================================================================== BUG: KASAN: use-after-free in fast_dput+0x1e0/0x290 fs/dcache.c:778 Read of size 4 at addr ffff88811722d990 by task syz-executor/362 CPU: 0 PID: 362 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+0x1e0/0x290 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+0x1af/0x210 fs/incfs/vfs.c:2003 deactivate_locked_super+0xb5/0x120 fs/super.c:336 deactivate_super+0xaf/0xe0 fs/super.c:367 cleanup_mnt+0x45e/0x4e0 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+0xaf2/0x2850 kernel/exit.c:887 do_group_exit+0x21b/0x2e0 kernel/exit.c:1030 __do_sys_exit_group kernel/exit.c:1041 [inline] __se_sys_exit_group kernel/exit.c:1039 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1039 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: 0033:0x7fe4efd9ce59 Code: Unable to access opcode bytes at 0x7fe4efd9ce2f. RSP: 002b:00007ffd15686da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fe4efe3232a RCX: 00007fe4efd9ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007fe4efe322ca R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd15688060 R13: 00007fe4efe322ca R14: 0000555556fb14e8 R15: 00007ffd15689130 Allocated by task 858: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_alloc_info+0x1f/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+0x34/0x6d0 fs/dcache.c:1774 d_alloc fs/dcache.c:1854 [inline] d_alloc_parallel+0xe2/0x1280 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+0x4c/0x1f0 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+0x251/0xb40 fs/namespace.c:3081 path_mount+0x640/0xfd0 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 316: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2b/0x40 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+0x52b/0xc30 kernel/rcu/tree.c:2297 rcu_core+0x486/0xf00 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/0xf50 kernel/rcu/tree.c:2926 dentry_free+0xbd/0x150 fs/dcache.c:-1 __dentry_kill+0x535/0x680 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+0x1af/0x210 fs/incfs/vfs.c:2003 deactivate_locked_super+0xb5/0x120 fs/super.c:336 deactivate_super+0xaf/0xe0 fs/super.c:367 cleanup_mnt+0x45e/0x4e0 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+0xaf2/0x2850 kernel/exit.c:887 do_group_exit+0x21b/0x2e0 kernel/exit.c:1030 __do_sys_exit_group kernel/exit.c:1041 [inline] __se_sys_exit_group kernel/exit.c:1039 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1039 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 The buggy address belongs to the object at ffff88811722d990 which belongs to the cache dentry of size 208 The buggy address is located 0 bytes inside of 208-byte region [ffff88811722d990, ffff88811722da60) The buggy address belongs to the physical page: page:ffffea00045c8b40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11722d flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 0000000000000000 dead000000000122 ffff8881001ed500 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 858, tgid 857 (syz.5.147), ts 41330304103, free_ts 40893915384 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+0x2ca9/0x2d20 mm/page_alloc.c:4586 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1 allocate_slab mm/slub.c:1967 [inline] new_slab+0x98/0x3e0 mm/slub.c:2020 ___slab_alloc+0x70f/0xb70 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+0x34/0x6d0 fs/dcache.c:1774 d_alloc fs/dcache.c:1854 [inline] d_alloc_parallel+0xe2/0x1280 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+0x4c/0x1f0 fs/incfs/vfs.c:475 incfs_mount_fs+0x42f/0x890 fs/incfs/vfs.c:1890 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1580 [inline] free_pcp_prepare mm/page_alloc.c:1654 [inline] free_unref_page_prepare+0x80c/0x820 mm/page_alloc.c:3621 free_unref_page+0x93/0x530 mm/page_alloc.c:3719 free_the_page mm/page_alloc.c:863 [inline] __free_pages+0x67/0x100 mm/page_alloc.c:6020 __free_slab+0xc7/0x1a0 mm/slub.c:2044 free_slab mm/slub.c:2059 [inline] discard_slab mm/slub.c:2065 [inline] __unfreeze_partials+0x15a/0x190 mm/slub.c:2614 put_cpu_partial+0xa9/0x100 mm/slub.c:2690 __slab_free+0x1c4/0x280 mm/slub.c:3589 do_slab_free mm/slub.c:3666 [inline] ___cache_free+0xbf/0xd0 mm/slub.c:3722 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0xc6/0x140 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:311 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] kmem_cache_alloc_node+0x179/0x330 mm/slub.c:3429 __alloc_skb+0xe8/0x4a0 net/core/skbuff.c:508 alloc_skb include/linux/skbuff.h:1322 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline] netlink_sendmsg+0x635/0xbd0 net/netlink/af_netlink.c:1848 sock_sendmsg_nosec net/socket.c:716 [inline] __sock_sendmsg net/socket.c:728 [inline] ____sys_sendmsg+0x5fb/0x9c0 net/socket.c:2508 Memory state around the buggy address: ffff88811722d880: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811722d900: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc >ffff88811722d980: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88811722da00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88811722da80: fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== ------------[ cut here ]------------ WARNING: CPU: 1 PID: 362 at fs/dcache.c:794 fast_dput+0x207/0x290 fs/dcache.c:794 Modules linked in: CPU: 1 PID: 362 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+0x207/0x290 fs/dcache.c:794 Code: a4 f1 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 53 a4 f1 ff e9 94 fe ff ff e8 99 19 ac 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:ffffc9000dd1faf0 EFLAGS: 00010293 RAX: ffffffff81c54a97 RBX: ffff88811722d990 RCX: ffff8881157a0000 RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001 RBP: ffffc9000dd1fb18 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52001ba3f50 R12: 00000000ffffff80 R13: dffffc0000000000 R14: ffff88811722d9e8 R15: 1ffff11022e45b3d FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f19f1a57000 CR3: 000000012180f000 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+0x1af/0x210 fs/incfs/vfs.c:2003 deactivate_locked_super+0xb5/0x120 fs/super.c:336 deactivate_super+0xaf/0xe0 fs/super.c:367 cleanup_mnt+0x45e/0x4e0 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+0xaf2/0x2850 kernel/exit.c:887 do_group_exit+0x21b/0x2e0 kernel/exit.c:1030 __do_sys_exit_group kernel/exit.c:1041 [inline] __se_sys_exit_group kernel/exit.c:1039 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1039 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: 0033:0x7fe4efd9ce59 Code: Unable to access opcode bytes at 0x7fe4efd9ce2f. RSP: 002b:00007ffd15686da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fe4efe3232a RCX: 00007fe4efd9ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007fe4efe322ca R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd15688060 R13: 00007fe4efe322ca R14: 0000555556fb14e8 R15: 00007ffd15689130 ---[ 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: 362 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+0xd0/0x680 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 8e 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 bf 04 RSP: 0018:ffffc9000dd1fa98 EFLAGS: 00010246 RAX: 1ffffffff0b63087 RBX: ffff88811722ddd0 RCX: ffffffff81c56037 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88811722ddd0 RBP: ffffc9000dd1fad8 R08: 0000000000000003 R09: 00000000fffffffb R10: 00000000d47a71ee R11: 0000000000000000 R12: 1ffff11022e45bba R13: dffffc0000000000 R14: ffffffff85b18438 R15: ffff88811722de28 FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffffc CR3: 000000012180f000 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+0x1af/0x210 fs/incfs/vfs.c:2003 deactivate_locked_super+0xb5/0x120 fs/super.c:336 deactivate_super+0xaf/0xe0 fs/super.c:367 cleanup_mnt+0x45e/0x4e0 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+0xaf2/0x2850 kernel/exit.c:887 do_group_exit+0x21b/0x2e0 kernel/exit.c:1030 __do_sys_exit_group kernel/exit.c:1041 [inline] __se_sys_exit_group kernel/exit.c:1039 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1039 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: 0033:0x7fe4efd9ce59 Code: Unable to access opcode bytes at 0x7fe4efd9ce2f. RSP: 002b:00007ffd15686da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fe4efe3232a RCX: 00007fe4efd9ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000009 R08: 0000000000000000 R09: 00007fe4efe322ca R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd15688060 R13: 00007fe4efe322ca R14: 0000555556fb14e8 R15: 00007ffd15689130 Modules linked in: CR2: fffffffffffffffc ---[ end trace 0000000000000000 ]--- RIP: 0010:__dentry_kill+0xd0/0x680 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 8e 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 bf 04 RSP: 0018:ffffc9000dd1fa98 EFLAGS: 00010246 RAX: 1ffffffff0b63087 RBX: ffff88811722ddd0 RCX: ffffffff81c56037 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88811722ddd0 RBP: ffffc9000dd1fad8 R08: 0000000000000003 R09: 00000000fffffffb R10: 00000000d47a71ee R11: 0000000000000000 R12: 1ffff11022e45bba R13: dffffc0000000000 R14: ffffffff85b18438 R15: ffff88811722de28 FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffffc CR3: 000000012180f000 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 8e f1 ff call 0xfff18eda 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: bf .byte 0xbf 3f: 04 .byte 0x4