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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+0x49d/0x530 block/genhd.c:206
Read of size 8 at addr ffff888046d86428 by task syz-executor.0/10087

CPU: 3 PID: 10087 Comm: syz-executor.0 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2c6 mm/kasan/report.c:232
 __kasan_report mm/kasan/report.c:399 [inline]
 kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
 bdev_nr_sectors include/linux/genhd.h:266 [inline]
 disk_part_iter_next+0x49d/0x530 block/genhd.c:206
 blk_drop_partitions+0x10a/0x180 block/partitions/core.c:541
 bdev_disk_changed+0x238/0x430 fs/block_dev.c:1246
 __loop_clr_fd+0xc7c/0xff0 drivers/block/loop.c:1271
 loop_clr_fd drivers/block/loop.c:1336 [inline]
 lo_ioctl+0x3b9/0x1620 drivers/block/loop.c:1694
 blkdev_ioctl+0x2a1/0x6d0 block/ioctl.c:583
 block_ioctl+0xf9/0x140 fs/block_dev.c:1667
 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+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x466217
Code: 3c 1c 48 f7 d8 49 39 c4 72 b8 e8 a4 48 02 00 85 c0 78 bd 48 83 c4 08 4c 89 e0 5b 41 5c c3 0f 1f 44 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb06f327ef8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb06f327f40 RCX: 0000000000466217
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004
RBP: 00007fb06f3286bc R08: 0000000000000001 R09: 00007fb06f327d90
R10: 00007fb06f327c47 R11: 0000000000000246 R12: 0000000000000008
R13: 0000000000000000 R14: 0000000000000000 R15: 00007fb06f327f80

Allocated by task 10012:
 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:427 [inline]
 __kasan_slab_alloc+0x73/0x90 mm/kasan/common.c:460
 kasan_slab_alloc include/linux/kasan.h:223 [inline]
 slab_post_alloc_hook mm/slab.h:516 [inline]
 slab_alloc mm/slab.c:3325 [inline]
 kmem_cache_alloc+0x1c8/0x500 mm/slab.c:3502
 bdev_alloc_inode+0x18/0x80 fs/block_dev.c:795
 alloc_inode+0x61/0x230 fs/inode.c:234
 new_inode_pseudo fs/inode.c:928 [inline]
 new_inode+0x27/0x2f0 fs/inode.c:957
 bdev_alloc+0x20/0x2f0 fs/block_dev.c:885
 add_partition+0x1ab/0x880 block/partitions/core.c:346
 bdev_add_partition+0xb6/0x130 block/partitions/core.c:449
 blkpg_do_ioctl+0x2d0/0x340 block/ioctl.c:43
 blkpg_ioctl block/ioctl.c:60 [inline]
 blkdev_ioctl+0x577/0x6d0 block/ioctl.c:548
 block_ioctl+0xf9/0x140 fs/block_dev.c:1667
 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+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 5021:
 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:357
 ____kasan_slab_free mm/kasan/common.c:360 [inline]
 ____kasan_slab_free mm/kasan/common.c:325 [inline]
 __kasan_slab_free+0xc7/0x100 mm/kasan/common.c:367
 kasan_slab_free include/linux/kasan.h:199 [inline]
 __cache_free mm/slab.c:3440 [inline]
 kmem_cache_free+0x6d/0x1f0 mm/slab.c:3733
 i_callback+0x3f/0x70 fs/inode.c:223
 rcu_do_batch kernel/rcu/tree.c:2559 [inline]
 rcu_core+0x74a/0x12f0 kernel/rcu/tree.c:2794
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xa4/0xd0 mm/kasan/generic.c:345
 __call_rcu kernel/rcu/tree.c:3039 [inline]
 call_rcu+0xb1/0x740 kernel/rcu/tree.c:3114
 destroy_inode+0x129/0x1b0 fs/inode.c:289
 iput_final fs/inode.c:1654 [inline]
 iput.part.0+0x57e/0x810 fs/inode.c:1680
 iput+0x58/0x70 fs/inode.c:1670
 disk_part_iter_exit block/genhd.c:235 [inline]
 disk_part_iter_next+0x9a/0x530 block/genhd.c:202
 blk_drop_partitions+0x10a/0x180 block/partitions/core.c:541
 bdev_disk_changed+0x238/0x430 fs/block_dev.c:1246
 loop_reread_partitions+0x29/0x50 drivers/block/loop.c:655
 loop_set_status+0x704/0x1050 drivers/block/loop.c:1418
 loop_set_status64 drivers/block/loop.c:1538 [inline]
 lo_ioctl+0x4ca/0x1620 drivers/block/loop.c:1706
 blkdev_ioctl+0x2a1/0x6d0 block/ioctl.c:583
 block_ioctl+0xf9/0x140 fs/block_dev.c:1667
 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+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888046d86400
 which belongs to the cache bdev_cache of size 2792
The buggy address is located 40 bytes inside of
 2792-byte region [ffff888046d86400, ffff888046d86ee8)
The buggy address belongs to the page:
page:ffffea00011b6180 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888046d86fff pfn:0x46d86
flags: 0x4fff00000000200(slab)
raw: 04fff00000000200 ffffea00010dcf88 ffffea00011b71c8 ffff888040247200
raw: ffff888046d86fff ffff888046d86400 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888046d86300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888046d86380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888046d86400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888046d86480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888046d86500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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