syzbot


divide error in taprio_update_queue_max_sdu

Status: upstream: reported on 2024/05/27 13:22
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+233e6e0ea2ba2c86fa79@syzkaller.appspotmail.com
First crash: 23d, last: 23d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [net?] divide error in taprio_update_queue_max_sdu 0 (1) 2024/05/27 13:22

Sample crash report:
Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 15391 Comm: syz-executor.0 Not tainted 6.9.0-syzkaller-08544-g4b377b4868ef #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:div_u64_rem include/linux/math64.h:29 [inline]
RIP: 0010:div_u64 include/linux/math64.h:130 [inline]
RIP: 0010:duration_to_length net/sched/sch_taprio.c:259 [inline]
RIP: 0010:taprio_update_queue_max_sdu+0x287/0x870 net/sched/sch_taprio.c:288
Code: be 08 00 00 00 e8 99 5b 6a f8 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 13 59 6a f8 48 8b 03 89 c1 48 89 e8 31 d2 <48> f7 f1 48 89 c5 48 83 7c 24 50 00 4c 8b 74 24 30 74 47 e8 c1 19
RSP: 0018:ffffc9000506eb38 EFLAGS: 00010246
RAX: 0000000000001f40 RBX: ffff88802f3562e0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88802f3562e0
RBP: 0000000000001f40 R08: ffff88802f3562e7 R09: 1ffff11005e6ac5c
R10: dffffc0000000000 R11: ffffed1005e6ac5d R12: 00000000ffffffff
R13: dffffc0000000000 R14: ffff88801ef59400 R15: 00000000003f0008
FS:  00007fee340bf6c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2c524000 CR3: 0000000024a52000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 taprio_change+0x2dce/0x42d0 net/sched/sch_taprio.c:1911
 taprio_init+0x9da/0xc80 net/sched/sch_taprio.c:2112
 qdisc_create+0x9d4/0x11a0 net/sched/sch_api.c:1355
 tc_modify_qdisc+0xa26/0x1e40 net/sched/sch_api.c:1777
 rtnetlink_rcv_msg+0x89b/0x10d0 net/core/rtnetlink.c:6595
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2564
 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
 netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
 netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
 ___sys_sendmsg net/socket.c:2638 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fee3327cee9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fee340bf0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fee333abf80 RCX: 00007fee3327cee9
RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 000000000000000e
RBP: 00007fee332c949e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fee333abf80 R15: 00007fff3d596598
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:div_u64_rem include/linux/math64.h:29 [inline]
RIP: 0010:div_u64 include/linux/math64.h:130 [inline]
RIP: 0010:duration_to_length net/sched/sch_taprio.c:259 [inline]
RIP: 0010:taprio_update_queue_max_sdu+0x287/0x870 net/sched/sch_taprio.c:288
Code: be 08 00 00 00 e8 99 5b 6a f8 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 13 59 6a f8 48 8b 03 89 c1 48 89 e8 31 d2 <48> f7 f1 48 89 c5 48 83 7c 24 50 00 4c 8b 74 24 30 74 47 e8 c1 19
RSP: 0018:ffffc9000506eb38 EFLAGS: 00010246
RAX: 0000000000001f40 RBX: ffff88802f3562e0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88802f3562e0
RBP: 0000000000001f40 R08: ffff88802f3562e7 R09: 1ffff11005e6ac5c
R10: dffffc0000000000 R11: ffffed1005e6ac5d R12: 00000000ffffffff
R13: dffffc0000000000 R14: ffff88801ef59400 R15: 00000000003f0008
FS:  00007fee340bf6c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31424000 CR3: 0000000024a52000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	be 08 00 00 00       	mov    $0x8,%esi
   5:	e8 99 5b 6a f8       	call   0xf86a5ba3
   a:	48 89 d8             	mov    %rbx,%rax
   d:	48 c1 e8 03          	shr    $0x3,%rax
  11:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  16:	74 08                	je     0x20
  18:	48 89 df             	mov    %rbx,%rdi
  1b:	e8 13 59 6a f8       	call   0xf86a5933
  20:	48 8b 03             	mov    (%rbx),%rax
  23:	89 c1                	mov    %eax,%ecx
  25:	48 89 e8             	mov    %rbp,%rax
  28:	31 d2                	xor    %edx,%edx
* 2a:	48 f7 f1             	div    %rcx <-- trapping instruction
  2d:	48 89 c5             	mov    %rax,%rbp
  30:	48 83 7c 24 50 00    	cmpq   $0x0,0x50(%rsp)
  36:	4c 8b 74 24 30       	mov    0x30(%rsp),%r14
  3b:	74 47                	je     0x84
  3d:	e8                   	.byte 0xe8
  3e:	c1                   	.byte 0xc1
  3f:	19                   	.byte 0x19

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/23 12:01 net-next 4b377b4868ef 4d098039 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce divide error in taprio_update_queue_max_sdu
* Struck through repros no longer work on HEAD.