[v6.1] INFO: rcu detected stall in sys_recvmmsg

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e3a87a10f259 Linux 6.1.21
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12f21741c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=b49b0405a60858ed
dashboard link: https://syzkaller.appspot.com/bug?extid=eaed981d2f84cd2c9188
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed3d1f3e75e6/disk-e3a87a10.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6d8e44c8c75c/vmlinux-e3a87a10.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cebe803ea4fa/bzImage-e3a87a10.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eaed98...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=1b5c/1/0x4000000000000000 softirq=31278/31279 fqs=12
(detected by 1, t=10505 jiffies, g=48837, q=342 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10857 Comm: syz-executor.0 Not tainted 6.1.21-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:advance_sched+0xc2/0x940 net/sched/sch_taprio.c:703
Code: 42 80 3c 30 00 74 08 4c 89 ff e8 29 da 2f f9 49 8b 07 48 89 04 24 e8 4d b1 cd 01 89 c3 31 ff 89 c6 e8 32 be d9 f8 85 db 74 28 <49> 8d 7d c0 be ff ff ff ff e8 c0 ad cd 01 89 c3 31 ff 89 c6 e8 15
RSP: 0018:ffffc90000007cc0 EFLAGS: 00000002
RAX: 0000000080010001 RBX: 0000000000000001 RCX: ffff8880827357c0
RDX: ffff8880827357c0 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88807cf762e8 R08: ffffffff88afcd0e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff88807cf76000
R13: ffff88807cf76340 R14: dffffc0000000000 R15: ffff88807cf76328
FS: 00007f9c71dfe700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000202cb030 CR3: 000000007a0a0000 CR4: 00000000003506f0
Call Trace:
<IRQ>
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x5e5/0xe50 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline]
__sysvec_apic_timer_interrupt+0x156/0x580 arch/x86/kernel/apic/apic.c:1113
sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1107
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:arch_atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline]
RIP: 0010:arch_atomic_long_read include/linux/atomic/atomic-long.h:29 [inline]
RIP: 0010:atomic_long_read include/linux/atomic/atomic-instrumented.h:1266 [inline]
RIP: 0010:__mutex_unlock_slowpath+0xf7/0x750 kernel/locking/mutex.c:916
Code: 24 88 00 00 00 49 8d 7e 68 4c 89 fe e8 f2 9a e3 f6 4c 89 f7 be 08 00 00 00 e8 65 81 59 f7 4c 89 f0 48 c1 e8 03 48 89 44 24 28 <42> 80 3c 28 00 74 08 4c 89 f7 e8 ba 7f 59 f7 49 8b 1e 4d 89 e7 49
RSP: 0018:ffffc9000392f640 EFLAGS: 00000a06
RAX: 1ffff1100fd589a5 RBX: ffffc9000392f6c0 RCX: ffffffff8a86274b
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88807eac4d28
RBP: ffffc9000392f750 R08: dffffc0000000000 R09: ffffed100fd589a6
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc9000392f6e0
R13: dffffc0000000000 R14: ffff88807eac4d28 R15: ffffffff893b592d
__unix_dgram_recvmsg+0xcbd/0x1260 net/unix/af_unix.c:2532
____sys_recvmsg+0x285/0x530
___sys_recvmsg net/socket.c:2743 [inline]
do_recvmmsg+0x46d/0xad0 net/socket.c:2837
__sys_recvmmsg net/socket.c:2916 [inline]
__do_sys_recvmmsg net/socket.c:2939 [inline]
__se_sys_recvmmsg net/socket.c:2932 [inline]
__x64_sys_recvmmsg+0x195/0x240 net/socket.c:2932
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9c7328c0f9
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:00007f9c71dfe168 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f9c733ac050 RCX: 00007f9c7328c0f9
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000005
RBP: 00007f9c732e7b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff349217af R14: 00007f9c71dfe300 R15: 0000000000022000
</TASK>
rcu: rcu_preempt kthread starved for 10465 jiffies! g48837 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:26712 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5238 [inline]
__schedule+0x132c/0x4330 kernel/sched/core.c:6551
schedule+0xbf/0x180 kernel/sched/core.c:6627
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935
rcu_gp_fqs_loop+0x2c2/0x1010 kernel/rcu/tree.c:1660
rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1859
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 3866 Comm: kworker/u4:9 Not tainted 6.1.21-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:413 [inline]
RIP: 0010:smp_call_function_many_cond+0x1f62/0x33d0 kernel/smp.c:987
Code: 2f 44 89 ee 83 e6 01 31 ff e8 ba fe 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 0a e8 45 fb 0a 00 e9 1b ff ff ff f3 90 <42> 0f b6 04 2b 84 c0 75 14 41 f7 07 01 00 00 00 0f 84 fe fe ff ff
RSP: 0018:ffffc90004a675a0 EFLAGS: 00000293
RAX: ffffffff817e8cbd RBX: 1ffff11017308415 RCX: ffff888027e89d40
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004a67980 R08: ffffffff817e8c86 R09: fffffbfff204de31
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000800000000
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b98420a8
FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff77ccd56be CR3: 000000000cc8e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1155
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:1316 [inline]
text_poke_bp_batch+0x2bb/0x940 arch/x86/kernel/alternative.c:1516
text_poke_flush arch/x86/kernel/alternative.c:1707 [inline]
text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1714
arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x12e/0x250 kernel/jump_label.c:177
static_key_enable+0x16/0x20 kernel/jump_label.c:190
toggle_allocation_gate+0xbf/0x480 mm/kfence/core.c:800
process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.