:00
dm-cache-metadata.h
dm-cache-policy-internal.h
dm-cache-policy-smq.c dm cache policy smq: don't do any writebacks unless IDLE 2017-05-14 21:54:33 -04:00
dm-cache-policy.c
dm-cache-policy.h
dm-cache-target.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-core.h dm: add basic support for using the select or poll function 2017-06-19 11:03:49 -04:00
dm-crypt.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-delay.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-era-target.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-exception-store.c
dm-exception-store.h
dm-flakey.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-integrity.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-io.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-ioctl.c dm ioctl: constify ioctl lookup table 2017-08-28 11:47:18 -04:00
dm-kcopyd.c dm kcopyd: add sequential write feature 2017-06-19 11:03:51 -04:00
dm-linear.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-log-userspace-base.c
dm-log-userspace-transfer.c
dm-log-userspace-transfer.h
dm-log-writes.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-log.c
dm-mpath.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-queue-length.c
dm-raid.c dm raid: bump target version 2017-07-25 14:54:20 -04:00
dm-raid1.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-region-hash.c
dm-round-robin.c
dm-rq.c dm rq: do not update rq partially in each ending bio 2017-08-28 10:23:28 -04:00
dm-rq.h dm rq: do not update rq partially in each ending bio 2017-08-28 10:23:28 -04:00
dm-service-time.c
dm-snap-persistent.c dm: make flush bios explicitly sync 2017-05-31 10:50:23 -04:00
dm-snap-transient.c
dm-snap.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-stats.c mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
dm-stats.h
dm-stripe.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-switch.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-sysfs.c
dm-table.c dm: constify argument arrays 2017-08-28 11:47:18 -04:00
dm-target.c dm: don't return errnos from ->map 2017-06-09 09:27:32 -06:00
dm-thin-metadata.c dm thin metadata: call precommit before saving the roots 2017-05-15 15:09:49 -04:00
dm-thin-metadata.h
dm-thin.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-uevent.c
dm-uevent.h
dm-verity-fec.c dm verity fec: fix GFP flags used with mempool_alloc() 2017-07-26 15:55:44 -04:00
dm-verity-fec.h
dm-verity-target.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm-verity.h
dm-zero.c dm: don't return errnos from ->map 2017-06-09 09:27:32 -06:00
dm-zoned-metadata.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-zoned-reclaim.c dm zoned: use GFP_NOIO in I/O path 2017-07-26 15:55:43 -04:00
dm-zoned-target.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-zoned.h dm zoned: drive-managed zoned block device target 2017-06-19 11:05:20 -04:00
dm.c - Some request-based DM core and DM multipath fixes and cleanups 2017-09-14 13:43:16 -07:00
dm.h
faulty.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
Kconfig dm zoned: drive-managed zoned block device target 2017-06-19 11:05:20 -04:00
linear.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
linear.h
Makefile dm zoned: drive-managed zoned block device target 2017-06-19 11:05:20 -04:00
md-cluster.c md-cluster: fix potential lock issue in add_new_disk 2017-05-21 20:37:09 -07:00
md-cluster.h
md.c Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-09-07 12:41:48 -07:00
md.h Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-09-07 12:41:48 -07:00
multipath.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
multipath.h
raid0.c Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-09-07 12:41:48 -07:00
raid0.h
raid1-10.c md: raid1-10: move raid1/raid10 common code into raid1-10.c 2017-07-21 12:47:20 -07:00
raid1.c Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-09-07 12:41:48 -07:00
raid1.h
raid5-cache.c Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-09-07 12:41:48 -07:00
raid5-log.h md/r5cache: gracefully handle journal device errors for writeback mode 2017-05-11 22:11:11 -07:00
raid5-ppl.c Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-09-07 12:41:48 -07:00
raid5.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-09-19 08:39:32 -07:00
raid5.h - A major update for DM cache that reduces the latency for deciding 2017-05-03 10:31:20 -07:00
raid10.c Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-09-07 12:41:48 -07:00
raid10.h