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BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 block/genhd.c:1550
Read of size 8 at addr ffff8801cc4540e0 by task syz-executor291/2164
CPU: 0 PID: 2164 Comm: syz-executor291 Not tainted 4.9.168+ #39
ffff8801ce107730 ffffffff81b4f5d1 0000000000000000 ffffea0007311400
ffff8801cc4540e0 0000000000000008 ffffffff81b21b35 ffff8801ce107768
ffffffff81506898 0000000000000000 ffff8801cc4540e0 ffff8801cc4540e0
Call Trace:
[<000000006dc8c4a2>] __dump_stack lib/dump_stack.c:15 [inline]
[<000000006dc8c4a2>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
[<000000003c457958>] print_address_description+0x6f/0x23a mm/kasan/report.c:256
[<00000000d9f3850b>] kasan_report_error mm/kasan/report.c:355 [inline]
[<00000000d9f3850b>] kasan_report mm/kasan/report.c:412 [inline]
[<00000000d9f3850b>] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:397
[<000000006e90d85a>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
[<000000003a61945f>] disk_unblock_events+0x55/0x60 block/genhd.c:1550
[<0000000040085563>] __blkdev_get+0x6ba/0xeb0 fs/block_dev.c:1368
[<000000004d3c7164>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424
[<00000000339bbf96>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579
[<00000000a3f816e7>] do_dentry_open+0x422/0xd20 fs/open.c:772
[<000000005253ff23>] vfs_open+0x105/0x230 fs/open.c:885
[<000000005b95cf81>] do_last fs/namei.c:3457 [inline]
[<000000005b95cf81>] path_openat+0xbf5/0x2f60 fs/namei.c:3581
[<00000000513a3326>] do_filp_open+0x1a1/0x280 fs/namei.c:3615
[<00000000017a994a>] do_sys_open+0x2f0/0x610 fs/open.c:1078
[<00000000719e23f6>] SYSC_open fs/open.c:1096 [inline]
[<00000000719e23f6>] SyS_open+0x2d/0x40 fs/open.c:1091
[<00000000e3e65051>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
[<000000004b1db9aa>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Allocated by task 2169:
save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
save_stack mm/kasan/kasan.c:505 [inline]
set_track mm/kasan/kasan.c:517 [inline]
kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:609
kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:594
kmem_cache_alloc_trace+0x115/0x2d0 mm/slub.c:2742
kmem_cache_alloc_node_trace include/linux/slab.h:381 [inline]
kmalloc_node include/linux/slab.h:528 [inline]
kzalloc_node include/linux/slab.h:647 [inline]
alloc_disk_node+0x50/0x3c0 block/genhd.c:1294
alloc_disk+0x1b/0x20 block/genhd.c:1286
loop_add+0x37e/0x7b0 drivers/block/loop.c:1850
loop_probe+0x154/0x180 drivers/block/loop.c:1956
kobj_lookup+0x221/0x410 drivers/base/map.c:124
get_gendisk+0x3c/0x2d0 block/genhd.c:716
__blkdev_get+0x356/0xeb0 fs/block_dev.c:1267
blkdev_get+0x2e8/0x920 fs/block_dev.c:1424
blkdev_open+0x1aa/0x250 fs/block_dev.c:1579
do_dentry_open+0x422/0xd20 fs/open.c:772
vfs_open+0x105/0x230 fs/open.c:885
do_last fs/namei.c:3457 [inline]
path_openat+0xbf5/0x2f60 fs/namei.c:3581
do_filp_open+0x1a1/0x280 fs/namei.c:3615
do_sys_open+0x2f0/0x610 fs/open.c:1078
SYSC_open fs/open.c:1096 [inline]
SyS_open+0x2d/0x40 fs/open.c:1091
do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Freed by task 2164:
save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
save_stack mm/kasan/kasan.c:505 [inline]
set_track mm/kasan/kasan.c:517 [inline]
kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:582
slab_free_hook mm/slub.c:1355 [inline]
slab_free_freelist_hook mm/slub.c:1377 [inline]
slab_free mm/slub.c:2958 [inline]
kfree+0xfc/0x310 mm/slub.c:3878
disk_release+0x255/0x330 block/genhd.c:1147
device_release+0x7d/0x220 drivers/base/core.c:247
kobject_cleanup lib/kobject.c:643 [inline]
kobject_release lib/kobject.c:672 [inline]
kref_sub include/linux/kref.h:73 [inline]
kref_put include/linux/kref.h:98 [inline]
kobject_put+0x150/0x260 lib/kobject.c:689
put_disk+0x23/0x30 block/genhd.c:1358
__blkdev_get+0x61a/0xeb0 fs/block_dev.c:1361
blkdev_get+0x2e8/0x920 fs/block_dev.c:1424
blkdev_open+0x1aa/0x250 fs/block_dev.c:1579
do_dentry_open+0x422/0xd20 fs/open.c:772
vfs_open+0x105/0x230 fs/open.c:885
do_last fs/namei.c:3457 [inline]
path_openat+0xbf5/0x2f60 fs/namei.c:3581
do_filp_open+0x1a1/0x280 fs/namei.c:3615
do_sys_open+0x2f0/0x610 fs/open.c:1078
SYSC_open fs/open.c:1096 [inline]
SyS_open+0x2d/0x40 fs/open.c:1091
do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
entry_SYSCALL_64_after_swapgs+0x5d/0xdb
The buggy address belongs to the object at ffff8801cc453b80
which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1376 bytes inside of
2048-byte region [ffff8801cc453b80, ffff8801cc454380)
The buggy address belongs to the page:
page:ffffea0007311400 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000010200(slab|head)
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801cc453f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801cc454000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801cc454080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801cc454100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801cc454180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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