syzbot


general protection fault in __ip_mc_dec_group

Status: moderation: reported on 2025/05/04 19:11
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+a4644a622c6258e245a7@syzkaller.appspotmail.com
First crash: 1d08h, last: 1h25m

Sample crash report:
batman_adv: batadv0: Removing interface: batadv_slave_1
veth1_macvtap: left promiscuous mode
veth0_macvtap: left promiscuous mode
veth1_vlan: left promiscuous mode
veth0_vlan: left promiscuous mode
Oops: general protection fault, probably for non-canonical address 0xdffffc001fffe1ac: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x00000000ffff0d60-0x00000000ffff0d67]
CPU: 0 UID: 0 PID: 8026 Comm: kworker/u8:23 Not tainted 6.15.0-rc4-syzkaller-00147-gebd297a2affa #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: netns cleanup_net
RIP: 0010:ip_mc_hash_remove net/ipv4/igmp.c:1431 [inline]
RIP: 0010:__ip_mc_dec_group+0x2fd/0x690 net/ipv4/igmp.c:1774
Code: 89 e5 de f7 c6 05 d0 e2 87 05 01 48 c7 c7 c0 88 7a 8c be 97 05 00 00 48 c7 c2 40 89 7a 8c e8 9a 5d bd f7 4c 89 e3 48 c1 eb 03 <42> 80 3c 2b 00 74 08 4c 89 e7 e8 54 da 40 f8 4d 8b 2c 24 4d 39 f5
RSP: 0018:ffffc900036bf4d8 EFLAGS: 00010206
RAX: ffffffff89e0da8e RBX: 000000001fffe1ac RCX: ffff88805d493c00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88805ef23820 R08: ffffffff8f2f41e7 R09: 1ffffffff1e5e83c
R10: dffffc0000000000 R11: fffffbfff1e5e83d R12: 00000000ffff0d60
R13: dffffc0000000000 R14: ffff88807b4c3800 R15: 1ffff1100bde4704
FS:  0000000000000000(0000) GS:ffff8881260cc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555836cd808 CR3: 000000007d758000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 inetdev_event+0x2a7/0x15b0 net/ipv4/devinet.c:1642
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
 call_netdevice_notifiers net/core/dev.c:2228 [inline]
 dev_close_many+0x29c/0x410 net/core/dev.c:1731
 unregister_netdevice_many_notify+0x834/0x2330 net/core/dev.c:11952
 unregister_netdevice_many net/core/dev.c:12046 [inline]
 default_device_exit_batch+0x819/0x890 net/core/dev.c:12538
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x7a9/0xbd0 net/core/net_namespace.c:654
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ip_mc_hash_remove net/ipv4/igmp.c:1431 [inline]
RIP: 0010:__ip_mc_dec_group+0x2fd/0x690 net/ipv4/igmp.c:1774
Code: 89 e5 de f7 c6 05 d0 e2 87 05 01 48 c7 c7 c0 88 7a 8c be 97 05 00 00 48 c7 c2 40 89 7a 8c e8 9a 5d bd f7 4c 89 e3 48 c1 eb 03 <42> 80 3c 2b 00 74 08 4c 89 e7 e8 54 da 40 f8 4d 8b 2c 24 4d 39 f5
RSP: 0018:ffffc900036bf4d8 EFLAGS: 00010206
RAX: ffffffff89e0da8e RBX: 000000001fffe1ac RCX: ffff88805d493c00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88805ef23820 R08: ffffffff8f2f41e7 R09: 1ffffffff1e5e83c
R10: dffffc0000000000 R11: fffffbfff1e5e83d R12: 00000000ffff0d60
R13: dffffc0000000000 R14: ffff88807b4c3800 R15: 1ffff1100bde4704
FS:  0000000000000000(0000) GS:ffff8881260cc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055db7747f008 CR3: 000000002efe6000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	89 e5                	mov    %esp,%ebp
   2:	de f7                	fdivp  %st,%st(7)
   4:	c6 05 d0 e2 87 05 01 	movb   $0x1,0x587e2d0(%rip)        # 0x587e2db
   b:	48 c7 c7 c0 88 7a 8c 	mov    $0xffffffff8c7a88c0,%rdi
  12:	be 97 05 00 00       	mov    $0x597,%esi
  17:	48 c7 c2 40 89 7a 8c 	mov    $0xffffffff8c7a8940,%rdx
  1e:	e8 9a 5d bd f7       	call   0xf7bd5dbd
  23:	4c 89 e3             	mov    %r12,%rbx
  26:	48 c1 eb 03          	shr    $0x3,%rbx
* 2a:	42 80 3c 2b 00       	cmpb   $0x0,(%rbx,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 e7             	mov    %r12,%rdi
  34:	e8 54 da 40 f8       	call   0xf840da8d
  39:	4d 8b 2c 24          	mov    (%r12),%r13
  3d:	4d 39 f5             	cmp    %r14,%r13

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/05 21:20 net ebd297a2affa 6ca47dd8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in __ip_mc_dec_group
2025/05/05 18:38 net ebd297a2affa 6ca47dd8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in __ip_mc_dec_group
2025/05/04 20:19 net ebd297a2affa b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in __ip_mc_dec_group
2025/05/04 14:00 net ebd297a2affa b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in __ip_mc_dec_group
* Struck through repros no longer work on HEAD.