syzbot


general protection fault in br_switchdev_event

Status: closed as invalid on 2025/08/27 04:07
Subsystems: bridge
[Documentation on labels]
First crash: 88d, last: 88d

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xfbd5a5d5a0000000: 0000 [#1] SMP KASAN PTI
KASAN: maybe wild-memory-access in range [0xdead4ead00000000-0xdead4ead00000007]
CPU: 1 UID: 0 PID: 3195 Comm: kworker/1:2 Not tainted 6.16.0-rc5-syzkaller-00182-g7727ec1523d7 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_long br_fdb_cleanup
RIP: 0010:netif_is_bridge_port include/linux/netdevice.h:5412 [inline]
RIP: 0010:br_port_get_rtnl_rcu net/bridge/br_private.h:465 [inline]
RIP: 0010:br_switchdev_event+0x47/0x530 net/bridge/br.c:166
Code: 00 00 fc ff df e8 79 04 7a f7 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 13 87 dd f7 4c 8b 33 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 fa 86 dd f7 49 8b 2e 48 89 ee 48
RSP: 0018:ffffc9000c11f6a0 EFLAGS: 00010a06
RAX: 1bd5a9d5a0000000 RBX: ffffc9000c11f7e0 RCX: ffff8880301a8000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff8f64e040
RBP: 00000000ffffffff R08: ffffffff8fa1f3f7 R09: 1ffffffff1f43e7e
R10: dffffc0000000000 R11: ffffffff8a4631d0 R12: 0000000000000004
R13: 0000000000000000 R14: dead4ead00000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000ffd000 CR3: 000000005365a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 atomic_notifier_call_chain+0xda/0x180 kernel/notifier.c:223
 br_switchdev_fdb_notify+0x361/0x3e0 net/bridge/br_switchdev.c:-1
 fdb_notify+0x89/0x160 net/bridge/br_fdb.c:186
 fdb_delete+0xec4/0x1160 net/bridge/br_fdb.c:324
 br_fdb_cleanup+0x2aa/0x4d0 net/bridge/br_fdb.c:568
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:netif_is_bridge_port include/linux/netdevice.h:5412 [inline]
RIP: 0010:br_port_get_rtnl_rcu net/bridge/br_private.h:465 [inline]
RIP: 0010:br_switchdev_event+0x47/0x530 net/bridge/br.c:166
Code: 00 00 fc ff df e8 79 04 7a f7 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 13 87 dd f7 4c 8b 33 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 fa 86 dd f7 49 8b 2e 48 89 ee 48
RSP: 0018:ffffc9000c11f6a0 EFLAGS: 00010a06
RAX: 1bd5a9d5a0000000 RBX: ffffc9000c11f7e0 RCX: ffff8880301a8000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff8f64e040
RBP: 00000000ffffffff R08: ffffffff8fa1f3f7 R09: 1ffffffff1f43e7e
R10: dffffc0000000000 R11: ffffffff8a4631d0 R12: 0000000000000004
R13: 0000000000000000 R14: dead4ead00000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000ffd000 CR3: 000000005365a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 4 bytes skipped:
   0:	df e8                	fucomip %st(0),%st
   2:	79 04                	jns    0x8
   4:	7a f7                	jp     0xfffffffd
   6:	48 89 d8             	mov    %rbx,%rax
   9:	48 c1 e8 03          	shr    $0x3,%rax
   d:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1)
  12:	74 08                	je     0x1c
  14:	48 89 df             	mov    %rbx,%rdi
  17:	e8 13 87 dd f7       	call   0xf7dd872f
  1c:	4c 8b 33             	mov    (%rbx),%r14
  1f:	4c 89 f0             	mov    %r14,%rax
  22:	48 c1 e8 03          	shr    $0x3,%rax
* 26:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1) <-- trapping instruction
  2b:	74 08                	je     0x35
  2d:	4c 89 f7             	mov    %r14,%rdi
  30:	e8 fa 86 dd f7       	call   0xf7dd872f
  35:	49 8b 2e             	mov    (%r14),%rbp
  38:	48 89 ee             	mov    %rbp,%rsi
  3b:	48                   	rex.W

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/12 13:14 net 7727ec1523d7 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in br_switchdev_event
* Struck through repros no longer work on HEAD.