BUG: kernel NULL pointer dereference, address: 000000000000009c #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 15732067 P4D 15732067 PUD 15733067 PMD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 1 PID: 16427 Comm: syz-executor.5 Not tainted 5.10.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:kcsan_setup_watchpoint+0x215/0x4d0 kernel/kcsan/core.c:479 Code: 9d 4c 89 74 24 50 eb 05 ff 74 24 50 9d 48 83 c4 60 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f b7 08 89 ca c1 ea 08 31 db 31 f6 eb 26 <8b> 08 89 ca c1 ea 08 89 ce c1 ee 10 eb 18 48 8b 08 48 89 ca 48 c1 RSP: 0018:ffffc90000d00de0 EFLAGS: 00010046 RAX: 000000000000009c RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: 00000000aaaaaaab R09: 000800000000009c R10: 0000000000000246 R11: ffff88803a567040 R12: 0000000000000004 R13: 0000000000000000 R14: ffffe8ffffd043c0 R15: 0000000000000001 FS: 0000000002255940(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000009c CR3: 0000000015731000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: afs_unuse_cell+0x24/0x2b0 fs/afs/cell.c:592 afs_cell_destroy+0xa1/0x210 fs/afs/cell.c:500 rcu_do_batch kernel/rcu/tree.c:2476 [inline] rcu_core+0x6bb/0xbc0 kernel/rcu/tree.c:2711 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2724 __do_softirq+0x12c/0x2b1 kernel/softirq.c:298 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0x32/0x40 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu+0xb2/0xc0 kernel/softirq.c:423 sysvec_apic_timer_interrupt+0x74/0x90 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 RIP: 0010:tomoyo_check_acl+0x70/0x200 security/tomoyo/domain.c:173 Code: 08 45 31 ed 4c 89 ff e8 fe 2f ea fe 4d 8b 27 4d 39 fc 0f 84 e2 00 00 00 66 90 49 8d 7c 24 18 e8 06 10 ea fe 45 0f b6 74 24 18 <31> ff 44 89 f6 e8 66 f5 d9 fe 45 85 f6 74 11 e8 8c f2 d9 fe e9 87 RSP: 0018:ffffc90000e13998 EFLAGS: 00000246 RAX: ffff88803a567a80 RBX: ffffc90000e13a00 RCX: 000000000000021f RDX: 000088810a4e1918 RSI: 0000000000000000 RDI: ffff88810a4e1918 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000888022f4669b R10: 0000ffffffffffff R11: 0000000000000000 R12: ffff88810a4e1900 R13: 0000000000000000 R14: 0000000000000000 R15: ffff888012ab3610 tomoyo_path_permission security/tomoyo/file.c:586 [inline] tomoyo_check_open_permission+0x17f/0x370 security/tomoyo/file.c:777 tomoyo_file_open+0xd3/0xf0 security/tomoyo/tomoyo.c:313 security_file_open+0x3f/0x90 security/security.c:1575 do_dentry_open+0x22d/0x870 fs/open.c:804 vfs_open+0x43/0x50 fs/open.c:931 do_open fs/namei.c:3252 [inline] path_openat+0x1844/0x20a0 fs/namei.c:3369 do_filp_open+0xbd/0x1d0 fs/namei.c:3396 do_sys_openat2+0xa3/0x240 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_open fs/open.c:1192 [inline] __se_sys_open fs/open.c:1188 [inline] __x64_sys_open+0xe2/0x110 fs/open.c:1188 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45bdd0 Code: 31 c0 e9 45 ff ff ff 0f 1f 00 80 3f 00 0f 84 f7 00 00 00 55 53 b9 02 00 00 00 be 00 08 09 00 89 c8 48 81 ec 98 00 00 00 0f 05 <48> 3d 00 f0 ff ff 48 89 c3 0f 87 e9 00 00 00 85 db 0f 88 2f 01 00 RSP: 002b:00007ffcc3cd8550 EFLAGS: 00000206 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00000000001ea66b RCX: 000000000045bdd0 RDX: 000000000000000c RSI: 0000000000090800 RDI: 00007ffcc3cd9730 RBP: 00000000000005af R08: 0000000000000000 R09: 0000000002255940 R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffcc3cd9730 R13: 00007ffcc3cd9720 R14: 0000000000000000 R15: 00007ffcc3cd9730 Modules linked in: CR2: 000000000000009c ---[ end trace 414e365f3c7197ae ]--- RIP: 0010:kcsan_setup_watchpoint+0x215/0x4d0 kernel/kcsan/core.c:479 Code: 9d 4c 89 74 24 50 eb 05 ff 74 24 50 9d 48 83 c4 60 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f b7 08 89 ca c1 ea 08 31 db 31 f6 eb 26 <8b> 08 89 ca c1 ea 08 89 ce c1 ee 10 eb 18 48 8b 08 48 89 ca 48 c1 RSP: 0018:ffffc90000d00de0 EFLAGS: 00010046 RAX: 000000000000009c RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000003 R08: 00000000aaaaaaab R09: 000800000000009c R10: 0000000000000246 R11: ffff88803a567040 R12: 0000000000000004 R13: 0000000000000000 R14: ffffe8ffffd043c0 R15: 0000000000000001 FS: 0000000002255940(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000009c CR3: 0000000015731000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400