syzbot


BUG: soft lockup in tx
Status: fixed on 2021/10/04 07:44
Reported-by: syzbot+b9869786f84bfb6fa7f3@syzkaller.appspotmail.com
Fix commit: 7c113506163a fq_codel: reject silly quantum parameters
First crash: 292d, last: 262d

Fix bisection: fixed by (bisect log) :
commit 7c113506163a1ec6157927428eddd80038d2916e
Author: Eric Dumazet <edumazet@google.com>
Date: Fri Sep 3 22:03:43 2021 +0000

  fq_codel: reject silly quantum parameters

similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 BUG: soft lockup in tx C error 2 47d 226d 0/1 upstream: reported C repro on 2021/10/09 08:02
upstream INFO: rcu detected stall in tx C error unreliable 3 261d 399d 22/22 fixed on 2021/11/10 00:50
upstream INFO: rcu detected stall in tx (2) 79 27d 146d 0/22 upstream: reported on 2021/12/28 12:52

Sample crash report:
watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [aoe_tx0:3131]
Modules linked in:
irq event stamp: 15707
hardirqs last  enabled at (15706): [<ffffffff81003ce4>] trace_hardirqs_on_thunk+0x1a/0x1c
hardirqs last disabled at (15707): [<ffffffff81003d00>] trace_hardirqs_off_thunk+0x1a/0x1c
softirqs last  enabled at (794): [<ffffffff86765b45>] rcu_read_unlock_bh include/linux/rcupdate.h:717 [inline]
softirqs last  enabled at (794): [<ffffffff86765b45>] __dev_queue_xmit+0x15f5/0x2e00 net/core/dev.c:3865
softirqs last disabled at (804): [<ffffffff86764732>] __dev_queue_xmit+0x1e2/0x2e00 net/core/dev.c:3773
CPU: 1 PID: 3131 Comm: aoe_tx0 Not tainted 4.19.200-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:fq_codel_dequeue+0xf8/0x3740 net/sched/sch_fq_codel.c:302
Code: 74 24 40 49 8b 87 e8 02 00 00 48 89 74 24 08 48 39 c6 0f 84 b8 08 00 00 e8 35 a4 ca fa 48 8b 44 24 08 48 c1 e8 03 80 3c 18 00 <0f> 85 60 2d 00 00 48 8b 44 24 08 4c 8b 30 49 8d 46 10 48 89 84 24
RSP: 0018:ffff8880ab237a20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffff11016271b2f RBX: dffffc0000000000 RCX: ffffffff8697e83a
RDX: 0000000000000000 RSI: ffffffff8697de5b RDI: ffff888091b4de18
RBP: ffff8880b138d980 R08: 000000009c5b1aa3 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff8c66305b R12: 0000000000000001
R13: ffff8880b138d978 R14: ffff888091b4de10 R15: ffff8880b138d680
FS:  0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b11d0 CR3: 0000000009e6d000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 dequeue_skb net/sched/sch_generic.c:282 [inline]
 qdisc_restart net/sched/sch_generic.c:385 [inline]
 __qdisc_run+0x1b9/0x1640 net/sched/sch_generic.c:403
 __dev_xmit_skb net/core/dev.c:3500 [inline]
 __dev_queue_xmit+0x1518/0x2e00 net/core/dev.c:3807
 tx+0x68/0xb0 drivers/block/aoe/aoenet.c:63
 kthread+0x1d9/0x390 drivers/block/aoe/aoecmd.c:1241
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2021/08/04 09:42 linux-4.19.y 53bd76690e27 6c236867 .config log report syz C BUG: soft lockup in tx