==================================================================
BUG: KASAN: slab-use-after-free in snapshot_ctr+0x586/0x1350 drivers/md/dm-snap.c:1288
Read of size 8 at addr ffff888117f32598 by task syz.1.295/1248

CPU: 0 UID: 0 PID: 1248 Comm: syz.1.295 Not tainted syzkaller #0 790d506eeb1243e613a7e15525cb861d28cb7486
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 print_address_description+0x71/0x210 mm/kasan/report.c:377
 print_report+0x4a/0x70 mm/kasan/report.c:481
 kasan_report+0x162/0x1a0 mm/kasan/report.c:594
 __asan_report_load8_noabort+0x18/0x20 mm/kasan/report_generic.c:381
 snapshot_ctr+0x586/0x1350 drivers/md/dm-snap.c:1288
 dm_table_add_target+0x59f/0xcb0 drivers/md/dm-table.c:760
 populate_table drivers/md/dm-ioctl.c:1494 [inline]
 table_load+0x2eb/0x7d0 drivers/md/dm-ioctl.c:1536
 ctl_ioctl drivers/md/dm-ioctl.c:2104 [inline]
 dm_ctl_ioctl+0x8f3/0xde0 drivers/md/dm-ioctl.c:2126
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0x126/0x1b0 fs/ioctl.c:892
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:892
 x64_sys_call+0x1878/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f4b8599f559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4b868c6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4b85c25fa0 RCX: 00007f4b8599f559
RDX: 0000200000000380 RSI: 00000000c138fd09 RDI: 0000000000000003
RBP: 00007f4b85a36b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4b85c26038 R14: 00007f4b85c25fa0 R15: 00007ffc6782a468
 </TASK>

Allocated by task 1248:
 kasan_save_stack mm/kasan/common.c:49 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
 kasan_save_alloc_info+0x3a/0x50 mm/kasan/generic.c:565
 poison_kmalloc_redzone mm/kasan/common.c:379 [inline]
 __kasan_kmalloc+0x96/0xb0 mm/kasan/common.c:396
 kasan_kmalloc include/linux/kasan.h:261 [inline]
 __kmalloc_cache_node_noprof+0x225/0x430 mm/slub.c:4438
 kmalloc_node_noprof include/linux/slab.h:1004 [inline]
 open_table_device drivers/md/dm.c:758 [inline]
 dm_get_table_device+0x1e3/0x6c0 drivers/md/dm.c:837
 dm_get_device+0x32b/0x7f0 drivers/md/dm-table.c:394
 snapshot_ctr+0x292/0x1350 drivers/md/dm-snap.c:1273
 dm_table_add_target+0x59f/0xcb0 drivers/md/dm-table.c:760
 populate_table drivers/md/dm-ioctl.c:1494 [inline]
 table_load+0x2eb/0x7d0 drivers/md/dm-ioctl.c:1536
 ctl_ioctl drivers/md/dm-ioctl.c:2104 [inline]
 dm_ctl_ioctl+0x8f3/0xde0 drivers/md/dm-ioctl.c:2126
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0x126/0x1b0 fs/ioctl.c:892
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:892
 x64_sys_call+0x1878/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Freed by task 1248:
 kasan_save_stack mm/kasan/common.c:49 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
 kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:249 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:266
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2445 [inline]
 slab_free mm/slub.c:4714 [inline]
 kfree+0x158/0x440 mm/slub.c:4875
 close_table_device drivers/md/dm.c:814 [inline]
 dm_put_table_device+0x298/0x2e0 drivers/md/dm.c:857
 upgrade_mode drivers/md/dm-table.c:328 [inline]
 dm_get_device+0x571/0x7f0 drivers/md/dm-table.c:405
 snapshot_ctr+0x435/0x1350 drivers/md/dm-snap.c:1283
 dm_table_add_target+0x59f/0xcb0 drivers/md/dm-table.c:760
 populate_table drivers/md/dm-ioctl.c:1494 [inline]
 table_load+0x2eb/0x7d0 drivers/md/dm-ioctl.c:1536
 ctl_ioctl drivers/md/dm-ioctl.c:2104 [inline]
 dm_ctl_ioctl+0x8f3/0xde0 drivers/md/dm-ioctl.c:2126
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0x126/0x1b0 fs/ioctl.c:892
 __x64_sys_ioctl+0x7f/0xa0 fs/ioctl.c:892
 x64_sys_call+0x1878/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

The buggy address belongs to the object at ffff888117f32580
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 24 bytes inside of
 freed 96-byte region [ffff888117f32580, ffff888117f325e0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117f32
anon flags: 0x4000000000000000(zone=1)
page_type: f5(slab)
raw: 4000000000000000 ffff888100041280 ffffea00045bdc80 dead000000000005
raw: 0000000000000000 0000000080200020 00000001f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x152cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 538, tgid 537 (syz.1.67), ts 36075456356, free_ts 35659314425
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook+0x37d/0x3b0 mm/page_alloc.c:1864
 prep_new_page+0x2d/0x180 mm/page_alloc.c:1872
 get_page_from_freelist+0x4aea/0x4ba0 mm/page_alloc.c:3949
 __alloc_pages_noprof+0x35a/0x7e0 mm/page_alloc.c:5316
 alloc_slab_page+0x6b/0x1e0 mm/slub.c:-1
 allocate_slab+0x69/0x430 mm/slub.c:2687
 new_slab mm/slub.c:2741 [inline]
 ___slab_alloc+0x591/0x8c0 mm/slub.c:3934
 __slab_alloc mm/slub.c:4025 [inline]
 __slab_alloc_node mm/slub.c:4078 [inline]
 slab_alloc_node mm/slub.c:4239 [inline]
 __kmalloc_cache_node_noprof+0x2ae/0x430 mm/slub.c:4434
 kmalloc_node_noprof include/linux/slab.h:1004 [inline]
 __get_vm_area_node+0x150/0x390 mm/vmalloc.c:3148
 __vmalloc_node_range_noprof+0x340/0x1300 mm/vmalloc.c:3838
 __vmalloc_node_noprof mm/vmalloc.c:3949 [inline]
 __vmalloc_noprof+0x104/0x1d0 mm/vmalloc.c:3963
 __vmalloc_array_noprof mm/util.c:800 [inline]
 __vcalloc_noprof+0x3a/0x50 mm/util.c:823
 kvm_alloc_memslot_metadata arch/x86/kvm/x86.c:13087 [inline]
 kvm_arch_prepare_memory_region+0x2be/0xf80 arch/x86/kvm/x86.c:13161
 kvm_prepare_memory_region virt/kvm/kvm_main.c:1689 [inline]
 kvm_set_memslot+0x59a/0x13a0 virt/kvm/kvm_main.c:1919
 __kvm_set_memory_region+0x7f7/0xb40 virt/kvm/kvm_main.c:2098
 kvm_set_memory_region+0x2f/0x50 virt/kvm/kvm_main.c:2119
page last free pid 294 tgid 294 stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page+0xb99/0xf50 mm/page_alloc.c:2877
 __free_pages+0x6b/0x3b0 mm/page_alloc.c:5403
 __free_slab+0xb2/0x110 mm/slub.c:2758
 free_slab+0x18/0xe0 mm/slub.c:2781
 discard_slab mm/slub.c:2787 [inline]
 __put_partials+0x115/0x150 mm/slub.c:3256
 put_cpu_partial+0x91/0xc0 mm/slub.c:3331
 __slab_free+0x1cf/0x2a0 mm/slub.c:4584
 do_slab_free mm/slub.c:4666 [inline]
 ___cache_free+0xc9/0xe0 mm/slub.c:4781
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0xb5/0x130 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x180 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x28/0x90 mm/kasan/common.c:331
 kasan_slab_alloc include/linux/kasan.h:251 [inline]
 slab_post_alloc_hook mm/slub.c:4202 [inline]
 slab_alloc_node mm/slub.c:4251 [inline]
 kmem_cache_alloc_noprof+0x1bf/0x410 mm/slub.c:4260
 getname_flags+0xcc/0x6b0 fs/namei.c:139
 user_path_at+0x2b/0x60 fs/namei.c:3023
 ksys_umount fs/namespace.c:2050 [inline]
 __do_sys_umount fs/namespace.c:2058 [inline]
 __se_sys_umount fs/namespace.c:2056 [inline]
 __x64_sys_umount+0xfa/0x180 fs/namespace.c:2056
 x64_sys_call+0x2ab8/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:167

Memory state around the buggy address:
 ffff888117f32480: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
 ffff888117f32500: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff888117f32580: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                            ^
 ffff888117f32600: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888117f32680: 00 00 00 00 00 00 00 00 03 fc fc fc fc fc fc fc
==================================================================
device-mapper: table: 252:1: device 1:2 not in table devices list
device-mapper: table: 252:1: snapshot-merge: COW device cannot be the same as origin device (-EINVAL)
device-mapper: ioctl: error adding target to table
device-mapper: table: 252:1: dm_table_destroy: dm_put_device call missing for 1:2