syzkaller0: entered allmulticast mode tipc: Started in network mode tipc: Node identity 6e1cf4139395, cluster identity 4711 tipc: Enabled bearer , priority 0 ================================================================== BUG: KASAN: slab-use-after-free in snapshot_ctr+0x1c20/0x1fd0 drivers/md/dm-snap.c:1282 Read of size 8 at addr ffff888045042f98 by task syz.3.426/7865 CPU: 0 UID: 0 PID: 7865 Comm: syz.3.426 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 snapshot_ctr+0x1c20/0x1fd0 drivers/md/dm-snap.c:1282 dm_table_add_target+0x58b/0xee0 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x3b9/0x7b0 drivers/md/dm-ioctl.c:1645 ctl_ioctl+0x4d2/0xcc0 drivers/md/dm-ioctl.c:2221 dm_ctl_ioctl+0x22/0x30 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f86eeb9f559 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:00007f86efa37028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f86eee25fa0 RCX: 00007f86eeb9f559 RDX: 0000200000000400 RSI: 00000000c138fd09 RDI: 000000000000000a RBP: 00007f86eec36b20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f86eee26038 R14: 00007f86eee25fa0 R15: 00007ffeffc1cd98 Allocated by task 7865: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_node_noprof+0x30c/0x710 mm/slub.c:5582 _kmalloc_node_noprof include/linux/slab.h:1196 [inline] open_table_device drivers/md/dm.c:733 [inline] dm_get_table_device+0x2f8/0x830 drivers/md/dm.c:821 dm_get_device+0x525/0x7e0 drivers/md/dm-table.c:388 snapshot_ctr+0x201/0x1fd0 drivers/md/dm-snap.c:1267 dm_table_add_target+0x58b/0xee0 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x3b9/0x7b0 drivers/md/dm-ioctl.c:1645 ctl_ioctl+0x4d2/0xcc0 drivers/md/dm-ioctl.c:2221 dm_ctl_ioctl+0x22/0x30 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 7865: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6509 [inline] kfree+0x22b/0x6d0 mm/slub.c:6802 close_table_device drivers/md/dm.c:798 [inline] dm_put_table_device+0x2bf/0x380 drivers/md/dm.c:841 upgrade_mode drivers/md/dm-table.c:326 [inline] dm_get_device+0x3f1/0x7e0 drivers/md/dm-table.c:399 snapshot_ctr+0x326/0x1fd0 drivers/md/dm-snap.c:1277 dm_table_add_target+0x58b/0xee0 drivers/md/dm-table.c:749 populate_table drivers/md/dm-ioctl.c:1602 [inline] table_load+0x3b9/0x7b0 drivers/md/dm-ioctl.c:1645 ctl_ioctl+0x4d2/0xcc0 drivers/md/dm-ioctl.c:2221 dm_ctl_ioctl+0x22/0x30 drivers/md/dm-ioctl.c:2243 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888045042f80 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 24 bytes inside of freed 96-byte region [ffff888045042f80, ffff888045042fe0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x45042 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801d038280 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 12, tgid 12 (kworker/u8:0), ts 82369323207 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2e9/0x32e0 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab mm/slub.c:3462 [inline] new_slab+0xa9/0x6e0 mm/slub.c:3513 refill_objects+0xe3/0x410 mm/slub.c:7418 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x677/0x840 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] cfg80211_inform_single_bss_data+0x557/0x1dc0 net/wireless/scan.c:2418 cfg80211_inform_bss_data+0x230/0x3c20 net/wireless/scan.c:3302 cfg80211_inform_bss_frame_data+0x245/0x7c0 net/wireless/scan.c:3394 ieee80211_bss_info_update+0x310/0xab0 net/mac80211/scan.c:230 ieee80211_rx_bss_info net/mac80211/ibss.c:1065 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1546 [inline] ieee80211_ibss_rx_queued_mgmt+0xdff/0x1c70 net/mac80211/ibss.c:1573 ieee80211_iface_process_skb net/mac80211/iface.c:1809 [inline] ieee80211_iface_work+0xa9a/0x1070 net/mac80211/iface.c:1863 cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:564 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 process_scheduled_works kernel/workqueue.c:3479 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560 page last free pid 5918 tgid 5915 ts 82363683869 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 tlb_batch_list_free mm/mmu_gather.c:161 [inline] tlb_finish_mmu+0x27d/0x810 mm/mmu_gather.c:552 exit_mmap+0x454/0xa00 mm/mmap.c:1328 __mmput+0x12a/0x410 kernel/fork.c:1193 mmput+0x62/0x70 kernel/fork.c:1216 exit_mm kernel/exit.c:592 [inline] do_exit+0x83b/0x2a40 kernel/exit.c:974 do_group_exit+0xd5/0x2a0 kernel/exit.c:1130 get_signal+0x1ec2/0x21d0 kernel/signal.c:3112 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x661/0x790 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888045042e80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888045042f00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff888045042f80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff888045043000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888045043080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc ==================================================================