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BUG: KASAN: use-after-free in bdev_nr_sectors include/linux/genhd.h:266 [inline]
BUG: KASAN: use-after-free in disk_part_iter_next+0x3a1/0x440 block/genhd.c:206
Read of size 8 at addr ffff888014ecb9a8 by task syz-executor.0/10166

CPU: 0 PID: 10166 Comm: syz-executor.0 Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x9a/0xcc lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230
 __kasan_report mm/kasan/report.c:396 [inline]
 kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
 bdev_nr_sectors include/linux/genhd.h:266 [inline]
 disk_part_iter_next+0x3a1/0x440 block/genhd.c:206
 blk_drop_partitions+0xe0/0x150 block/partitions/core.c:541
 bdev_disk_changed+0x196/0x330 fs/block_dev.c:1229
 __loop_clr_fd+0x6cd/0xea0 drivers/block/loop.c:1268
 __blkdev_put+0x460/0x6c0 fs/block_dev.c:1571
 blkdev_put+0x75/0x480 fs/block_dev.c:1624
 blkdev_close+0x8b/0xd0 fs/block_dev.c:1632
 __fput+0x204/0x870 fs/file_table.c:280
 task_work_run+0xc0/0x160 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x41926b
Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffcd9046b80 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 000000000041926b
RDX: 0000000000570238 RSI: 0000000000000081 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000570238
R13: 00007ffcd9046ca0 R14: 000000000056bf60 R15: 000000000000d576

Allocated by task 10138:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:401 [inline]
 ____kasan_kmalloc.constprop.0+0x82/0xa0 mm/kasan/common.c:429
 kasan_slab_alloc include/linux/kasan.h:209 [inline]
 slab_post_alloc_hook mm/slab.h:512 [inline]
 slab_alloc_node mm/slub.c:2892 [inline]
 slab_alloc mm/slub.c:2900 [inline]
 kmem_cache_alloc+0x1c6/0x440 mm/slub.c:2905
 bdev_alloc_inode+0x13/0x70 fs/block_dev.c:778
 alloc_inode+0x56/0x1e0 fs/inode.c:233
 new_inode_pseudo fs/inode.c:927 [inline]
 new_inode+0x1a/0x2d0 fs/inode.c:956
 bdev_alloc+0x1b/0x2f0 fs/block_dev.c:868
 add_partition+0x175/0x780 block/partitions/core.c:346
 bdev_add_partition+0x93/0xe0 block/partitions/core.c:449
 blkpg_do_ioctl+0x210/0x2c0 block/ioctl.c:43
 blkpg_ioctl block/ioctl.c:60 [inline]
 blkdev_ioctl+0x49e/0x5f0 block/ioctl.c:541
 block_ioctl+0xd4/0x130 fs/block_dev.c:1650
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x11f/0x190 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 12:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:356
 ____kasan_slab_free+0xe1/0x110 mm/kasan/common.c:362
 kasan_slab_free include/linux/kasan.h:192 [inline]
 slab_free_hook mm/slub.c:1547 [inline]
 slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1580
 slab_free mm/slub.c:3143 [inline]
 kmem_cache_free+0x82/0x350 mm/slub.c:3159
 rcu_do_batch kernel/rcu/tree.c:2489 [inline]
 rcu_core+0x5eb/0xf00 kernel/rcu/tree.c:2723
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:343

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xc5/0xf0 mm/kasan/generic.c:344
 __call_rcu kernel/rcu/tree.c:2965 [inline]
 call_rcu+0xbb/0x700 kernel/rcu/tree.c:3038
 disk_part_iter_exit block/genhd.c:235 [inline]
 disk_part_iter_next+0x83/0x440 block/genhd.c:202
 blk_drop_partitions+0xe0/0x150 block/partitions/core.c:541
 bdev_disk_changed+0x196/0x330 fs/block_dev.c:1229
 loop_reread_partitions+0x22/0x40 drivers/block/loop.c:655
 loop_set_status+0x5e8/0xee0 drivers/block/loop.c:1416
 loop_set_status64 drivers/block/loop.c:1536 [inline]
 lo_ioctl+0x24a/0x1690 drivers/block/loop.c:1704
 blkdev_ioctl+0x24c/0x5f0 block/ioctl.c:576
 block_ioctl+0xd4/0x130 fs/block_dev.c:1650
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x11f/0x190 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888014ecb980
 which belongs to the cache bdev_cache of size 2792
The buggy address is located 40 bytes inside of
 2792-byte region [ffff888014ecb980, ffff888014ecc468)
The buggy address belongs to the page:
page:0000000031e76ac0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14ec8
head:0000000031e76ac0 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888140005b40
raw: 0000000000000000 00000000800b000b 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888014ecb880: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
 ffff888014ecb900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888014ecb980: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888014ecba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888014ecba80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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