KASAN: slab-use-after-free Read in change_mnt

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision
420f4853	assessment-security		💥	KASAN: slab-use-after-free Read in change_mnt_propagation	2026/05/14 11:51	2026/05/14 11:51	2026/05/14 11:52	6ccb967e
a11778a1	repro		❓	KASAN: slab-use-after-free Read in change_mnt_propagation	2026/03/06 15:46	2026/03/06 15:46	2026/03/06 15:55	31e9c887
0abb50e4	moderation	Actionable: ✅ Confident: ✅	❓	KASAN: slab-use-after-free Read in change_mnt_propagation	2026/02/24 17:36	2026/02/24 17:36	2026/02/24 17:52	305c0ec5

================================================================== BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0x92/0x190 lib/list_debug.c:62 Read of size 8 at addr ffff888062884b38 by task syz.6.4289/20574 CPU: 0 UID: 0 PID: 20574 Comm: syz.6.4289 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 __list_del_entry_valid_or_report+0x92/0x190 lib/list_debug.c:62 __list_del_entry_valid include/linux/list.h:132 [inline] __list_del_entry include/linux/list.h:223 [inline] list_del_init include/linux/list.h:295 [inline] change_mnt_propagation+0x11c/0x7a0 fs/pnode.c:106 mount_setattr_commit fs/namespace.c:4867 [inline] do_mount_setattr+0xdac/0x1560 fs/namespace.c:4919 __do_sys_mount_setattr fs/namespace.c:5125 [inline] __se_sys_mount_setattr+0x1d7/0x280 fs/namespace.c:5091 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f00a9d9c629 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:00007f00aacd6028 EFLAGS: 00000246 ORIG_RAX: 00000000000001ba RAX: ffffffffffffffda RBX: 00007f00aa015fa0 RCX: 00007f00a9d9c629 RDX: 0000000000000000 RSI: 0000200000000080 RDI: ffffffffffffff9c RBP: 00007f00a9e32b39 R08: 0000000000000020 R09: 0000000000000000 R10: 0000200000001dc0 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f00aa016038 R14: 00007f00aa015fa0 R15: 00007ffcbac744f8 </TASK> Allocated by task 20228: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4501 [inline] slab_alloc_node mm/slub.c:4830 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4837 alloc_vfsmnt+0x23/0x420 fs/namespace.c:287 clone_mnt+0x4b/0x9a0 fs/namespace.c:1246 create_new_namespace fs/namespace.c:3098 [inline] open_new_namespace fs/namespace.c:3168 [inline] vfs_open_tree+0x507/0x1040 fs/namespace.c:3217 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 23: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2687 [inline] slab_free mm/slub.c:6124 [inline] kmem_cache_free+0x187/0x630 mm/slub.c:6254 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1063 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3131 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3251 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Second to last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 task_work_add+0xb6/0x440 kernel/task_work.c:70 mntput_no_expire_slowpath+0x70c/0xbd0 fs/namespace.c:1379 create_new_namespace fs/namespace.c:3162 [inline] open_new_namespace fs/namespace.c:3168 [inline] vfs_open_tree+0xe17/0x1040 fs/namespace.c:3217 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888062884a80 which belongs to the cache mnt_cache of size 352 The buggy address is located 184 bytes inside of freed 352-byte region [ffff888062884a80, ffff888062884be0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880628841c0 pfn:0x62884 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff888062884171 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801babd8c0 ffffea0001e94410 ffffea0000d6f510 raw: ffff8880628841c0 000001c00012000e 00000000f5000000 ffff888062884171 head: 00fff00000000240 ffff88801babd8c0 ffffea0001e94410 ffffea0000d6f510 head: ffff8880628841c0 000001c00012000e 00000000f5000000 ffff888062884171 head: 00fff00000000001 ffffea00018a2101 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 19052, tgid 19049 (syz.5.3934), ts 707415879604, free_ts 695807241879 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3255 [inline] allocate_slab+0x77/0x660 mm/slub.c:3444 new_slab mm/slub.c:3502 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7134 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578 alloc_from_pcs mm/slub.c:4681 [inline] slab_alloc_node mm/slub.c:4815 [inline] kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4837 alloc_vfsmnt+0x23/0x420 fs/namespace.c:287 clone_mnt+0x4b/0x9a0 fs/namespace.c:1246 copy_tree+0x3d4/0x930 fs/namespace.c:2194 copy_mnt_ns+0x24d/0x990 fs/namespace.c:4246 create_new_namespaces+0xcf/0x6a0 kernel/nsproxy.c:98 copy_namespaces+0x438/0x4b0 kernel/nsproxy.c:195 copy_process+0x18e2/0x3cf0 kernel/fork.c:2226 kernel_clone+0x248/0x8e0 kernel/fork.c:2654 __do_sys_clone kernel/fork.c:2795 [inline] __se_sys_clone kernel/fork.c:2779 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2779 page last free pid 18910 tgid 18910 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978 __folio_put+0x414/0x4f0 mm/swap.c:112 pipe_buf_release include/linux/pipe_fs_i.h:273 [inline] free_pipe_info+0x1f5/0x3a0 fs/pipe.c:855 put_pipe_info fs/pipe.c:721 [inline] pipe_release+0x242/0x330 fs/pipe.c:744 __fput+0x44f/0xa70 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888062884a00: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ffff888062884a80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888062884b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888062884b80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888062884c00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ==================================================================

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/02/20 06:30	upstream	8bf22c33e7a1	17d780d6	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-kasan-gce-root	KASAN: slab-use-after-free Read in change_mnt_propagation

Crashes (1):

Assets (help?)