[syzbot] [bridge?] general protection fault in br_del_frame
From: syzbot
Date: Thu Sep 03 2026 - 20:41:43 EST
Hello,
syzbot found the following issue on:
HEAD commit: 818bebeb63dd drm/xe: Don't hand out the flat CCS storage a..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1596a979580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ccca94d2c01b9e78
dashboard link: https://syzkaller.appspot.com/bug?extid=1df7473ef265fe8ba6e1
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1431e625580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-818bebeb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6e4100526b12/vmlinux-818bebeb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/723c4783ee96/bzImage-818bebeb.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1df7473ef265fe8ba6e1@xxxxxxxxxxxxxxxxxxxxxxxxx
bridge0: port 2(bridge_slave_1) entered disabled state
bridge_slave_0: left allmulticast mode
bridge_slave_0: left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI
KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]
CPU: 1 UID: 0 PID: 12 Comm: kworker/u32:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:__hlist_del include/linux/list.h:1038 [inline]
RIP: 0010:hlist_del_rcu include/linux/rculist.h:599 [inline]
RIP: 0010:br_del_frame+0x106/0x1a0 net/bridge/br_input.c:482
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 87 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 65 18 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 76 49 89 1c 24 48 85 db 74 24 e8 c6 45 72 f7 48 8d
RSP: 0018:ffffc900000f78e8 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1bd5a00000000024 RSI: ffffffff8a98bb9f RDI: ffffffff91453338
RBP: ffffffff91453320 R08: 0000000000000001 R09: 000000000000002c
R10: 0000000000000200 R11: 0000000000000001 R12: dead000000000122
R13: ffff88802e200800 R14: 000000000000001c R15: ffff88802e200800
FS: 0000000000000000(0000) GS:ffff8880d5ca2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdcf9541e9c CR3: 0000000026926000 CR4: 0000000000352ef0
Call Trace:
<TASK>
mep_delete_implementation+0x292/0x340 net/bridge/br_cfm.c:591
br_cfm_port_del+0x14f/0x1e0 net/bridge/br_cfm.c:872
del_nbp+0x168/0xd50 net/bridge/br_if.c:348
br_dev_delete+0x96/0x1c0 net/bridge/br_if.c:387
br_net_exit_rtnl+0xdb/0x140 net/bridge/br.c:414
ops_exit_rtnl_list net/core/net_namespace.c:181 [inline]
ops_undo_list+0x896/0xab0 net/core/net_namespace.c:249
cleanup_net+0x499/0x920 net/core/net_namespace.c:706
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
process_scheduled_works kernel/workqueue.c:3470 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__hlist_del include/linux/list.h:1038 [inline]
RIP: 0010:hlist_del_rcu include/linux/rculist.h:599 [inline]
RIP: 0010:br_del_frame+0x106/0x1a0 net/bridge/br_input.c:482
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 87 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 65 18 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 76 49 89 1c 24 48 85 db 74 24 e8 c6 45 72 f7 48 8d
RSP: 0018:ffffc900000f78e8 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1bd5a00000000024 RSI: ffffffff8a98bb9f RDI: ffffffff91453338
RBP: ffffffff91453320 R08: 0000000000000001 R09: 000000000000002c
R10: 0000000000000200 R11: 0000000000000001 R12: dead000000000122
R13: ffff88802e200800 R14: 000000000000001c R15: ffff88802e200800
FS: 0000000000000000(0000) GS:ffff8880d5ca2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdcf9541e9c CR3: 0000000026926000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: 00 fc add %bh,%ah
2: ff lcall (bad)
3: df 48 89 fisttps -0x77(%rax)
6: fa cli
7: 48 c1 ea 03 shr $0x3,%rdx
b: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
f: 0f 85 87 00 00 00 jne 0x9c
15: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1c: fc ff df
1f: 4c 8b 65 18 mov 0x18(%rbp),%r12
23: 4c 89 e2 mov %r12,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 75 76 jne 0xa6
30: 49 89 1c 24 mov %rbx,(%r12)
34: 48 85 db test %rbx,%rbx
37: 74 24 je 0x5d
39: e8 c6 45 72 f7 call 0xf7724604
3e: 48 rex.W
3f: 8d .byte 0x8d
---
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