[v6.1] general protection fault in llc_conn_state_process (4)
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syzbot
2:46 PM (3 hours ago) 2:46 PM
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Hello,
syzbot found the following issue on:
HEAD commit: f2ddafa93a25 Linux 6.1.166
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17b46a02580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=9462790234ab0d068dda
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5d86a86f0032/disk-f2ddafa9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aafc10ea040b/vmlinux-f2ddafa9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f6b46858e7a5/bzImage-f2ddafa9.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+946279...@syzkaller.appspotmail.com
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 5286 Comm: syz.2.215 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:llc_conn_state_process+0xcba/0x1290 net/llc/llc_conn.c:-1
Code: 84 db 0f 94 c0 4d 8b 36 8d 54 00 01 b8 01 00 00 00 bd 07 00 00 00 0f 44 e8 4c 89 f0 48 c1 e8 03 48 bb 00 00 00 00 00 fc ff df <0f> b6 04 18 84 c0 0f 85 7e 05 00 00 41 89 16 41 0f b6 04 1c 84 c0
RSP: 0018:ffffc90000007aa8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000100
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000007 R08: ffff888030013b80 R09: 0000000000000005
R10: 0000000000000005 R11: 0000000000000100 R12: 1ffff11002eecc02
R13: ffff888017766000 R14: 0000000000000000 R15: ffff888017766012
FS: 00007f28883f66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000b000 CR3: 0000000077daf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
llc_process_tmr_ev net/llc/llc_c_ac.c:1445 [inline]
llc_conn_tmr_common_cb+0x336/0x7f0 net/llc/llc_c_ac.c:1331
call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x53e/0x800 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 0f cc 21 f7 65 8b 05 d0 50 cb 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9001d3cf740 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 76a361bddfa34d00
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffffc9001d3cf7c8 R08: ffff8880b8e28443 R09: 1ffff110171c5088
R10: dffffc0000000000 R11: ffffed10171c5089 R12: dffffc0000000000
R13: 0000000000000099 R14: ffff8880b8e28440 R15: 1ffff92003a79ee8
__try_to_del_timer_sync+0x193/0x1f0 kernel/time/timer.c:1422
__timer_delete_sync+0x21f/0x2e0 kernel/time/timer.c:1574
timer_delete_sync kernel/time/timer.c:1629 [inline]
del_timer_sync include/linux/timer.h:200 [inline]
schedule_timeout+0x18e/0x2d0 kernel/time/timer.c:2169
snd_rawmidi_write+0x3ad/0xb80 sound/core/rawmidi.c:1605
do_loop_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x4ac/0xb10 fs/read_write.c:863
vfs_writev fs/read_write.c:934 [inline]
do_writev+0x27b/0x480 fs/read_write.c:977
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: 0033:0x7f288759c799
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:00007f28883f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f2887815fa0 RCX: 00007f288759c799
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000007
RBP: 00007f2887632bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2887816038 R14: 00007f2887815fa0 R15: 00007ffe4d658a18
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:llc_conn_state_process+0xcba/0x1290 net/llc/llc_conn.c:-1
Code: 84 db 0f 94 c0 4d 8b 36 8d 54 00 01 b8 01 00 00 00 bd 07 00 00 00 0f 44 e8 4c 89 f0 48 c1 e8 03 48 bb 00 00 00 00 00 fc ff df <0f> b6 04 18 84 c0 0f 85 7e 05 00 00 41 89 16 41 0f b6 04 1c 84 c0
RSP: 0018:ffffc90000007aa8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000100
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000007 R08: ffff888030013b80 R09: 0000000000000005
R10: 0000000000000005 R11: 0000000000000100 R12: 1ffff11002eecc02
R13: ffff888017766000 R14: 0000000000000000 R15: ffff888017766012
FS: 00007f28883f66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000b000 CR3: 0000000077daf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 84 db test %bl,%bl
2: 0f 94 c0 sete %al
5: 4d 8b 36 mov (%r14),%r14
8: 8d 54 00 01 lea 0x1(%rax,%rax,1),%edx
c: b8 01 00 00 00 mov $0x1,%eax
11: bd 07 00 00 00 mov $0x7,%ebp
16: 0f 44 e8 cmove %eax,%ebp
19: 4c 89 f0 mov %r14,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
27: fc ff df
* 2a: 0f b6 04 18 movzbl (%rax,%rbx,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 7e 05 00 00 jne 0x5b4
36: 41 89 16 mov %edx,(%r14)
39: 41 0f b6 04 1c movzbl (%r12,%rbx,1),%eax
3e: 84 c0 test %al,%al
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: f2ddafa93a25 Linux 6.1.166
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17b46a02580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=9462790234ab0d068dda
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5d86a86f0032/disk-f2ddafa9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aafc10ea040b/vmlinux-f2ddafa9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f6b46858e7a5/bzImage-f2ddafa9.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+946279...@syzkaller.appspotmail.com
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 5286 Comm: syz.2.215 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:llc_conn_state_process+0xcba/0x1290 net/llc/llc_conn.c:-1
Code: 84 db 0f 94 c0 4d 8b 36 8d 54 00 01 b8 01 00 00 00 bd 07 00 00 00 0f 44 e8 4c 89 f0 48 c1 e8 03 48 bb 00 00 00 00 00 fc ff df <0f> b6 04 18 84 c0 0f 85 7e 05 00 00 41 89 16 41 0f b6 04 1c 84 c0
RSP: 0018:ffffc90000007aa8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000100
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000007 R08: ffff888030013b80 R09: 0000000000000005
R10: 0000000000000005 R11: 0000000000000100 R12: 1ffff11002eecc02
R13: ffff888017766000 R14: 0000000000000000 R15: ffff888017766012
FS: 00007f28883f66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000b000 CR3: 0000000077daf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
llc_process_tmr_ev net/llc/llc_c_ac.c:1445 [inline]
llc_conn_tmr_common_cb+0x336/0x7f0 net/llc/llc_c_ac.c:1331
call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x53e/0x800 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 0f cc 21 f7 65 8b 05 d0 50 cb 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9001d3cf740 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 76a361bddfa34d00
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffffc9001d3cf7c8 R08: ffff8880b8e28443 R09: 1ffff110171c5088
R10: dffffc0000000000 R11: ffffed10171c5089 R12: dffffc0000000000
R13: 0000000000000099 R14: ffff8880b8e28440 R15: 1ffff92003a79ee8
__try_to_del_timer_sync+0x193/0x1f0 kernel/time/timer.c:1422
__timer_delete_sync+0x21f/0x2e0 kernel/time/timer.c:1574
timer_delete_sync kernel/time/timer.c:1629 [inline]
del_timer_sync include/linux/timer.h:200 [inline]
schedule_timeout+0x18e/0x2d0 kernel/time/timer.c:2169
snd_rawmidi_write+0x3ad/0xb80 sound/core/rawmidi.c:1605
do_loop_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x4ac/0xb10 fs/read_write.c:863
vfs_writev fs/read_write.c:934 [inline]
do_writev+0x27b/0x480 fs/read_write.c:977
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: 0033:0x7f288759c799
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:00007f28883f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f2887815fa0 RCX: 00007f288759c799
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000007
RBP: 00007f2887632bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2887816038 R14: 00007f2887815fa0 R15: 00007ffe4d658a18
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:llc_conn_state_process+0xcba/0x1290 net/llc/llc_conn.c:-1
Code: 84 db 0f 94 c0 4d 8b 36 8d 54 00 01 b8 01 00 00 00 bd 07 00 00 00 0f 44 e8 4c 89 f0 48 c1 e8 03 48 bb 00 00 00 00 00 fc ff df <0f> b6 04 18 84 c0 0f 85 7e 05 00 00 41 89 16 41 0f b6 04 1c 84 c0
RSP: 0018:ffffc90000007aa8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000100
RDX: 0000000000000001 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000007 R08: ffff888030013b80 R09: 0000000000000005
R10: 0000000000000005 R11: 0000000000000100 R12: 1ffff11002eecc02
R13: ffff888017766000 R14: 0000000000000000 R15: ffff888017766012
FS: 00007f28883f66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000b000 CR3: 0000000077daf000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 84 db test %bl,%bl
2: 0f 94 c0 sete %al
5: 4d 8b 36 mov (%r14),%r14
8: 8d 54 00 01 lea 0x1(%rax,%rax,1),%edx
c: b8 01 00 00 00 mov $0x1,%eax
11: bd 07 00 00 00 mov $0x7,%ebp
16: 0f 44 e8 cmove %eax,%ebp
19: 4c 89 f0 mov %r14,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
27: fc ff df
* 2a: 0f b6 04 18 movzbl (%rax,%rbx,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 7e 05 00 00 jne 0x5b4
36: 41 89 16 mov %edx,(%r14)
39: 41 0f b6 04 1c movzbl (%r12,%rbx,1),%eax
3e: 84 c0 test %al,%al
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
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