RBP: 0000000000000009 R08: 00007ffd508c7c37 R09: 00007ffd508cb150 R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffd508cb150 R13: 00007ff85bad7d7d R14: 000055558128f4a8 R15: 00007ffd508cc220 ---[ end trace 50a1f69a7186f86f ]--- ================================================================== BUG: KASAN: use-after-free in fast_dput+0x1e9/0x290 fs/dcache.c:750 Read of size 4 at addr ffff8881101c3bb0 by task syz-executor/399 CPU: 0 PID: 399 Comm: syz-executor Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x169/0x1d8 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+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 fast_dput+0x1e9/0x290 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+0x1aa/0x210 fs/incfs/vfs.c:1979 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x446/0x500 fs/namespace.c:1114 __cleanup_mnt+0x19/0x20 fs/namespace.c:1121 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa4f/0x2480 kernel/exit.c:872 do_group_exit+0x141/0x310 kernel/exit.c:986 __do_sys_exit_group kernel/exit.c:997 [inline] __se_sys_exit_group kernel/exit.c:995 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:995 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7ff85ba556c9 Code: Unable to access opcode bytes at RIP 0x7ff85ba5569f. RSP: 002b:00007ffd508c9e98 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ff85bad7ddd RCX: 00007ff85ba556c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 00007ffd508c7c37 R09: 00007ffd508cb150 R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffd508cb150 R13: 00007ff85bad7d7d R14: 000055558128f4a8 R15: 00007ffd508cc220 Allocated by task 450: 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+0xbd/0xf0 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+0x165/0x2e0 mm/slub.c:2965 __d_alloc+0x2d/0x6a0 fs/dcache.c:1714 d_alloc fs/dcache.c:1793 [inline] d_alloc_parallel+0xd6/0x1320 fs/dcache.c:2547 __lookup_slow+0x13e/0x3e0 fs/namei.c:1625 lookup_one_len+0x18e/0x2c0 fs/namei.c:2656 incfs_lookup_dentry+0x60/0xb0 fs/incfs/data_mgmt.c:210 open_or_create_special_dir+0x4f/0x1d0 fs/incfs/vfs.c:469 incfs_mount_fs+0x434/0x8c0 fs/incfs/vfs.c:1867 legacy_get_tree+0xed/0x190 fs/fs_context.c:593 vfs_get_tree+0x89/0x260 fs/super.c:1572 do_new_mount+0x25a/0xa20 fs/namespace.c:2997 path_mount+0x572/0xc80 fs/namespace.c:3327 do_mount fs/namespace.c:3340 [inline] __do_sys_mount fs/namespace.c:3548 [inline] __se_sys_mount+0x318/0x380 fs/namespace.c:3525 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3525 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 501: 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+0x4df/0xa80 kernel/rcu/tree.c:2494 rcu_core+0x55f/0xd60 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+0x10e/0x1050 kernel/rcu/tree.c:3054 dentry_free+0xbd/0x150 fs/dcache.c:-1 __dentry_kill+0x50a/0x650 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+0x1aa/0x210 fs/incfs/vfs.c:1979 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x446/0x500 fs/namespace.c:1114 __cleanup_mnt+0x19/0x20 fs/namespace.c:1121 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa4f/0x2480 kernel/exit.c:872 do_group_exit+0x141/0x310 kernel/exit.c:986 __do_sys_exit_group kernel/exit.c:997 [inline] __se_sys_exit_group kernel/exit.c:995 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:995 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+0x10e/0x1050 kernel/rcu/tree.c:3054 dentry_free+0xbd/0x150 fs/dcache.c:-1 __dentry_kill+0x50a/0x650 fs/dcache.c:597 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:883 handle_mounts fs/namei.c:1485 [inline] step_into+0x8f0/0xcf0 fs/namei.c:1782 walk_component+0x26a/0x460 fs/namei.c:1958 lookup_last fs/namei.c:2403 [inline] path_lookupat+0x180/0x490 fs/namei.c:2427 filename_lookup+0x1d5/0x600 fs/namei.c:2460 user_path_at_empty+0x43/0x50 fs/namei.c:2740 user_path_at include/linux/namei.h:60 [inline] vfs_statx+0xff/0x520 fs/stat.c:193 vfs_fstatat fs/stat.c:215 [inline] __do_sys_newfstatat fs/stat.c:383 [inline] __se_sys_newfstatat+0xc6/0x340 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 ffff8881101c3bb0 which belongs to the cache dentry of size 208 The buggy address is located 0 bytes inside of 208-byte region [ffff8881101c3bb0, ffff8881101c3c80) The buggy address belongs to the page: page:ffffea00044070c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1101c3 flags: 0x4000000000000200(slab) raw: 4000000000000200 0000000000000000 0000000200000001 ffff88810018a480 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 106, ts 4638975791, 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+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5370 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+0x2a6/0x450 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+0x1af/0x2e0 mm/slub.c:2965 __d_alloc+0x2d/0x6a0 fs/dcache.c:1714 d_alloc fs/dcache.c:1793 [inline] d_alloc_parallel+0xd6/0x1320 fs/dcache.c:2547 __lookup_slow+0x13e/0x3e0 fs/namei.c:1625 lookup_slow+0x57/0x70 fs/namei.c:1657 walk_component+0x325/0x460 fs/namei.c:1952 lookup_last fs/namei.c:2403 [inline] path_lookupat+0x180/0x490 fs/namei.c:2427 filename_lookup+0x1d5/0x600 fs/namei.c:2460 user_path_at_empty+0x43/0x50 fs/namei.c:2740 user_path_at include/linux/namei.h:60 [inline] vfs_statx+0xff/0x520 fs/stat.c:193 page_owner free stack trace missing Memory state around the buggy address: ffff8881101c3a80: fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881101c3b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc >ffff8881101c3b80: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb ^ ffff8881101c3c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881101c3c80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ WARNING: CPU: 1 PID: 399 at fs/dcache.c:766 fast_dput+0x210/0x290 fs/dcache.c:766 Modules linked in: CPU: 1 PID: 399 Comm: syz-executor Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:fast_dput+0x210/0x290 fs/dcache.c:766 Code: 04 f3 ff e9 46 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 99 fe ff ff 48 89 df e8 3a 04 f3 ff e9 8c fe ff ff e8 90 14 b9 ff <0f> 0b e9 0b ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c e4 fe ff RSP: 0018:ffffc90000b57b80 EFLAGS: 00010293 RAX: ffffffff81aa9110 RBX: ffff8881101c3bb0 RCX: ffff88811e2f3b40 RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001 RBP: ffffc90000b57bb0 R08: 0000000000000004 R09: 0000000000000003 R10: fffff5200016af60 R11: 1ffff9200016af60 R12: 00000000ffffff80 R13: dffffc0000000000 R14: ffff8881101c3c08 R15: 1ffff11022038781 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2e5dce CR3: 0000000114a60000 CR4: 00000000003506a0 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+0x1aa/0x210 fs/incfs/vfs.c:1979 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x446/0x500 fs/namespace.c:1114 __cleanup_mnt+0x19/0x20 fs/namespace.c:1121 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa4f/0x2480 kernel/exit.c:872 do_group_exit+0x141/0x310 kernel/exit.c:986 __do_sys_exit_group kernel/exit.c:997 [inline] __se_sys_exit_group kernel/exit.c:995 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:995 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7ff85ba556c9 Code: Unable to access opcode bytes at RIP 0x7ff85ba5569f. RSP: 002b:00007ffd508c9e98 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ff85bad7ddd RCX: 00007ff85ba556c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 00007ffd508c7c37 R09: 00007ffd508cb150 R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffd508cb150 R13: 00007ff85bad7d7d R14: 000055558128f4a8 R15: 00007ffd508cc220 ---[ end trace 50a1f69a7186f870 ]---