---[ end trace 0000000000000000 ]--- ================================================================== BUG: KASAN: use-after-free in fast_dput+0x1e9/0x290 fs/dcache.c:778 Read of size 4 at addr ffff88810c10a990 by task syz-executor/1525 CPU: 0 PID: 1525 Comm: syz-executor Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:88 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106 print_address_description+0x71/0x200 mm/kasan/report.c:316 print_report+0x4a/0x60 mm/kasan/report.c:420 kasan_report+0x122/0x150 mm/kasan/report.c:524 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:350 fast_dput+0x1e9/0x290 fs/dcache.c:778 dput+0x21/0x80 fs/dcache.c:905 incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1b8/0x220 fs/incfs/vfs.c:2003 deactivate_locked_super+0xb5/0x120 fs/super.c:336 deactivate_super+0xaf/0xe0 fs/super.c:367 cleanup_mnt+0x474/0x500 fs/namespace.c:1192 __cleanup_mnt+0x19/0x20 fs/namespace.c:1199 task_work_run+0x1e1/0x250 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0xa35/0x2660 kernel/exit.c:886 do_group_exit+0x225/0x2e0 kernel/exit.c:1029 __do_sys_exit_group kernel/exit.c:1040 [inline] __se_sys_exit_group kernel/exit.c:1038 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1038 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f516259ce59 Code: Unable to access opcode bytes at 0x7f516259ce2f. RSP: 002b:00007ffc8651c458 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f516263222a RCX: 00007f516259ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007f51626321ca R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc8651d710 R13: 00007f51626321ca R14: 000055557ed524e8 R15: 00007ffc8651e7e0 Allocated by task 2001: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505 __kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:334 kasan_slab_alloc include/linux/kasan.h:202 [inline] slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768 slab_alloc_node mm/slub.c:3382 [inline] slab_alloc mm/slub.c:3392 [inline] __kmem_cache_alloc_lru mm/slub.c:3399 [inline] kmem_cache_alloc_lru+0x104/0x280 mm/slub.c:3415 __d_alloc+0x34/0x6c0 fs/dcache.c:1774 d_alloc fs/dcache.c:1854 [inline] d_alloc_parallel+0xe2/0x12e0 fs/dcache.c:2647 __lookup_slow+0x14f/0x410 fs/namei.c:1682 lookup_one_len+0x19d/0x2e0 fs/namei.c:2747 incfs_lookup_dentry+0x60/0xb0 fs/incfs/data_mgmt.c:210 open_or_create_special_dir+0x4f/0x1d0 fs/incfs/vfs.c:475 incfs_mount_fs+0x42f/0x890 fs/incfs/vfs.c:1890 legacy_get_tree+0xfe/0x1a0 fs/fs_context.c:632 vfs_get_tree+0x9a/0x270 fs/super.c:1578 do_new_mount+0x251/0xb30 fs/namespace.c:3081 path_mount+0x659/0xfc0 fs/namespace.c:3411 do_mount fs/namespace.c:3424 [inline] __do_sys_mount fs/namespace.c:3632 [inline] __se_sys_mount+0x320/0x390 fs/namespace.c:3609 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3609 x64_sys_call+0x65d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 2021: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x31/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250 kasan_slab_free include/linux/kasan.h:178 [inline] slab_free_hook mm/slub.c:1750 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776 slab_free mm/slub.c:3712 [inline] kmem_cache_free+0x12d/0x300 mm/slub.c:3737 __d_free+0x23/0x30 fs/dcache.c:298 rcu_do_batch+0x52a/0xbc0 kernel/rcu/tree.c:2297 rcu_core+0x5c3/0xe80 kernel/rcu/tree.c:2557 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2574 handle_softirqs+0x1d7/0x600 kernel/softirq.c:642 __do_softirq kernel/softirq.c:680 [inline] invoke_softirq kernel/softirq.c:497 [inline] __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729 irq_exit_rcu+0x9/0x10 kernel/softirq.c:741 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496 __call_rcu_common kernel/rcu/tree.c:2807 [inline] call_rcu+0xcf/0xf90 kernel/rcu/tree.c:2926 dentry_free+0xbd/0x150 fs/dcache.c:-1 __dentry_kill+0x529/0x670 fs/dcache.c:625 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:918 incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1b8/0x220 fs/incfs/vfs.c:2003 deactivate_locked_super+0xb5/0x120 fs/super.c:336 deactivate_super+0xaf/0xe0 fs/super.c:367 cleanup_mnt+0x474/0x500 fs/namespace.c:1192 __cleanup_mnt+0x19/0x20 fs/namespace.c:1199 task_work_run+0x1e1/0x250 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0xa35/0x2660 kernel/exit.c:886 do_group_exit+0x225/0x2e0 kernel/exit.c:1029 __do_sys_exit_group kernel/exit.c:1040 [inline] __se_sys_exit_group kernel/exit.c:1038 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1038 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Second to last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496 __call_rcu_common kernel/rcu/tree.c:2807 [inline] call_rcu+0xcf/0xf90 kernel/rcu/tree.c:2926 dentry_free+0xbd/0x150 fs/dcache.c:-1 __dentry_kill+0x529/0x670 fs/dcache.c:625 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:918 handle_mounts fs/namei.c:1558 [inline] step_into+0xa35/0xf40 fs/namei.c:1843 open_last_lookups fs/namei.c:3580 [inline] path_openat+0x166c/0x2f80 fs/namei.c:3787 do_filp_open+0x1f1/0x430 fs/namei.c:3817 do_sys_openat2+0x15e/0x810 fs/open.c:1343 do_sys_open fs/open.c:1359 [inline] __do_sys_openat fs/open.c:1375 [inline] __se_sys_openat fs/open.c:1370 [inline] __x64_sys_openat+0x136/0x160 fs/open.c:1370 x64_sys_call+0x783/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:258 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88810c10a990 which belongs to the cache dentry of size 208 The buggy address is located 0 bytes inside of 208-byte region [ffff88810c10a990, ffff88810c10aa60) The buggy address belongs to the physical page: page:ffffea0004304280 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10c10a flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 ffffea0004455700 dead000000000003 ffff8881001eca80 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, tgid 106 (udevd), ts 5189483539, free_ts 0 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4585 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5929 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1 allocate_slab mm/slub.c:1967 [inline] new_slab+0x98/0x3d0 mm/slub.c:2020 ___slab_alloc+0x6bd/0xb20 mm/slub.c:3177 __slab_alloc+0x5e/0xa0 mm/slub.c:3263 slab_alloc_node mm/slub.c:3348 [inline] slab_alloc mm/slub.c:3392 [inline] __kmem_cache_alloc_lru mm/slub.c:3399 [inline] kmem_cache_alloc_lru+0x144/0x280 mm/slub.c:3415 __d_alloc+0x34/0x6c0 fs/dcache.c:1774 d_alloc fs/dcache.c:1854 [inline] d_alloc_parallel+0xe2/0x12e0 fs/dcache.c:2647 __lookup_slow+0x14f/0x410 fs/namei.c:1682 lookup_slow+0x57/0x70 fs/namei.c:1714 walk_component fs/namei.c:2005 [inline] link_path_walk+0x953/0xe80 fs/namei.c:2332 path_parentat fs/namei.c:2533 [inline] __filename_parentat+0x226/0x650 fs/namei.c:2557 filename_parentat fs/namei.c:2575 [inline] do_unlinkat+0xeb/0x6d0 fs/namei.c:4368 page_owner free stack trace missing Memory state around the buggy address: ffff88810c10a880: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810c10a900: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc >ffff88810c10a980: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810c10aa00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88810c10aa80: fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== ------------[ cut here ]------------ WARNING: CPU: 1 PID: 1525 at fs/dcache.c:794 fast_dput+0x210/0x290 fs/dcache.c:794 Modules linked in: CPU: 1 PID: 1525 Comm: syz-executor Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:fast_dput+0x210/0x290 fs/dcache.c:794 Code: 97 f1 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 5a 97 f1 ff e9 8c fe ff ff e8 50 f2 ab 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:ffffc90000e57ad0 EFLAGS: 00010293 RAX: ffffffff81c58930 RBX: ffff88810c10a990 RCX: ffff88811d65a880 RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001 RBP: ffffc90000e57b00 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520001caf4c R12: 00000000ffffff80 R13: dffffc0000000000 R14: ffff88810c10a9e8 R15: 1ffff1102182153d FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000003000 CR3: 000000012a56c000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dput+0x21/0x80 fs/dcache.c:905 incfs_free_mount_info+0x60/0x200 fs/incfs/data_mgmt.c:166 incfs_kill_sb+0x1b8/0x220 fs/incfs/vfs.c:2003 deactivate_locked_super+0xb5/0x120 fs/super.c:336 deactivate_super+0xaf/0xe0 fs/super.c:367 cleanup_mnt+0x474/0x500 fs/namespace.c:1192 __cleanup_mnt+0x19/0x20 fs/namespace.c:1199 task_work_run+0x1e1/0x250 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0xa35/0x2660 kernel/exit.c:886 do_group_exit+0x225/0x2e0 kernel/exit.c:1029 __do_sys_exit_group kernel/exit.c:1040 [inline] __se_sys_exit_group kernel/exit.c:1038 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1038 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f516259ce59 Code: Unable to access opcode bytes at 0x7f516259ce2f. RSP: 002b:00007ffc8651c458 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f516263222a RCX: 00007f516259ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007f51626321ca R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc8651d710 R13: 00007f51626321ca R14: 000055557ed524e8 R15: 00007ffc8651e7e0 ---[ end trace 0000000000000000 ]--- BUG: unable to handle page fault for address: fffffffffffffffc #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 7012067 P4D 7012067 PUD 7014067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 1525 Comm: syz-executor Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__dentry_kill+0xd0/0x670 fs/dcache.c:599 Code: ff 4d 8b 36 49 83 c6 38 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 bc 81 f1 ff 48 89 df 4d 8b 1e 41 ba ee 71 7a d4 <45> 03 53 fc 74 02 0f 0b 41 ff d3 43 0f b6 04 2c 84 c0 0f 85 b3 04 RSP: 0018:ffffc90000e57a78 EFLAGS: 00010246 RAX: 1ffffffff0b6307f RBX: ffff88810c10acc0 RCX: ffffffff81c59ed7 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88810c10acc0 RBP: ffffc90000e57ac0 R08: 0000000000000003 R09: fffffffffffffffb R10: 00000000d47a71ee R11: 0000000000000000 R12: 1ffff11021821598 R13: dffffc0000000000 R14: ffffffff85b183f8 R15: ffff88810c10ad18 FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffffc CR3: 000000012a56c000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:918 incfs_free_mount_info+0x80/0x200 fs/incfs/data_mgmt.c:167 incfs_kill_sb+0x1b8/0x220 fs/incfs/vfs.c:2003 deactivate_locked_super+0xb5/0x120 fs/super.c:336 deactivate_super+0xaf/0xe0 fs/super.c:367 cleanup_mnt+0x474/0x500 fs/namespace.c:1192 __cleanup_mnt+0x19/0x20 fs/namespace.c:1199 task_work_run+0x1e1/0x250 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0xa35/0x2660 kernel/exit.c:886 do_group_exit+0x225/0x2e0 kernel/exit.c:1029 __do_sys_exit_group kernel/exit.c:1040 [inline] __se_sys_exit_group kernel/exit.c:1038 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1038 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f516259ce59 Code: Unable to access opcode bytes at 0x7f516259ce2f. RSP: 002b:00007ffc8651c458 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f516263222a RCX: 00007f516259ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007f51626321ca R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc8651d710 R13: 00007f51626321ca R14: 000055557ed524e8 R15: 00007ffc8651e7e0 Modules linked in: CR2: fffffffffffffffc ---[ end trace 0000000000000000 ]--- RIP: 0010:__dentry_kill+0xd0/0x670 fs/dcache.c:599 Code: ff 4d 8b 36 49 83 c6 38 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 bc 81 f1 ff 48 89 df 4d 8b 1e 41 ba ee 71 7a d4 <45> 03 53 fc 74 02 0f 0b 41 ff d3 43 0f b6 04 2c 84 c0 0f 85 b3 04 RSP: 0018:ffffc90000e57a78 EFLAGS: 00010246 RAX: 1ffffffff0b6307f RBX: ffff88810c10acc0 RCX: ffffffff81c59ed7 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88810c10acc0 RBP: ffffc90000e57ac0 R08: 0000000000000003 R09: fffffffffffffffb R10: 00000000d47a71ee R11: 0000000000000000 R12: 1ffff11021821598 R13: dffffc0000000000 R14: ffffffff85b183f8 R15: ffff88810c10ad18 FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffffc CR3: 000000012a56c000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: ff 4d 8b decl -0x75(%rbp) 3: 36 49 83 c6 38 ss add $0x38,%r14 8: 4c 89 f0 mov %r14,%rax b: 48 c1 e8 03 shr $0x3,%rax f: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) 14: 74 08 je 0x1e 16: 4c 89 f7 mov %r14,%rdi 19: e8 bc 81 f1 ff call 0xfff181da 1e: 48 89 df mov %rbx,%rdi 21: 4d 8b 1e mov (%r14),%r11 24: 41 ba ee 71 7a d4 mov $0xd47a71ee,%r10d * 2a: 45 03 53 fc add -0x4(%r11),%r10d <-- trapping instruction 2e: 74 02 je 0x32 30: 0f 0b ud2 32: 41 ff d3 call *%r11 35: 43 0f b6 04 2c movzbl (%r12,%r13,1),%eax 3a: 84 c0 test %al,%al 3c: 0f .byte 0xf 3d: 85 .byte 0x85 3e: b3 04 mov $0x4,%bl