================================================================== BUG: KASAN: slab-use-after-free in snapshot_ctr+0x5cb/0x1340 drivers/md/dm-snap.c:1282 Read of size 8 at addr ffff88802a930498 by task syz.5.472/8373 CPU: 1 UID: 0 PID: 8373 Comm: syz.5.472 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 snapshot_ctr+0x5cb/0x1340 drivers/md/dm-snap.c:1282 dm_table_add_target+0x58d/0xc70 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x325/0x8a0 drivers/md/dm-ioctl.c:1645 ctl_ioctl drivers/md/dm-ioctl.c:2221 [inline] dm_ctl_ioctl+0x9ec/0xe10 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f04dd59f559 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:00007f04de4cf028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f04dd825fa0 RCX: 00007f04dd59f559 RDX: 0000200000000440 RSI: 00000000c138fd09 RDI: 0000000000000003 RBP: 00007f04dd636b20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f04dd826038 R14: 00007f04dd825fa0 R15: 00007ffd37149f28 Allocated by task 8373: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_node_noprof+0x3cc/0x620 mm/slub.c:5699 _kmalloc_node_noprof include/linux/slab.h:1196 [inline] open_table_device drivers/md/dm.c:733 [inline] dm_get_table_device+0x23e/0x730 drivers/md/dm.c:821 dm_get_device+0x327/0x760 drivers/md/dm-table.c:388 snapshot_ctr+0x2b2/0x1340 drivers/md/dm-snap.c:1267 dm_table_add_target+0x58d/0xc70 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x325/0x8a0 drivers/md/dm-ioctl.c:1645 ctl_ioctl drivers/md/dm-ioctl.c:2221 [inline] dm_ctl_ioctl+0x9ec/0xe10 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 8373: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2780 [inline] slab_free mm/slub.c:6630 [inline] kfree+0x1c5/0x650 mm/slub.c:6923 close_table_device drivers/md/dm.c:798 [inline] dm_put_table_device+0x255/0x2a0 drivers/md/dm.c:841 upgrade_mode drivers/md/dm-table.c:326 [inline] dm_get_device+0x56f/0x760 drivers/md/dm-table.c:399 snapshot_ctr+0x471/0x1340 drivers/md/dm-snap.c:1277 dm_table_add_target+0x58d/0xc70 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x325/0x8a0 drivers/md/dm-ioctl.c:1645 ctl_ioctl drivers/md/dm-ioctl.c:2221 [inline] dm_ctl_ioctl+0x9ec/0xe10 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802a930480 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 24 bytes inside of freed 96-byte region [ffff88802a930480, ffff88802a9304e0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a930 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801c041280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000200020 00000000f5000000 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 83, tgid 83 (kworker/u8:5), ts 6874097602 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1854 prep_new_page mm/page_alloc.c:1862 [inline] get_page_from_freelist+0x220f/0x2280 mm/page_alloc.c:3933 __alloc_frozen_pages_noprof+0x1fc/0x400 mm/page_alloc.c:5429 alloc_slab_page mm/slub.c:3384 [inline] allocate_slab+0x7d/0x5e0 mm/slub.c:3499 new_slab mm/slub.c:3550 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7539 refill_sheaf mm/slub.c:2917 [inline] __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4811 alloc_from_pcs mm/slub.c:4887 [inline] slab_alloc_node mm/slub.c:5021 [inline] __do_kmalloc_node mm/slub.c:5530 [inline] __kmalloc_noprof+0x476/0x710 mm/slub.c:5556 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] lsm_blob_alloc security/security.c:219 [inline] lsm_task_alloc security/security.c:271 [inline] security_task_alloc+0x4d/0x330 security/security.c:2806 copy_process+0x1c75/0x44b0 kernel/fork.c:2299 kernel_clone+0x2d7/0x940 kernel/fork.c:2783 user_mode_thread+0x115/0x180 kernel/fork.c:2860 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:169 process_one_work kernel/workqueue.c:3495 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 page_owner free stack trace missing Memory state around the buggy address: ffff88802a930380: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ffff88802a930400: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc >ffff88802a930480: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff88802a930500: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88802a930580: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ==================================================================