R13: 00007f860da43fb3 R14: 0000555567f704e8 R15: 00007ffeb2f3ffc0 ---[ end trace fb69054442a5bba2 ]--- ================================================================== BUG: KASAN: use-after-free in fast_dput+0x1e0/0x290 fs/dcache.c:750 Read of size 4 at addr ffff88811c8e2dd0 by task syz-executor/1886 CPU: 1 PID: 1886 Comm: syz-executor Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0x100/0x140 mm/kasan/report.c:452 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 fast_dput+0x1e0/0x290 fs/dcache.c:750 dput+0x21/0x80 fs/dcache.c:870 incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1a1/0x200 fs/incfs/vfs.c:1981 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x44f/0x500 fs/namespace.c:1123 __cleanup_mnt+0x19/0x20 fs/namespace.c:1130 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa7c/0x24e0 kernel/exit.c:879 do_group_exit+0x149/0x310 kernel/exit.c:993 __do_sys_exit_group kernel/exit.c:1004 [inline] __se_sys_exit_group kernel/exit.c:1002 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1002 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f860d9acb19 Code: Unable to access opcode bytes at RIP 0x7f860d9acaef. RSP: 002b:00007ffeb2f3dc38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f860da44013 RCX: 00007f860d9acb19 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007f860da43fb3 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeb2f3eef0 R13: 00007f860da43fb3 R14: 0000555567f704e8 R15: 00007ffeb2f3ffc0 Allocated by task 1984: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] __kasan_slab_alloc+0xb7/0xe0 mm/kasan/common.c:463 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580 slab_alloc_node mm/slub.c:2952 [inline] slab_alloc mm/slub.c:2960 [inline] kmem_cache_alloc+0x15a/0x2d0 mm/slub.c:2965 __d_alloc+0x2d/0x690 fs/dcache.c:1714 d_alloc fs/dcache.c:1793 [inline] d_alloc_parallel+0xe2/0x1390 fs/dcache.c:2549 __lookup_slow+0x14c/0x410 fs/namei.c:1633 lookup_one_len+0x196/0x2d0 fs/namei.c:2706 incfs_lookup_dentry+0x60/0xb0 fs/incfs/data_mgmt.c:210 open_or_create_special_dir+0x4c/0x1e0 fs/incfs/vfs.c:471 incfs_mount_fs+0x434/0x8d0 fs/incfs/vfs.c:1869 legacy_get_tree+0xed/0x190 fs/fs_context.c:593 vfs_get_tree+0x89/0x260 fs/super.c:1583 do_new_mount+0x25a/0xa30 fs/namespace.c:3006 path_mount+0x581/0xca0 fs/namespace.c:3336 do_mount fs/namespace.c:3349 [inline] __do_sys_mount fs/namespace.c:3557 [inline] __se_sys_mount+0x320/0x390 fs/namespace.c:3534 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3534 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 2056: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1600 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626 slab_free mm/slub.c:3208 [inline] kmem_cache_free+0x100/0x2d0 mm/slub.c:3224 __d_free+0x23/0x30 fs/dcache.c:271 rcu_do_batch+0x488/0xaf0 kernel/rcu/tree.c:2494 rcu_core+0x50a/0xca0 kernel/rcu/tree.c:2735 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2748 __do_softirq+0x255/0x563 kernel/softirq.c:309 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2980 [inline] call_rcu+0x11a/0x1090 kernel/rcu/tree.c:3054 dentry_free+0xbd/0x150 fs/dcache.c:-1 __dentry_kill+0x516/0x660 fs/dcache.c:597 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:883 incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1a1/0x200 fs/incfs/vfs.c:1981 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x44f/0x500 fs/namespace.c:1123 __cleanup_mnt+0x19/0x20 fs/namespace.c:1130 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa7c/0x24e0 kernel/exit.c:879 do_group_exit+0x149/0x310 kernel/exit.c:993 __do_sys_exit_group kernel/exit.c:1004 [inline] __se_sys_exit_group kernel/exit.c:1002 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1002 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Second to last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2980 [inline] call_rcu+0x11a/0x1090 kernel/rcu/tree.c:3054 dentry_free+0xbd/0x150 fs/dcache.c:-1 __dentry_kill+0x516/0x660 fs/dcache.c:597 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:883 handle_mounts fs/namei.c:1493 [inline] step_into+0x8e1/0xcd0 fs/namei.c:1790 walk_component+0x263/0x460 fs/namei.c:1966 lookup_last fs/namei.c:2411 [inline] path_lookupat+0x155/0x430 fs/namei.c:2435 filename_lookup+0x1fd/0x660 fs/namei.c:2468 user_path_at_empty+0x43/0x50 fs/namei.c:2790 user_path_at include/linux/namei.h:60 [inline] vfs_statx+0x10a/0x530 fs/stat.c:193 vfs_fstatat fs/stat.c:215 [inline] __do_sys_newfstatat fs/stat.c:383 [inline] __se_sys_newfstatat+0x10e/0x3d0 fs/stat.c:377 __x64_sys_newfstatat+0x9b/0xb0 fs/stat.c:377 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff88811c8e2dd0 which belongs to the cache dentry of size 208 The buggy address is located 0 bytes inside of 208-byte region [ffff88811c8e2dd0, ffff88811c8e2ea0) The buggy address belongs to the page: page:ffffea0004723880 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11c8e2 flags: 0x4000000000000200(slab) raw: 4000000000000200 ffffea0004b0de40 0000000300000003 ffff88810018a300 raw: 0000000000000000 00000000000f000f 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x12cd0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_RECLAIMABLE), pid 282, ts 25569769997, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x176/0x190 mm/page_alloc.c:2462 get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1813 [inline] new_slab+0x84/0x3f0 mm/slub.c:1874 new_slab_objects mm/slub.c:2632 [inline] ___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796 __slab_alloc+0x63/0xa0 mm/slub.c:2836 slab_alloc_node mm/slub.c:2918 [inline] slab_alloc mm/slub.c:2960 [inline] kmem_cache_alloc+0x1a4/0x2d0 mm/slub.c:2965 __d_alloc+0x2d/0x690 fs/dcache.c:1714 d_alloc fs/dcache.c:1793 [inline] d_alloc_parallel+0xe2/0x1390 fs/dcache.c:2549 __lookup_slow+0x14c/0x410 fs/namei.c:1633 lookup_slow+0x57/0x70 fs/namei.c:1665 walk_component+0x326/0x460 fs/namei.c:1960 link_path_walk+0x5d8/0xbd0 fs/namei.c:-1 path_openat+0x290/0x3040 fs/namei.c:3555 do_filp_open+0x1df/0x400 fs/namei.c:3586 do_sys_openat2+0x19f/0x750 fs/open.c:1219 page_owner free stack trace missing Memory state around the buggy address: ffff88811c8e2c80: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ffff88811c8e2d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88811c8e2d80: 00 00 fc fc fc fc fc fc fc fc fa fb fb fb fb fb ^ ffff88811c8e2e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811c8e2e80: fb fb fb fb fc fc fc fc fc fc fc fc fa fb fb fb ================================================================== ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1886 at fs/dcache.c:766 fast_dput+0x207/0x290 fs/dcache.c:766 Modules linked in: CPU: 0 PID: 1886 Comm: syz-executor Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 RIP: 0010:fast_dput+0x207/0x290 fs/dcache.c:766 Code: d9 f2 ff e9 4e fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c a1 fe ff ff 48 89 df e8 83 d9 f2 ff e9 94 fe ff ff e8 b9 4b b8 ff <0f> 0b e9 13 ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c ec fe ff RSP: 0018:ffffc90000fdfba0 EFLAGS: 00010293 RAX: ffffffff81ac6b07 RBX: ffff88811c8e2dd0 RCX: ffff888119f6e400 RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001 RBP: ffffc90000fdfbc8 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520001fbf64 R12: 00000000ffffff80 R13: dffffc0000000000 R14: ffff88811c8e2e28 R15: 1ffff1102391c5c5 FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe54160d000 CR3: 0000000118bc3000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dput+0x21/0x80 fs/dcache.c:870 incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1a1/0x200 fs/incfs/vfs.c:1981 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x44f/0x500 fs/namespace.c:1123 __cleanup_mnt+0x19/0x20 fs/namespace.c:1130 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa7c/0x24e0 kernel/exit.c:879 do_group_exit+0x149/0x310 kernel/exit.c:993 __do_sys_exit_group kernel/exit.c:1004 [inline] __se_sys_exit_group kernel/exit.c:1002 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1002 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f860d9acb19 Code: Unable to access opcode bytes at RIP 0x7f860d9acaef. RSP: 002b:00007ffeb2f3dc38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f860da44013 RCX: 00007f860d9acb19 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007f860da43fb3 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeb2f3eef0 R13: 00007f860da43fb3 R14: 0000555567f704e8 R15: 00007ffeb2f3ffc0 ---[ end trace fb69054442a5bba3 ]--- BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 12e184067 P4D 12e184067 PUD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 1 PID: 1886 Comm: syz-executor Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc90000fdfb40 EFLAGS: 00010246 RAX: 1ffffffff0a52b5f RBX: ffff88812c343aa0 RCX: ffffffff81ac7ea7 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88812c343aa0 RBP: ffffc90000fdfb88 R08: 0000000000000003 R09: 00000000fffffffb R10: dffffc0000000000 R11: ffffed102586875f R12: 1ffff11025868754 R13: dffffc0000000000 R14: ffffffff85295af8 R15: ffff88812c343af8 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000012146d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __dentry_kill+0xca/0x660 fs/dcache.c:571 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:883 incfs_free_mount_info+0x80/0x200 fs/incfs/data_mgmt.c:167 incfs_kill_sb+0x1a1/0x200 fs/incfs/vfs.c:1981 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x44f/0x500 fs/namespace.c:1123 __cleanup_mnt+0x19/0x20 fs/namespace.c:1130 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa7c/0x24e0 kernel/exit.c:879 do_group_exit+0x149/0x310 kernel/exit.c:993 __do_sys_exit_group kernel/exit.c:1004 [inline] __se_sys_exit_group kernel/exit.c:1002 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1002 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f860d9acb19 Code: Unable to access opcode bytes at RIP 0x7f860d9acaef. RSP: 002b:00007ffeb2f3dc38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f860da44013 RCX: 00007f860d9acb19 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007f860da43fb3 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeb2f3eef0 R13: 00007f860da43fb3 R14: 0000555567f704e8 R15: 00007ffeb2f3ffc0 Modules linked in: CR2: 0000000000000000 ---[ end trace fb69054442a5bba4 ]--- RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc90000fdfb40 EFLAGS: 00010246 RAX: 1ffffffff0a52b5f RBX: ffff88812c343aa0 RCX: ffffffff81ac7ea7 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88812c343aa0 RBP: ffffc90000fdfb88 R08: 0000000000000003 R09: 00000000fffffffb R10: dffffc0000000000 R11: ffffed102586875f R12: 1ffff11025868754 R13: dffffc0000000000 R14: ffffffff85295af8 R15: ffff88812c343af8 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000012146d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400