syzbot


BUG: soft lockup in __do_softirq

Status: upstream: reported syz repro on 2021/03/23 20:32
Reported-by: syzbot+70cbd1b4257a8631183e@syzkaller.appspotmail.com
First crash: 624d, last: 582d

Fix bisection: failed (bisect log)
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in __do_softirq syz done 34 425d 1221d 0/24 upstream: reported syz repro on 2019/08/05 15:28
Patch testing requests:
Created Duration User Patch Repo Result
2022/09/17 00:29 11m retest repro linux-4.14.y report log
2022/09/16 23:29 11m retest repro linux-4.14.y report log

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 35s! [syz-executor.2:29113]
Modules linked in:
irq event stamp: 50673245
hardirqs last  enabled at (50673244): [<ffffffff87400976>] restore_regs_and_return_to_kernel+0x0/0x2a
hardirqs last disabled at (50673245): [<ffffffff874018ae>] apic_timer_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:793
softirqs last  enabled at (546): [<ffffffff85c0d0f0>] spin_unlock_bh include/linux/spinlock.h:362 [inline]
softirqs last  enabled at (546): [<ffffffff85c0d0f0>] peernet2id+0x60/0x70 net/core/net_namespace.c:245
softirqs last disabled at (50673241): [<ffffffff81320c83>] invoke_softirq kernel/softirq.c:368 [inline]
softirqs last disabled at (50673241): [<ffffffff81320c83>] irq_exit+0x193/0x240 kernel/softirq.c:409
CPU: 0 PID: 29113 Comm: syz-executor.2 Not tainted 4.14.231-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888094f6a000 task.stack: ffff8880b44b0000
RIP: 0010:ffs arch/x86/include/asm/bitops.h:427 [inline]
RIP: 0010:__do_softirq+0x215/0x9ff kernel/softirq.c:276
RSP: 0018:ffff8880ba407f30 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff11e125b RBX: ffff888094f6a000 RCX: 1ffff110129ed515
RDX: 0000000000000000 RSI: ffff888094f6a8b0 RDI: ffff888094f6a884
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000000b1
R13: 00000000000000b1 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007faef42e1700(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000a6ebd000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 invoke_softirq kernel/softirq.c:368 [inline]
 irq_exit+0x193/0x240 kernel/softirq.c:409
 exiting_irq arch/x86/include/asm/apic.h:638 [inline]
 do_IRQ+0x112/0x1d0 arch/x86/kernel/irq.c:242
 common_interrupt+0x93/0x93 arch/x86/entry/entry_64.S:576
 </IRQ>
RIP: 0010:kvm_cpu_has_injectable_intr+0x2/0x2c0 arch/x86/kvm/irq.c:75
RSP: 0018:ffff8880b44b7ae0 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff4e
RAX: ffff888094f6a000 RBX: 0000000000000000 RCX: ffff8880b30d4d84
RDX: 0000000000000000 RSI: ffff8880b30d0d9c RDI: ffff8880b30d0980
RBP: ffff8880b44b7c40 R08: 0000000000000000 R09: 000000000002062a
R10: ffff888094f6a8b0 R11: ffff888094f6a000 R12: ffff8880b30d4d89
R13: ffff8880b30d09b0 R14: dffffc0000000000 R15: ffff8880b30d0980
 vcpu_enter_guest arch/x86/kvm/x86.c:7156 [inline]
 vcpu_run arch/x86/kvm/x86.c:7364 [inline]
 kvm_arch_vcpu_ioctl_run+0x26da/0x5ae0 arch/x86/kvm/x86.c:7531
 kvm_vcpu_ioctl+0x3de/0xc50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2661
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x4665f9
RSP: 002b:00007faef42e1188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 00000000004665f9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00000000004bfbb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008
R13: 00007ffd019ae02f R14: 00007faef42e1300 R15: 0000000000022000
Code: 48 c7 c0 d8 92 f0 88 48 c1 e8 03 42 80 3c 38 00 0f 85 38 07 00 00 48 83 3d d0 90 90 01 00 0f 84 8e 06 00 00 fb 66 0f 1f 44 00 00 <b8> ff ff ff ff 48 c7 c3 c0 90 e0 88 0f bc 44 24 04 89 c6 83 c6 
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5 Comm: kworker/u4:0 Not tainted 4.14.231-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-8:0)
task: ffff8880b5ff2140 task.stack: ffff8880b5ff8000
RIP: 0010:__sanitizer_cov_trace_pc+0x23/0x50 kernel/kcov.c:68
RSP: 0018:ffff8880b5ffee98 EFLAGS: 00000246
RAX: ffff8880b5ff2140 RBX: 1ffff11016bffdd8 RCX: 1ffff11016bfe556
RDX: 0000000000000000 RSI: ffff8880b5ff2a90 RDI: 0000000000000286
RBP: ffff8880b5ffef50 R08: ffffffff8b9aa988 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8880b5fff008 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f1ce1ad168 CR3: 0000000008e6a000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rep_nop arch/x86/include/asm/processor.h:646 [inline]
 cpu_relax arch/x86/include/asm/processor.h:651 [inline]
 csd_lock_wait kernel/smp.c:108 [inline]
 smp_call_function_single+0x17f/0x370 kernel/smp.c:302
 smp_call_function_many+0x60f/0x7a0 kernel/smp.c:434
 flush_tlb_others arch/x86/include/asm/paravirt.h:309 [inline]
 flush_tlb_mm_range+0x158/0x2f0 arch/x86/mm/tlb.c:709
 flush_tlb_page arch/x86/include/asm/tlbflush.h:573 [inline]
 ptep_clear_flush+0xde/0x110 mm/pgtable-generic.c:87
 page_mkclean_one+0x237/0x540 mm/rmap.c:915
 rmap_walk_file+0x37c/0x810 mm/rmap.c:1829
 rmap_walk+0xc4/0x150 mm/rmap.c:1847
 page_mkclean+0x148/0x180 mm/rmap.c:981
 clear_page_dirty_for_io+0x1a6/0xb80 mm/page-writeback.c:2704
 mpage_submit_page+0x6e/0x220 fs/ext4/inode.c:2214
 mpage_process_page_bufs+0x425/0x520 fs/ext4/inode.c:2344
 mpage_prepare_extent_to_map+0x43e/0xa10 fs/ext4/inode.c:2716
 ext4_writepages+0xf88/0x32a0 fs/ext4/inode.c:2863
 do_writepages+0xc3/0x240 mm/page-writeback.c:2361
 __writeback_single_inode+0xda/0x1010 fs/fs-writeback.c:1377
 writeback_sb_inodes+0x48b/0xd30 fs/fs-writeback.c:1639
 __writeback_inodes_wb+0xbf/0x230 fs/fs-writeback.c:1708
 wb_writeback+0x710/0xb80 fs/fs-writeback.c:1814
 wb_check_old_data_flush fs/fs-writeback.c:1927 [inline]
 wb_do_writeback fs/fs-writeback.c:1951 [inline]
 wb_workfn+0x708/0xf50 fs/fs-writeback.c:1980
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 90 90 90 90 90 90 90 90 65 48 8b 04 25 80 df 01 00 48 85 c0 74 1a 65 8b 15 8b b9 ac 7e 81 e2 00 01 1f 00 75 0b 8b 90 58 13 00 00 <83> fa 01 74 01 c3 48 8b 34 24 48 8b 88 60 13 00 00 8b 80 5c 13 

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2021/04/26 05:43 linux-4.14.y cf256fbcbe34 2a82f1b3 .config log report syz BUG: soft lockup in __do_softirq
ci2-linux-4-14 2021/03/23 20:32 linux-4.14.y cb83ddcd5332 e613994b .config log report syz BUG: soft lockup in __do_softirq
ci2-linux-4-14 2021/05/04 22:11 linux-4.14.y 7d7d1c0ab3eb 06c27ff5 .config log report info BUG: soft lockup in __do_softirq
* Struck through repros no longer work on HEAD.