================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:102 [inline] BUG: KASAN: null-ptr-deref in atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:541 [inline] BUG: KASAN: null-ptr-deref in queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] BUG: KASAN: null-ptr-deref in do_raw_spin_lock include/linux/spinlock.h:187 [inline] BUG: KASAN: null-ptr-deref in __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline] BUG: KASAN: null-ptr-deref in _raw_spin_lock+0x87/0xf0 kernel/locking/spinlock.c:154 Write of size 4 at addr 0000000000000904 by task syz.6.86/677 CPU: 1 PID: 677 Comm: syz.6.86 Not tainted 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_report+0x3d/0x60 mm/kasan/report.c:423 kasan_report+0x122/0x150 mm/kasan/report.c:524 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37 instrument_atomic_read_write include/linux/instrumented.h:102 [inline] atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:541 [inline] queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] do_raw_spin_lock include/linux/spinlock.h:187 [inline] __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline] _raw_spin_lock+0x87/0xf0 kernel/locking/spinlock.c:154 class_raw_spinlock_constructor include/linux/spinlock.h:498 [inline] remove_waiter+0xdd/0x750 kernel/locking/rtmutex.c:1478 rt_mutex_start_proxy_lock+0x40/0xb0 kernel/locking/rtmutex_api.c:353 futex_requeue+0xff4/0x1330 kernel/futex/requeue.c:629 do_futex+0x25e/0x430 kernel/futex/syscalls.c:-1 __do_sys_futex kernel/futex/syscalls.c:213 [inline] __se_sys_futex+0x136/0x310 kernel/futex/syscalls.c:194 __x64_sys_futex+0xe5/0x100 kernel/futex/syscalls.c:194 x64_sys_call+0x7ec/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:203 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: 0033:0x7f37a959de59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f37aa4a7028 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f37a9826180 RCX: 00007f37a959de59 RDX: 0000000000000001 RSI: 000000000000000c RDI: 000020000000cffc RBP: 00007f37a9633e6f R08: 0000200000048000 R09: 0000000000000000 R10: 0000200000000040 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f37a9826218 R14: 00007f37a9826180 R15: 00007ffd6376b508 ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000904 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 11ca71067 P4D 11ca71067 PUD 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 1 PID: 677 Comm: syz.6.86 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:202 [inline] RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:543 [inline] RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] RIP: 0010:do_raw_spin_lock include/linux/spinlock.h:187 [inline] RIP: 0010:__raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline] RIP: 0010:_raw_spin_lock+0x9d/0xf0 kernel/locking/spinlock.c:154 Code: 44 24 20 00 00 00 00 48 89 df be 04 00 00 00 e8 89 f6 b5 fc 4c 89 f7 be 04 00 00 00 e8 7c f6 b5 fc 8b 44 24 20 b9 01 00 00 00 0f b1 0b 75 33 43 c6 44 27 04 f8 48 c7 04 24 0e 36 e0 45 4b c7 RSP: 0018:ffffc900015ff940 EFLAGS: 00010097 RAX: 0000000000000000 RBX: 0000000000000904 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900015ff960 RBP: ffffc900015ff9d0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520002bff2c R12: dffffc0000000000 R13: ffff88811b6b6f20 R14: ffffc900015ff960 R15: 1ffff920002bff28 FS: 00007f37aa4a76c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000904 CR3: 000000011d6ca000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: class_raw_spinlock_constructor include/linux/spinlock.h:498 [inline] remove_waiter+0xdd/0x750 kernel/locking/rtmutex.c:1478 rt_mutex_start_proxy_lock+0x40/0xb0 kernel/locking/rtmutex_api.c:353 futex_requeue+0xff4/0x1330 kernel/futex/requeue.c:629 do_futex+0x25e/0x430 kernel/futex/syscalls.c:-1 __do_sys_futex kernel/futex/syscalls.c:213 [inline] __se_sys_futex+0x136/0x310 kernel/futex/syscalls.c:194 __x64_sys_futex+0xe5/0x100 kernel/futex/syscalls.c:194 x64_sys_call+0x7ec/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:203 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: 0033:0x7f37a959de59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f37aa4a7028 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f37a9826180 RCX: 00007f37a959de59 RDX: 0000000000000001 RSI: 000000000000000c RDI: 000020000000cffc RBP: 00007f37a9633e6f R08: 0000200000048000 R09: 0000000000000000 R10: 0000200000000040 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f37a9826218 R14: 00007f37a9826180 R15: 00007ffd6376b508 Modules linked in: CR2: 0000000000000904 ---[ end trace 0000000000000000 ]--- RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:202 [inline] RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:543 [inline] RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] RIP: 0010:do_raw_spin_lock include/linux/spinlock.h:187 [inline] RIP: 0010:__raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline] RIP: 0010:_raw_spin_lock+0x9d/0xf0 kernel/locking/spinlock.c:154 Code: 44 24 20 00 00 00 00 48 89 df be 04 00 00 00 e8 89 f6 b5 fc 4c 89 f7 be 04 00 00 00 e8 7c f6 b5 fc 8b 44 24 20 b9 01 00 00 00 0f b1 0b 75 33 43 c6 44 27 04 f8 48 c7 04 24 0e 36 e0 45 4b c7 RSP: 0018:ffffc900015ff940 EFLAGS: 00010097 RAX: 0000000000000000 RBX: 0000000000000904 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900015ff960 RBP: ffffc900015ff9d0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520002bff2c R12: dffffc0000000000 R13: ffff88811b6b6f20 R14: ffffc900015ff960 R15: 1ffff920002bff28 FS: 00007f37aa4a76c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000904 CR3: 000000011d6ca000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 44 24 20 rex.R and $0x20,%al 3: 00 00 add %al,(%rax) 5: 00 00 add %al,(%rax) 7: 48 89 df mov %rbx,%rdi a: be 04 00 00 00 mov $0x4,%esi f: e8 89 f6 b5 fc call 0xfcb5f69d 14: 4c 89 f7 mov %r14,%rdi 17: be 04 00 00 00 mov $0x4,%esi 1c: e8 7c f6 b5 fc call 0xfcb5f69d 21: 8b 44 24 20 mov 0x20(%rsp),%eax 25: b9 01 00 00 00 mov $0x1,%ecx * 2a: f0 0f b1 0b lock cmpxchg %ecx,(%rbx) <-- trapping instruction 2e: 75 33 jne 0x63 30: 43 c6 44 27 04 f8 movb $0xf8,0x4(%r15,%r12,1) 36: 48 c7 04 24 0e 36 e0 movq $0x45e0360e,(%rsp) 3d: 45 3e: 4b rex.WXB 3f: c7 .byte 0xc7