RAX: fffffffffffffdfc RBX: 00007f4b95cfd080 RCX: 00007f4b95b08225 RDX: 00007f4b9411cfc0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f4b95b57ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f4b95cfd080 R15: 00007fff9ea2a5e8 ---[ end trace 86fdbccd86394067 ]--- ================================================================== BUG: KASAN: null-ptr-deref in atomic_add_return include/asm-generic/atomic-instrumented.h:71 [inline] BUG: KASAN: null-ptr-deref in atomic_inc_return include/linux/atomic-fallback.h:284 [inline] BUG: KASAN: null-ptr-deref in ihold+0x20/0x60 fs/inode.c:421 Write of size 4 at addr 0000000000000160 by task syz.5.383/1922 CPU: 1 PID: 1922 Comm: syz.5.383 Tainted: G W 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack+0x1e/0x20 lib/dump_stack.c:77 dump_stack+0x15b/0x1b8 lib/dump_stack.c:118 __kasan_report+0xe4/0x120 mm/kasan/report.c:520 kasan_report+0x30/0x60 mm/kasan/common.c:653 check_memory_region_inline mm/kasan/generic.c:141 [inline] check_memory_region+0x274/0x280 mm/kasan/generic.c:191 __kasan_check_write+0x14/0x20 mm/kasan/common.c:99 atomic_add_return include/asm-generic/atomic-instrumented.h:71 [inline] atomic_inc_return include/linux/atomic-fallback.h:284 [inline] ihold+0x20/0x60 fs/inode.c:421 d_delete_notify include/linux/fsnotify.h:227 [inline] vfs_rmdir+0x247/0x3e0 fs/namei.c:4040 incfs_kill_sb+0xfe/0x210 fs/incfs/vfs.c:1944 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0x14f/0x1d0 fs/super.c:366 cleanup_mnt+0x446/0x500 fs/namespace.c:1102 __cleanup_mnt+0x19/0x20 fs/namespace.c:1109 task_work_run+0x146/0x170 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa43/0x2660 kernel/exit.c:861 do_group_exit+0x13e/0x300 kernel/exit.c:984 get_signal+0xdee/0x13d0 kernel/signal.c:2738 do_signal+0xad/0xda0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc4/0x1b0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194 syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x13e/0x170 arch/x86/entry/common.c:300 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7f4b95b08225 Code: Bad RIP value. RSP: 002b:00007f4b9411cf80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007f4b95cfd080 RCX: 00007f4b95b08225 RDX: 00007f4b9411cfc0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f4b95b57ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f4b95cfd080 R15: 00007fff9ea2a5e8 ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000160 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 1 PID: 1922 Comm: syz.5.383 Tainted: G B W 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:arch_atomic_add_return arch/x86/include/asm/atomic.h:167 [inline] RIP: 0010:atomic_add_return include/asm-generic/atomic-instrumented.h:72 [inline] RIP: 0010:atomic_inc_return include/linux/atomic-fallback.h:284 [inline] RIP: 0010:ihold+0x26/0x60 fs/inode.c:421 Code: 00 00 00 00 55 48 89 e5 41 56 53 48 89 fb e8 61 c8 c5 ff 48 8d bb 60 01 00 00 be 04 00 00 00 e8 a0 9c f3 ff 41 be 01 00 00 00 <f0> 44 0f c1 b3 60 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 81 RSP: 0018:ffff8881ded577c0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8881e0560fc0 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff RBP: ffff8881ded577d0 R08: 0000000000000004 R09: 0000000000000003 R10: fffffbfff0ca7a5c R11: 1ffffffff0ca7a5c R12: 1ffff1103da3b8b0 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f4b9411d6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000160 CR3: 0000000005c0e000 CR4: 00000000003426a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: d_delete_notify include/linux/fsnotify.h:227 [inline] vfs_rmdir+0x247/0x3e0 fs/namei.c:4040 incfs_kill_sb+0xfe/0x210 fs/incfs/vfs.c:1944 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0x14f/0x1d0 fs/super.c:366 cleanup_mnt+0x446/0x500 fs/namespace.c:1102 __cleanup_mnt+0x19/0x20 fs/namespace.c:1109 task_work_run+0x146/0x170 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa43/0x2660 kernel/exit.c:861 do_group_exit+0x13e/0x300 kernel/exit.c:984 get_signal+0xdee/0x13d0 kernel/signal.c:2738 do_signal+0xad/0xda0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0xc4/0x1b0 arch/x86/entry/common.c:159 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194 syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x13e/0x170 arch/x86/entry/common.c:300 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7f4b95b08225 Code: Bad RIP value. RSP: 002b:00007f4b9411cf80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007f4b95cfd080 RCX: 00007f4b95b08225 RDX: 00007f4b9411cfc0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f4b95b57ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f4b95cfd080 R15: 00007fff9ea2a5e8 Modules linked in: CR2: 0000000000000160 ---[ end trace 86fdbccd86394068 ]--- RIP: 0010:arch_atomic_add_return arch/x86/include/asm/atomic.h:167 [inline] RIP: 0010:atomic_add_return include/asm-generic/atomic-instrumented.h:72 [inline] RIP: 0010:atomic_inc_return include/linux/atomic-fallback.h:284 [inline] RIP: 0010:ihold+0x26/0x60 fs/inode.c:421 Code: 00 00 00 00 55 48 89 e5 41 56 53 48 89 fb e8 61 c8 c5 ff 48 8d bb 60 01 00 00 be 04 00 00 00 e8 a0 9c f3 ff 41 be 01 00 00 00 <f0> 44 0f c1 b3 60 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 81 RSP: 0018:ffff8881ded577c0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8881e0560fc0 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff RBP: ffff8881ded577d0 R08: 0000000000000004 R09: 0000000000000003 R10: fffffbfff0ca7a5c R11: 1ffffffff0ca7a5c R12: 1ffff1103da3b8b0 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f4b9411d6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4b95b081fb CR3: 0000000005c0e000 CR4: 00000000003426a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 00 00 add %al,(%rax) 4: 55 push %rbp 5: 48 89 e5 mov %rsp,%rbp 8: 41 56 push %r14 a: 53 push %rbx b: 48 89 fb mov %rdi,%rbx e: e8 61 c8 c5 ff call 0xffc5c874 13: 48 8d bb 60 01 00 00 lea 0x160(%rbx),%rdi 1a: be 04 00 00 00 mov $0x4,%esi 1f: e8 a0 9c f3 ff call 0xfff39cc4 24: 41 be 01 00 00 00 mov $0x1,%r14d * 2a: f0 44 0f c1 b3 60 01 lock xadd %r14d,0x160(%rbx) <-- trapping instruction 31: 00 00 33: 41 ff c6 inc %r14d 36: bf 02 00 00 00 mov $0x2,%edi 3b: 44 89 f6 mov %r14d,%esi 3e: e8 .byte 0xe8 3f: 81 .byte 0x81