================================================================== BUG: KASAN: slab-use-after-free in snapshot_ctr+0x5cc/0x1340 drivers/md/dm-snap.c:1288 Read of size 8 at addr ffff888024e3e418 by task syz.2.134/6479 CPU: 0 PID: 6479 Comm: syz.2.134 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xa8/0x210 mm/kasan/report.c:468 kasan_report+0x117/0x150 mm/kasan/report.c:581 snapshot_ctr+0x5cc/0x1340 drivers/md/dm-snap.c:1288 dm_table_add_target+0x575/0xbc0 drivers/md/dm-table.c:732 populate_table drivers/md/dm-ioctl.c:1502 [inline] table_load+0x2eb/0x7e0 drivers/md/dm-ioctl.c:1544 ctl_ioctl drivers/md/dm-ioctl.c:2115 [inline] dm_ctl_ioctl+0x975/0xd00 drivers/md/dm-ioctl.c:2137 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7efeba19f559 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:00007efebb101028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007efeba425fa0 RCX: 00007efeba19f559 RDX: 0000200000000500 RSI: 00000000c138fd09 RDI: 0000000000000003 RBP: 00007efeba236b20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007efeba426038 R14: 00007efeba425fa0 R15: 00007ffe69717048 Allocated by task 6479: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384 kmalloc_node include/linux/slab.h:616 [inline] open_table_device drivers/md/dm.c:731 [inline] dm_get_table_device+0x248/0x670 drivers/md/dm.c:800 dm_get_device+0x4b9/0x9e0 drivers/md/dm-table.c:378 snapshot_ctr+0x2b3/0x1340 drivers/md/dm-snap.c:1273 dm_table_add_target+0x575/0xbc0 drivers/md/dm-table.c:732 populate_table drivers/md/dm-ioctl.c:1502 [inline] table_load+0x2eb/0x7e0 drivers/md/dm-ioctl.c:1544 ctl_ioctl drivers/md/dm-ioctl.c:2115 [inline] dm_ctl_ioctl+0x975/0xd00 drivers/md/dm-ioctl.c:2137 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 6479: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1833 [inline] slab_free_freelist_hook+0x154/0x240 mm/slub.c:1859 slab_free mm/slub.c:3853 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3866 close_table_device drivers/md/dm.c:777 [inline] dm_put_table_device+0x20e/0x240 drivers/md/dm.c:820 upgrade_mode drivers/md/dm-table.c:327 [inline] dm_get_device+0x7ca/0x9e0 drivers/md/dm-table.c:389 snapshot_ctr+0x472/0x1340 drivers/md/dm-snap.c:1283 dm_table_add_target+0x575/0xbc0 drivers/md/dm-table.c:732 populate_table drivers/md/dm-ioctl.c:1502 [inline] table_load+0x2eb/0x7e0 drivers/md/dm-ioctl.c:1544 ctl_ioctl drivers/md/dm-ioctl.c:2115 [inline] dm_ctl_ioctl+0x975/0xd00 drivers/md/dm-ioctl.c:2137 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff888024e3e400 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 24 bytes inside of freed 64-byte region [ffff888024e3e400, ffff888024e3e440) The buggy address belongs to the physical page: page:ffffea0000938f80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24e3e flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000800 ffff888018c41640 ffffea000098f680 dead000000000002 raw: 0000000000000000 0000000000200020 00000001ffffffff 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 60, tgid 60 (kworker/u4:4), ts 7109153935, free_ts 7099545050 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582 prep_new_page mm/page_alloc.c:1589 [inline] get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501 alloc_slab_page+0x5d/0x180 mm/slub.c:1903 allocate_slab mm/slub.c:2050 [inline] new_slab+0x87/0x2d0 mm/slub.c:2103 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3275 __slab_alloc mm/slub.c:3361 [inline] __slab_alloc_node mm/slub.c:3414 [inline] slab_alloc_node mm/slub.c:3508 [inline] __kmem_cache_alloc_node+0x122/0x260 mm/slub.c:3557 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [inline] percpu_ref_init+0xc3/0x340 lib/percpu-refcount.c:76 blk_alloc_queue+0x369/0x4c0 block/blk-core.c:440 blk_mq_init_queue_data block/blk-mq.c:4267 [inline] blk_mq_init_queue+0x3b/0xe0 block/blk-mq.c:4281 scsi_alloc_sdev+0x70d/0xab0 drivers/scsi/scsi_scan.c:335 scsi_probe_and_add_lun+0x1bb/0x4730 drivers/scsi/scsi_scan.c:1186 __scsi_scan_target+0x1ee/0x1090 drivers/scsi/scsi_scan.c:1724 scsi_scan_channel drivers/scsi/scsi_scan.c:1812 [inline] scsi_scan_host_selected+0x401/0x7f0 drivers/scsi/scsi_scan.c:1841 do_scsi_scan_host drivers/scsi/scsi_scan.c:1980 [inline] do_scan_async+0x112/0x7d0 drivers/scsi/scsi_scan.c:1990 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1182 [inline] free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2505 release_pages+0x208a/0x2300 mm/swap.c:1022 tlb_batch_pages_flush mm/mmu_gather.c:99 [inline] tlb_flush_mmu_free mm/mmu_gather.c:294 [inline] tlb_flush_mmu+0x379/0x510 mm/mmu_gather.c:301 tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:425 exit_mmap+0x428/0xb90 mm/mmap.c:3323 __mmput+0x118/0x3a0 kernel/fork.c:1362 free_bprm+0x144/0x390 fs/exec.c:1533 kernel_execve+0x3e9/0x980 fs/exec.c:2079 call_usermodehelper_exec_async+0x20b/0x350 kernel/umh.c:110 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Memory state around the buggy address: ffff888024e3e300: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc ffff888024e3e380: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc >ffff888024e3e400: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff888024e3e480: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888024e3e500: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================