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linux/drivers/block
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Chenwandun f7daefe423 zram: fix race between backing_dev_show and backing_dev_store 
CPU0:				       CPU1:
backing_dev_show		       backing_dev_store
    ......				   ......
    file = zram->backing_dev;
    down_read(&zram->init_lock);	   down_read(&zram->init_init_lock)
    file_path(file, ...);		   zram->backing_dev = backing_dev;
    up_read(&zram->init_lock);		   up_read(&zram->init_lock);

gets the value of zram->backing_dev too early in backing_dev_show, which
resultin the value being NULL at the beginning, and not NULL later.

backtrace:
  d_path+0xcc/0x174
  file_path+0x10/0x18
  backing_dev_show+0x40/0xb4
  dev_attr_show+0x20/0x54
  sysfs_kf_seq_show+0x9c/0x10c
  kernfs_seq_show+0x28/0x30
  seq_read+0x184/0x488
  kernfs_fop_read+0x5c/0x1a4
  __vfs_read+0x44/0x128
  vfs_read+0xa0/0x138
  SyS_read+0x54/0xb4

Link: http://lkml.kernel.org/r/1571046839-16814-1-git-send-email-chenwandun@huawei.com
Signed-off-by: Chenwandun <chenwandun@huawei.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>	[4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-10-19 06:32:32 -04:00
..
aoe block: aoe: Fix kernel crash due to atomic sleep when exiting 2019-08-08 07:29:02 -06:00
drbd augmented rbtree: add new RB_DECLARE_CALLBACKS_MAX macro 2019-09-25 17:51:39 -07:00
mtip32xx block: mtip32xx: Remove call to memset after dma_alloc_coherent 2019-06-29 09:42:50 -06:00
paride paride/pcd: need to check if cd->disk is null in pcd_detect 2019-09-04 07:04:37 -06:00
rsxx rsxx: don't call dma_set_max_seg_size 2019-06-05 13:18:39 -06:00
xen-blkback xen/blkback: fix memory leaks 2019-08-12 08:18:37 -06:00
zram zram: fix race between backing_dev_show and backing_dev_store 2019-10-19 06:32:32 -04:00
amiflop.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
ataflop.c ataflop: Mark expected switch fall-through 2019-07-29 15:24:58 -06:00
brd.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
cryptoloop.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 30 2019-05-24 17:27:10 +02:00
floppy.c floppy: fix usercopy direction 2019-08-09 07:41:36 -06:00
Kconfig docs: blockdev: add it to the admin-guide 2019-07-15 11:03:01 -03:00
loop.c loop: change queue block size to match when using DIO 2019-10-01 09:36:01 -06:00
loop.h
Makefile
nbd.c nbd: fix possible sysfs duplicate warning 2019-10-10 09:44:56 -06:00
null_blk_main.c null_blk: format pr_* logs with pr_fmt 2019-09-16 08:38:29 -06:00
null_blk_zoned.c null_blk: Fix zoned command return code 2019-10-09 21:00:20 -06:00
null_blk.h null_blk: format pr_* logs with pr_fmt 2019-09-16 08:38:29 -06:00
pktcdvd.c pktcdvd: remove warning on attempting to register non-passthrough dev 2019-09-22 10:01:05 -06:00
ps3disk.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 164 2019-05-30 11:26:38 -07:00
ps3vram.c block/ps3vram: Use %llu to format sector_t after LBDAF removal 2019-06-13 03:17:50 -06:00
rbd_types.h rbd: support for object-map and fast-diff 2019-07-08 14:01:45 +02:00
rbd.c rbd: cancel lock_dwork if the wait is interrupted 2019-10-15 17:43:15 +02:00
skd_main.c Linux 5.2-rc6 2019-07-01 08:16:08 -06:00
skd_s1120.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
sunvdc.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
swim3.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
swim_asm.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
swim.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sx8.c
umem.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 349 2019-06-05 17:37:08 +02:00
umem.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 348 2019-06-05 17:37:08 +02:00
virtio_blk.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
xen-blkfront.c xen-blkfront: switch kcalloc to kvcalloc for large array allocation 2019-06-03 22:16:19 -04:00
xsysace.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
z2ram.c