R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fbc42b1f128 R14: 00007fbc42b1f090 R15: 00007ffe45c81e98 ---[ end trace ba8313724c169c50 ]--- ================================================================== BUG: KASAN: use-after-free in fast_dput+0x1e0/0x290 fs/dcache.c:750 Read of size 4 at addr ffff88812d0e7330 by task syz.6.629/2712 CPU: 0 PID: 2712 Comm: syz.6.629 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 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:1979 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:873 do_group_exit+0x149/0x310 kernel/exit.c:987 get_signal+0xfb1/0x1300 kernel/signal.c:2794 arch_do_signal_or_restart+0xe7/0x11b0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:291 RIP: 0033:0x7fbc428970d9 Code: Unable to access opcode bytes at RIP 0x7fbc428970af. RSP: 002b:00007fbc412cefd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007fbc42b1f090 RCX: 00007fbc428970d9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000011 RBP: 00007fbc4292e024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fbc42b1f128 R14: 00007fbc42b1f090 R15: 00007ffe45c81e98 Allocated by task 3947: 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:2664 incfs_lookup_dentry+0x60/0xb0 fs/incfs/data_mgmt.c:210 open_or_create_special_dir+0x4c/0x1e0 fs/incfs/vfs.c:469 incfs_mount_fs+0x434/0x8d0 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/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 12: 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:1979 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:873 do_group_exit+0x149/0x310 kernel/exit.c:987 get_signal+0xfb1/0x1300 kernel/signal.c:2794 arch_do_signal_or_restart+0xe7/0x11b0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:291 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 find_next_child fs/libfs.c:263 [inline] simple_recursive_removal+0x26d/0x720 fs/libfs.c:278 debugfs_remove+0x56/0x70 fs/debugfs/inode.c:741 kvm_destroy_vm_debugfs virt/kvm/kvm_main.c:724 [inline] kvm_destroy_vm virt/kvm/kvm_main.c:925 [inline] kvm_put_kvm+0xcb/0x10a0 virt/kvm/kvm_main.c:968 kvm_vm_release+0x46/0x50 virt/kvm/kvm_main.c:991 __fput+0x2dc/0x730 fs/file_table.c:281 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x127/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:172 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff88812d0e7330 which belongs to the cache dentry of size 208 The buggy address is located 0 bytes inside of 208-byte region [ffff88812d0e7330, ffff88812d0e7400) The buggy address belongs to the page: page:ffffea0004b439c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12d0e7 flags: 0x4000000000000200(slab) raw: 4000000000000200 ffffea0004418480 0000000200000002 ffff88810018a600 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 0x112cd0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY|__GFP_RECLAIMABLE), pid 496, ts 29461704773, 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_anon fs/dcache.c:1814 [inline] d_make_root+0x4a/0xe0 fs/dcache.c:2017 fat_fill_super+0x380a/0x4e90 fs/fat/inode.c:1870 msdos_fill_super+0x2c/0x40 fs/fat/namei_msdos.c:658 mount_bdev+0x26a/0x380 fs/super.c:1442 msdos_mount+0x34/0x40 fs/fat/namei_msdos.c:665 legacy_get_tree+0xed/0x190 fs/fs_context.c:593 vfs_get_tree+0x89/0x260 fs/super.c:1572 do_new_mount+0x25a/0xa30 fs/namespace.c:3006 page_owner free stack trace missing Memory state around the buggy address: ffff88812d0e7200: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb ffff88812d0e7280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc >ffff88812d0e7300: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb ^ ffff88812d0e7380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88812d0e7400: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ WARNING: CPU: 1 PID: 2712 at fs/dcache.c:766 fast_dput+0x207/0x290 fs/dcache.c:766 Modules linked in: CPU: 1 PID: 2712 Comm: syz.6.629 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:fast_dput+0x207/0x290 fs/dcache.c:766 Code: e0 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 e0 f2 ff e9 94 fe ff ff e8 79 6b 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:ffffc90000ca78a0 EFLAGS: 00010293 RAX: ffffffff81ac3a67 RBX: ffff88812d0e7330 RCX: ffff888115bc8000 RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001 RBP: ffffc90000ca78c8 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000194f04 R12: 00000000ffffff80 R13: dffffc0000000000 R14: ffff88812d0e7388 R15: 1ffff11025a1ce71 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000000 CR3: 000000011d15f000 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+0x1a1/0x200 fs/incfs/vfs.c:1979 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:873 do_group_exit+0x149/0x310 kernel/exit.c:987 get_signal+0xfb1/0x1300 kernel/signal.c:2794 arch_do_signal_or_restart+0xe7/0x11b0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:291 RIP: 0033:0x7fbc428970d9 Code: Unable to access opcode bytes at RIP 0x7fbc428970af. RSP: 002b:00007fbc412cefd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007fbc42b1f090 RCX: 00007fbc428970d9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000011 RBP: 00007fbc4292e024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fbc42b1f128 R14: 00007fbc42b1f090 R15: 00007ffe45c81e98 ---[ end trace ba8313724c169c51 ]--- BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 0 P4D 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 1 PID: 2712 Comm: syz.6.629 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc90000ca7840 EFLAGS: 00010246 RAX: 1ffffffff0a52aaf RBX: ffff888110612ee0 RCX: ffffffff81ac4e07 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888110612ee0 RBP: ffffc90000ca7888 R08: 0000000000000003 R09: 00000000fffffffb R10: dffffc0000000000 R11: ffffed10220c25e7 R12: 1ffff110220c25dc R13: dffffc0000000000 R14: ffffffff85295578 R15: ffff888110612f38 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000010d60d000 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:1979 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:873 do_group_exit+0x149/0x310 kernel/exit.c:987 get_signal+0xfb1/0x1300 kernel/signal.c:2794 arch_do_signal_or_restart+0xe7/0x11b0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:291 RIP: 0033:0x7fbc428970d9 Code: Unable to access opcode bytes at RIP 0x7fbc428970af. RSP: 002b:00007fbc412cefd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007fbc42b1f090 RCX: 00007fbc428970d9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000011 RBP: 00007fbc4292e024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fbc42b1f128 R14: 00007fbc42b1f090 R15: 00007ffe45c81e98 Modules linked in: CR2: 0000000000000000 ---[ end trace ba8313724c169c52 ]--- RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc90000ca7840 EFLAGS: 00010246 RAX: 1ffffffff0a52aaf RBX: ffff888110612ee0 RCX: ffffffff81ac4e07 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888110612ee0 RBP: ffffc90000ca7888 R08: 0000000000000003 R09: 00000000fffffffb R10: dffffc0000000000 R11: ffffed10220c25e7 R12: 1ffff110220c25dc R13: dffffc0000000000 R14: ffffffff85295578 R15: ffff888110612f38 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000010d60d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400