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BUG: KASAN: use-after-free in atomic64_read include/asm-generic/atomic-instrumented.h:836 [inline]
BUG: KASAN: use-after-free in atomic_long_read include/asm-generic/atomic-long.h:28 [inline]
BUG: KASAN: use-after-free in __mutex_unlock_slowpath+0x8e/0x660 kernel/locking/mutex.c:1237
Read of size 8 at addr ffff88803f17e658 by task syz-executor.2/4582

CPU: 1 PID: 4582 Comm: syz-executor.2 Not tainted 5.6.0-rc7-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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:374
 __kasan_report.cold+0x1a/0x32 mm/kasan/report.c:506
 kasan_report+0xe/0x20 mm/kasan/common.c:641
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x128/0x190 mm/kasan/generic.c:192
 atomic64_read include/asm-generic/atomic-instrumented.h:836 [inline]
 atomic_long_read include/asm-generic/atomic-long.h:28 [inline]
 __mutex_unlock_slowpath+0x8e/0x660 kernel/locking/mutex.c:1237
 blkdev_get+0x1d9/0x2b0 fs/block_dev.c:1760
 blkdev_get_by_dev+0x3b/0x70 fs/block_dev.c:1839
 lock_rdev+0x93/0x150 drivers/md/md.c:2496
 md_import_device+0x1fc/0x4a0 drivers/md/md.c:3679
 add_new_disk+0x503/0x18c0 drivers/md/md.c:6657
 md_ioctl+0x41b4/0x5450 drivers/md/md.c:7678
 __blkdev_driver_ioctl block/ioctl.c:321 [inline]
 blkdev_ioctl+0x25b/0x660 block/ioctl.c:717
 block_ioctl+0xe9/0x130 fs/block_dev.c:1983
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c849
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:00007f82b74d3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f82b74d46d4 RCX: 000000000045c849
RDX: 0000000020001200 RSI: 0000000040140921 RDI: 0000000000000006
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000021e R14: 00000000004c4442 R15: 000000000076bf0c

Allocated by task 4582:
 save_stack+0x1b/0x80 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+0xbf/0xd0 mm/kasan/common.c:488
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc mm/slab.c:3320 [inline]
 kmem_cache_alloc+0x11b/0x730 mm/slab.c:3484
 bdev_alloc_inode+0x18/0x40 fs/block_dev.c:772
 alloc_inode+0x61/0x1e0 fs/inode.c:232
 iget5_locked fs/inode.c:1148 [inline]
 iget5_locked+0x57/0xd0 fs/inode.c:1141
 bdget+0x96/0x510 fs/block_dev.c:905
 blkdev_get_by_dev+0x21/0x70 fs/block_dev.c:1835
 lock_rdev+0x93/0x150 drivers/md/md.c:2496
 md_import_device+0x1fc/0x4a0 drivers/md/md.c:3679
 add_new_disk+0x503/0x18c0 drivers/md/md.c:6657
 md_ioctl+0x41b4/0x5450 drivers/md/md.c:7678
 __blkdev_driver_ioctl block/ioctl.c:321 [inline]
 blkdev_ioctl+0x25b/0x660 block/ioctl.c:717
 block_ioctl+0xe9/0x130 fs/block_dev.c:1983
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 16:
 save_stack+0x1b/0x80 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+0xf7/0x140 mm/kasan/common.c:476
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x7f/0x320 mm/slab.c:3694
 i_callback+0x3f/0x70 fs/inode.c:221
 rcu_do_batch kernel/rcu/tree.c:2186 [inline]
 rcu_core+0x5a4/0x12d0 kernel/rcu/tree.c:2410
 __do_softirq+0x26c/0x99d kernel/softirq.c:292

The buggy address belongs to the object at ffff88803f17e640
 which belongs to the cache bdev_cache(49:syz2) of size 1376
The buggy address is located 24 bytes inside of
 1376-byte region [ffff88803f17e640, ffff88803f17eba0)
The buggy address belongs to the page:
page:ffffea0000fc5f80 refcount:1 mapcount:0 mapping:ffff8880946bee00 index:0xffff88803f17effe
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffff888096c49f48 ffff888096c49f48 ffff8880946bee00
raw: ffff88803f17effe ffff88803f17e040 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88803f17e500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88803f17e580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88803f17e600: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                    ^
 ffff88803f17e680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803f17e700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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