================================================================== BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0x1b1/0x1d0 lib/list_debug.c:62 Read of size 8 at addr ffff8880371dcb38 by task syz.0.5190/18560 CPU: 0 UID: 0 PID: 18560 Comm: syz.0.5190 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: __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+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 __list_del_entry_valid_or_report+0x1b1/0x1d0 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] trace_transfers fs/pnode.c:132 [inline] bulk_make_private+0xd8/0x720 fs/pnode.c:168 umount_tree+0x3fb/0xec0 fs/namespace.c:1786 put_mnt_ns+0x267/0x300 fs/namespace.c:6230 nsproxy_free kernel/nsproxy.c:65 [inline] deactivate_nsproxy kernel/nsproxy.c:79 [inline] put_nsproxy include/linux/nsproxy.h:110 [inline] put_nsproxy include/linux/nsproxy.h:107 [inline] switch_task_namespaces+0x133/0x2c0 kernel/nsproxy.c:252 do_exit+0x824/0x2aa0 kernel/exit.c:970 do_group_exit+0xd5/0x2a0 kernel/exit.c:1112 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x4a0 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+0x67c/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 57a7:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 002b:00000000fcce2242 EFLAGS: 00000207 ORIG_RAX: 0000000000000000 RAX: 0000000000000000 RBX: 0000000041b945c9 RCX: 000000006d3f6aeb RDX: 00000000151ff1ed RSI: 0000000036566808 RDI: 0000000000000000 RBP: 0000000000000000 R08: dbce39d105fdbf88 R09: ae9ea378b9c9fbc7 R10: 33740f3b8630618c R11: 2450ade207355af5 R12: 0a61688f027fb1a4 R13: 339c71c774e61334 R14: 28baed4a0483d193 R15: 7c1f9cf2b758efdc Allocated by task 598: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 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+0x241/0x6e0 mm/slub.c:4837 alloc_vfsmnt+0x23/0x6a0 fs/namespace.c:287 clone_mnt+0x4b/0x930 fs/namespace.c:1246 copy_tree+0x329/0xbf0 fs/namespace.c:2194 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98 copy_namespaces+0x468/0x5e0 kernel/nsproxy.c:195 copy_process+0x3226/0x7a10 kernel/fork.c:2226 kernel_clone+0xfc/0x9a0 kernel/fork.c:2654 __do_sys_clone+0xd9/0x120 kernel/fork.c:2795 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15: 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:253 [inline] __kasan_slab_free+0x5f/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+0x124/0x6a0 mm/slub.c:6254 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622 run_ksoftirqd kernel/softirq.c:1063 [inline] run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 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+0x30/0x50 mm/kasan/common.c:57 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556 __call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3131 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x829/0x2aa0 kernel/exit.c:971 __do_sys_exit kernel/exit.c:1079 [inline] __se_sys_exit kernel/exit.c:1077 [inline] __x64_sys_exit+0x42/0x50 kernel/exit.c:1077 x64_sys_call+0x152e/0x1530 arch/x86/include/generated/asm/syscalls_64.h:61 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Second to last potentially related work creation: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556 task_work_add+0x28b/0x3b0 kernel/task_work.c:70 mntput_no_expire_slowpath+0x3da/0xb00 fs/namespace.c:1379 mntput_no_expire+0x1fd/0x220 fs/namespace.c:1406 mntput fs/namespace.c:1416 [inline] namespace_unlock+0x675/0x920 fs/namespace.c:1713 class_namespace_excl_destructor fs/namespace.c:90 [inline] put_mnt_ns+0x290/0x300 fs/namespace.c:6227 nsproxy_free kernel/nsproxy.c:65 [inline] deactivate_nsproxy kernel/nsproxy.c:79 [inline] put_nsproxy include/linux/nsproxy.h:110 [inline] put_nsproxy include/linux/nsproxy.h:107 [inline] switch_task_namespaces+0x133/0x2c0 kernel/nsproxy.c:252 do_exit+0x824/0x2aa0 kernel/exit.c:970 __do_sys_exit kernel/exit.c:1079 [inline] __se_sys_exit kernel/exit.c:1077 [inline] __x64_sys_exit+0x42/0x50 kernel/exit.c:1077 x64_sys_call+0x152e/0x1530 arch/x86/include/generated/asm/syscalls_64.h:61 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880371dca80 which belongs to the cache mnt_cache of size 352 The buggy address is located 184 bytes inside of freed 352-byte region [ffff8880371dca80, ffff8880371dcbe0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x371dc head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff8880371dc171 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff888140416140 dead000000000100 dead000000000122 raw: 0000000000000000 000001c000120012 00000000f5000000 ffff8880371dc171 head: 00fff00000000040 ffff888140416140 dead000000000100 dead000000000122 head: 0000000000000000 000001c000120012 00000000f5000000 ffff8880371dc171 head: 00fff00000000001 ffffea0000dc7701 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 20577, tgid 20577 (syz-executor), ts 436486765403, free_ts 434326197746 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3255 [inline] allocate_slab mm/slub.c:3444 [inline] new_slab+0xa6/0x6d0 mm/slub.c:3502 refill_objects+0x26b/0x400 mm/slub.c:7134 refill_sheaf mm/slub.c:2804 [inline] alloc_full_sheaf mm/slub.c:2825 [inline] __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4588 alloc_from_pcs mm/slub.c:4681 [inline] slab_alloc_node mm/slub.c:4815 [inline] kmem_cache_alloc_noprof+0x480/0x6e0 mm/slub.c:4837 alloc_vfsmnt+0x23/0x6a0 fs/namespace.c:287 clone_mnt+0x4b/0x930 fs/namespace.c:1246 copy_tree+0x329/0xbf0 fs/namespace.c:2194 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x455/0xab0 kernel/fork.c:3174 __do_sys_unshare kernel/fork.c:3245 [inline] __se_sys_unshare kernel/fork.c:3243 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 page last free pid 5177 tgid 5177 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 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] __do_kmalloc_node mm/slub.c:5218 [inline] __kmalloc_noprof+0x2b9/0x850 mm/slub.c:5231 kmalloc_noprof include/linux/slab.h:966 [inline] tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x276/0x460 security/tomoyo/file.c:827 security_inode_getattr+0x116/0x280 security/security.c:1869 vfs_getattr fs/stat.c:259 [inline] vfs_fstat+0x4b/0xe0 fs/stat.c:281 __do_sys_newfstat+0x8b/0x110 fs/stat.c:551 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880371dca00: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ffff8880371dca80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880371dcb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880371dcb80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880371dcc00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ==================================================================