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BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:938 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0x1033/0x13c0 kernel/locking/mutex.c:1103
Read of size 8 at addr ffff888096b99130 by task syz-executor.1/6836

CPU: 0 PID: 6836 Comm: syz-executor.1 Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:641
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 __mutex_lock_common kernel/locking/mutex.c:938 [inline]
 __mutex_lock+0x1033/0x13c0 kernel/locking/mutex.c:1103
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
 blkdev_get+0xfc/0x2c0 fs/block_dev.c:1742
 blkdev_get_by_dev+0x42/0x80 fs/block_dev.c:1839
 lock_rdev+0xa0/0x160 drivers/md/md.c:2496
 md_import_device+0x221/0x520 drivers/md/md.c:3679
 add_new_disk+0x53f/0x1a20 drivers/md/md.c:6657
 md_ioctl+0x4a19/0x5ea0 drivers/md/md.c:7678
 __blkdev_driver_ioctl block/ioctl.c:321 [inline]
 blkdev_ioctl+0x263/0x670 block/ioctl.c:717
 block_ioctl+0xee/0x130 fs/block_dev.c:1983
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x123/0x180 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c429
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f709d676c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f709d6776d4 RCX: 000000000045c429
RDX: 0000000020001200 RSI: 0000000040140921 RDI: 0000000000000004
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000021e R14: 00000000004c4005 R15: 000000000076bf2c

Allocated by task 6836:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:523
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc mm/slab.c:3320 [inline]
 kmem_cache_alloc+0x121/0x710 mm/slab.c:3484
 bdev_alloc_inode+0x1c/0x50 fs/block_dev.c:772
 alloc_inode+0x68/0x1e0 fs/inode.c:231
 iget5_locked fs/inode.c:1147 [inline]
 iget5_locked+0x63/0xe0 fs/inode.c:1140
 bdget+0x97/0x550 fs/block_dev.c:905
 blkdev_get_by_dev+0x27/0x80 fs/block_dev.c:1835
 lock_rdev+0xa0/0x160 drivers/md/md.c:2496
 md_import_device+0x221/0x520 drivers/md/md.c:3679
 add_new_disk+0x53f/0x1a20 drivers/md/md.c:6657
 md_ioctl+0x4a19/0x5ea0 drivers/md/md.c:7678
 __blkdev_driver_ioctl block/ioctl.c:321 [inline]
 blkdev_ioctl+0x263/0x670 block/ioctl.c:717
 block_ioctl+0xee/0x130 fs/block_dev.c:1983
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x123/0x180 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x86/0x320 mm/slab.c:3694
 bdev_free_inode+0x20/0x30 fs/block_dev.c:780
 i_callback+0x44/0x80 fs/inode.c:220
 rcu_do_batch kernel/rcu/tree.c:2186 [inline]
 rcu_core+0x5e1/0x1390 kernel/rcu/tree.c:2410
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2419
 __do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff888096b990c0
 which belongs to the cache bdev_cache(49:syz1) of size 1368
The buggy address is located 112 bytes inside of
 1368-byte region [ffff888096b990c0, ffff888096b99618)
The buggy address belongs to the page:
page:ffffea00025ae640 refcount:1 mapcount:0 mapping:ffff8880a2c708c0 index:0xffff888096b99ffe
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00025a50c8 ffffea0002486448 ffff8880a2c708c0
raw: ffff888096b99ffe ffff888096b990c0 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888096b99000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888096b99080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff888096b99100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888096b99180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888096b99200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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