BUG: soft lockup in proc_sys_call_handler

Status: upstream: reported on 2023/01/21 03:02
Reported-by: syzbot+c0007588fc571c2b99e8@syzkaller.appspotmail.com
First crash: 1304d, last: 1304d
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in proc_sys_call_handler (2) fs 1 4 499d 702d 0/29 auto-obsoleted due to no activity on 2025/07/04 12:08
upstream INFO: rcu detected stall in proc_sys_call_handler kernel 1 1 1528d 1528d 0/29 auto-closed as invalid on 2022/09/09 16:54

Sample crash report:
syz-executor.2 (28609): drop_caches: 2
watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [syz-executor.4:28614]
Modules linked in:
irq event stamp: 2365622
hardirqs last  enabled at (2365621): [<ffffffff81003ce4>] trace_hardirqs_on_thunk+0x1a/0x1c
hardirqs last disabled at (2365622): [<ffffffff81003d00>] trace_hardirqs_off_thunk+0x1a/0x1c
softirqs last  enabled at (33508): [<ffffffff88400678>] __do_softirq+0x678/0x980 kernel/softirq.c:318
softirqs last disabled at (32613): [<ffffffff813927d5>] invoke_softirq kernel/softirq.c:372 [inline]
softirqs last disabled at (32613): [<ffffffff813927d5>] irq_exit+0x215/0x260 kernel/softirq.c:412
CPU: 0 PID: 28614 Comm: syz-executor.4 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:435 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x3a6/0xae0 kernel/locking/qspinlock.c:474
Code: eb c6 45 01 01 41 bc 00 80 00 00 48 c1 e9 03 83 e3 07 41 be 01 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 2c 01 eb 0c f3 90 <41> 83 ec 01 0f 84 38 04 00 00 41 0f b6 45 00 38 d8 7f 08 84 c0 0f
RSP: 0018:ffff88808d1c72d8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000003 RBX: 0000000000000000 RCX: 1ffff110148f6ad0
RDX: 0000000000000001 RSI: ffffffff8167a995 RDI: 0000000000000286
RBP: ffff8880a47b5680 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000007f3b
R13: ffffed10148f6ad0 R14: 0000000000000001 R15: ffff8880ba02be00
FS:  00007f59194d6700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3062e000 CR3: 000000009d9fd000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:679 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:53 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:88 [inline]
 do_raw_spin_lock+0x189/0x220 kernel/locking/spinlock_debug.c:113
 spin_lock include/linux/spinlock.h:329 [inline]
 list_lru_walk_one+0x4b/0xd0 mm/list_lru.c:273
 list_lru_shrink_walk include/linux/list_lru.h:195 [inline]
 prune_dcache_sb+0xdc/0x140 fs/dcache.c:1171
 super_cache_scan+0x339/0x590 fs/super.c:102
 do_shrink_slab+0x397/0xa40 mm/vmscan.c:537
 shrink_slab+0x16f/0x550 mm/vmscan.c:693
 drop_slab_node+0x33/0x70 mm/vmscan.c:724
 drop_slab+0x4b/0x90 mm/vmscan.c:734
 drop_caches_sysctl_handler+0xf6/0x110 fs/drop_caches.c:65
 proc_sys_call_handler.isra.0+0x1f3/0x3b0 fs/proc/proc_sysctl.c:597
 __vfs_write+0xf7/0x770 fs/read_write.c:485
 __kernel_write+0x109/0x370 fs/read_write.c:506
 write_pipe_buf+0x153/0x1f0 fs/splice.c:798
 splice_from_pipe_feed fs/splice.c:503 [inline]
 __splice_from_pipe+0x389/0x800 fs/splice.c:627
 splice_from_pipe fs/splice.c:662 [inline]
 default_file_splice_write+0xd8/0x180 fs/splice.c:810
 do_splice_from fs/splice.c:852 [inline]
 direct_splice_actor+0x115/0x160 fs/splice.c:1025
 splice_direct_to_actor+0x33f/0x8d0 fs/splice.c:980
 do_splice_direct+0x1a7/0x270 fs/splice.c:1068
 do_sendfile+0x550/0xc30 fs/read_write.c:1447
 __do_sys_sendfile64 fs/read_write.c:1502 [inline]
 __se_sys_sendfile64+0xc4/0x160 fs/read_write.c:1494
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f591af640c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f59194d6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f591b083f80 RCX: 00007f591af640c9
RDX: 0000000020002080 RSI: 0000000000000007 RDI: 0000000000000008
RBP: 00007f591afbfae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000870 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe311493af R14: 00007f59194d6300 R15: 0000000000022000
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 28609 Comm: syz-executor.2 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
RIP: 0010:__lock_acquire+0x7/0x3ff0 kernel/locking/lockdep.c:3275
Code: e8 0e 6a 4d 00 8b 34 24 e9 5f ff ff ff 48 89 34 24 e8 3d 68 4d 00 48 8b 34 24 eb a5 0f 1f 80 00 00 00 00 41 57 45 89 c7 41 56 <49> 89 fe 41 55 41 54 45 89 cc 55 89 cd 53 89 d3 48 ba 00 00 00 00
RSP: 0018:ffff8880ba107d68 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff88809f48a300 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880ba124cd8
RBP: ffff8880ba124cd8 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS:  00007fed7566d700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30623000 CR3: 000000005b70c000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:152
 lock_hrtimer_base kernel/time/hrtimer.c:174 [inline]
 hrtimer_start_range_ns+0xe6/0xd60 kernel/time/hrtimer.c:1180
 hrtimer_start include/linux/hrtimer.h:398 [inline]
 tasklet_hrtimer_start include/linux/interrupt.h:641 [inline]
 mac80211_hwsim_beacon+0x14b/0x190 drivers/net/wireless/mac80211_hwsim.c:1627
 __tasklet_hrtimer_trampoline+0x29/0xa0 kernel/softirq.c:601
 tasklet_action_common.constprop.0+0x265/0x360 kernel/softirq.c:522
 __do_softirq+0x265/0x980 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x215/0x260 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
 </IRQ>
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:97 [inline]
RIP: 0010:do_raw_spin_unlock+0x3d/0x230 kernel/locking/spinlock_debug.c:134
Code: 83 c7 04 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 bc 01 00 00 81 7d 04 ad 4e ad de <0f> 85 74 01 00 00 be 04 00 00 00 48 89 ef e8 a0 6d 4c 00 48 89 ea
RSP: 0018:ffff88808ea872e8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: 0000000000480004 RCX: 1ffff11013e91585
RDX: 0000000000000000 RSI: 0000000000000005 RDI: ffff88809a20dd64
RBP: ffff88809a20dd60 R08: 0000000034de5ccb R09: 0000000000000004
R10: 0000000000000000 R11: ffff8880b59f68c0 R12: ffff8880a47b56b8
R13: 0000000000000002 R14: ffff88809a20dd60 R15: ffff88809a20dce0
 __raw_spin_unlock include/linux/spinlock_api_smp.h:151 [inline]
 _raw_spin_unlock+0x1f/0x40 kernel/locking/spinlock.c:176
 spin_unlock include/linux/spinlock.h:369 [inline]
 dentry_lru_isolate+0x118/0x1c0 fs/dcache.c:1124
 __list_lru_walk_one+0x182/0x5d0 mm/list_lru.c:230
 list_lru_walk_one+0x99/0xd0 mm/list_lru.c:274
 list_lru_shrink_walk include/linux/list_lru.h:195 [inline]
 prune_dcache_sb+0xdc/0x140 fs/dcache.c:1171
 super_cache_scan+0x339/0x590 fs/super.c:102
 do_shrink_slab+0x397/0xa40 mm/vmscan.c:537
 shrink_slab+0x16f/0x550 mm/vmscan.c:693
 drop_slab_node+0x33/0x70 mm/vmscan.c:724
 drop_slab+0x4b/0x90 mm/vmscan.c:734
 drop_caches_sysctl_handler+0xf6/0x110 fs/drop_caches.c:65
 proc_sys_call_handler.isra.0+0x1f3/0x3b0 fs/proc/proc_sysctl.c:597
 __vfs_write+0xf7/0x770 fs/read_write.c:485
 __kernel_write+0x109/0x370 fs/read_write.c:506
 write_pipe_buf+0x153/0x1f0 fs/splice.c:798
 splice_from_pipe_feed fs/splice.c:503 [inline]
 __splice_from_pipe+0x389/0x800 fs/splice.c:627
 splice_from_pipe fs/splice.c:662 [inline]
 default_file_splice_write+0xd8/0x180 fs/splice.c:810
 do_splice_from fs/splice.c:852 [inline]
 direct_splice_actor+0x115/0x160 fs/splice.c:1025
 splice_direct_to_actor+0x33f/0x8d0 fs/splice.c:980
 do_splice_direct+0x1a7/0x270 fs/splice.c:1068
 do_sendfile+0x550/0xc30 fs/read_write.c:1447
 __do_sys_sendfile64 fs/read_write.c:1502 [inline]
 __se_sys_sendfile64+0xc4/0x160 fs/read_write.c:1494
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fed770fb0c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed7566d168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fed7721af80 RCX: 00007fed770fb0c9
RDX: 0000000020002080 RSI: 0000000000000007 RDI: 0000000000000008
RBP: 00007fed77156ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000870 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe7a7afb3f R14: 00007fed7566d300 R15: 0000000000022000

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/01/21 03:01 linux-4.19.y 3f8a27f9e27b cc0f9968 .config console log report info [disk image] [vmlinux] ci2-linux-4-19 BUG: soft lockup in proc_sys_call_handler
* Struck through repros no longer work on HEAD.