kAFS: bad VL server IP address
BUG: unable to handle page fault for address: fffffffffffffffa
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD e186067 P4D e186067 PUD e188067 PMD 0
Oops: Oops: 0002 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 5834 Comm: syz-executor362 Not tainted 6.15.0-rc1-syzkaller-00025-gbec7dcbc242c #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:arch_atomic_fetch_add arch/x86/include/asm/atomic.h:93 [inline]
RIP: 0010:raw_atomic_fetch_sub_release include/linux/atomic/atomic-arch-fallback.h:949 [inline]
RIP: 0010:atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:401 [inline]
RIP: 0010:__refcount_sub_and_test include/linux/refcount.h:389 [inline]
RIP: 0010:__refcount_dec_and_test include/linux/refcount.h:432 [inline]
RIP: 0010:refcount_dec_and_test include/linux/refcount.h:450 [inline]
RIP: 0010:afs_put_vlserverlist+0x3a/0x220 fs/afs/vl_list.c:67
Code: 53 48 83 ec 18 e8 e6 35 2f fe 48 85 ed 74 43 e8 dc 35 2f fe 4c 8d 65 10 be 04 00 00 00 bb ff ff ff ff 4c 89 e7 e8 76 ad 93 fe <f0> 0f c1 5d 10 31 ff 89 de e8 f8 30 2f fe 85 db 7e 29 e8 af 35 2f
RSP: 0018:ffffc90003e5fae0 EFLAGS: 00010246
RAX: 0000000000000001 RBX: 00000000ffffffff RCX: ffffffff838c071a
RDX: fffffc0000000000 RSI: 0000000000000004 RDI: fffffffffffffffa
RBP: ffffffffffffffea R08: 0000000000000001 R09: fffffbffffffffff
R10: fffffffffffffffd R11: 0000000000000001 R12: fffffffffffffffa
R13: ffffffffffffffea R14: ffff8880216ad700 R15: ffff888034ec2000
FS: 0000555561d3e380(0000) GS:ffff888124ab9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffa CR3: 000000007a922000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
afs_alloc_cell fs/afs/cell.c:218 [inline]
afs_lookup_cell+0x12a5/0x1680 fs/afs/cell.c:264
afs_cell_init+0x17a/0x380 fs/afs/cell.c:386
afs_proc_rootcell_write+0x21f/0x290 fs/afs/proc.c:247
proc_simple_write+0x114/0x1b0 fs/proc/generic.c:825
pde_write fs/proc/inode.c:330 [inline]
proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
vfs_write+0x25c/0x1180 fs/read_write.c:682
ksys_write+0x12a/0x240 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fab4ed8ba79
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff0c666448 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007fab4ed8ba79
RDX: 000000000000009e RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fab4edfe5f0 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000000001
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
</TASK>
Modules linked in:
CR2: fffffffffffffffa
---[ end trace 0000000000000000 ]---
RIP: 0010:arch_atomic_fetch_add arch/x86/include/asm/atomic.h:93 [inline]
RIP: 0010:raw_atomic_fetch_sub_release include/linux/atomic/atomic-arch-fallback.h:949 [inline]
RIP: 0010:atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:401 [inline]
RIP: 0010:__refcount_sub_and_test include/linux/refcount.h:389 [inline]
RIP: 0010:__refcount_dec_and_test include/linux/refcount.h:432 [inline]
RIP: 0010:refcount_dec_and_test include/linux/refcount.h:450 [inline]
RIP: 0010:afs_put_vlserverlist+0x3a/0x220 fs/afs/vl_list.c:67
Code: 53 48 83 ec 18 e8 e6 35 2f fe 48 85 ed 74 43 e8 dc 35 2f fe 4c 8d 65 10 be 04 00 00 00 bb ff ff ff ff 4c 89 e7 e8 76 ad 93 fe <f0> 0f c1 5d 10 31 ff 89 de e8 f8 30 2f fe 85 db 7e 29 e8 af 35 2f
RSP: 0018:ffffc90003e5fae0 EFLAGS: 00010246
RAX: 0000000000000001 RBX: 00000000ffffffff RCX: ffffffff838c071a
RDX: fffffc0000000000 RSI: 0000000000000004 RDI: fffffffffffffffa
RBP: ffffffffffffffea R08: 0000000000000001 R09: fffffbffffffffff
R10: fffffffffffffffd R11: 0000000000000001 R12: fffffffffffffffa
R13: ffffffffffffffea R14: ffff8880216ad700 R15: ffff888034ec2000
FS: 0000555561d3e380(0000) GS:ffff888124ab9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffa CR3: 000000007a922000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 53 push %rbx
1: 48 83 ec 18 sub $0x18,%rsp
5: e8 e6 35 2f fe call 0xfe2f35f0
a: 48 85 ed test %rbp,%rbp
d: 74 43 je 0x52
f: e8 dc 35 2f fe call 0xfe2f35f0
14: 4c 8d 65 10 lea 0x10(%rbp),%r12
18: be 04 00 00 00 mov $0x4,%esi
1d: bb ff ff ff ff mov $0xffffffff,%ebx
22: 4c 89 e7 mov %r12,%rdi
25: e8 76 ad 93 fe call 0xfe93ada0
* 2a: f0 0f c1 5d 10 lock xadd %ebx,0x10(%rbp) <-- trapping instruction
2f: 31 ff xor %edi,%edi
31: 89 de mov %ebx,%esi
33: e8 f8 30 2f fe call 0xfe2f3130
38: 85 db test %ebx,%ebx
3a: 7e 29 jle 0x65
3c: e8 .byte 0xe8
3d: af scas %es:(%rdi),%eax
3e: 35 .byte 0x35
3f: 2f (bad)