BUG: kernel NULL pointer dereference, address: 000000000000009c
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 19322067 P4D 19322067 PUD 19321067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 7807 Comm: syz-executor.1 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:ffffc9001887fcf0 EFLAGS: 00010046
RAX: 000000000000009c RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 00000000aaaaaaab R09: 000800000000009c
R10: 0000000000000246 R11: ffff888062844040 R12: 0000000000000004
R13: 0000000000000000 R14: 0000000000000292 R15: 0000000000000001
FS:  00007f0fc91b2700(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000009c CR3: 0000000019323000 CR4: 00000000001526f0
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_free_fc+0x82/0xb0 fs/afs/super.c:611
 put_fs_context+0xbe/0x490 fs/fs_context.c:446
 path_mount+0x17e4/0x1c10 fs/namespace.c:2879
 do_mount fs/namespace.c:3218 [inline]
 __do_sys_mount fs/namespace.c:3426 [inline]
 __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3403
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3403
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x46089a
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 8a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f0fc91b1a88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0fc91b1b20 RCX: 000000000046089a
RDX: 0000000020000240 RSI: 0000000020000640 RDI: 0000000000000000
RBP: 00007f0fc91b1ae0 R08: 00007f0fc91b1b20 R09: 0000000020000240
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000240
R13: 0000000020000640 R14: 0000000000000000 R15: 0000000020000380
Modules linked in:
CR2: 000000000000009c
---[ end trace 5e64522415be024e ]---
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:ffffc9001887fcf0 EFLAGS: 00010046
RAX: 000000000000009c RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 00000000aaaaaaab R09: 000800000000009c
R10: 0000000000000246 R11: ffff888062844040 R12: 0000000000000004
R13: 0000000000000000 R14: 0000000000000292 R15: 0000000000000001
FS:  00007f0fc91b2700(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000009c CR3: 0000000019323000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400