linux-kernel - Re: [syzbot] [bpf?] [mm?] INFO: rcu detected stall in sys

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Message-ID: <000000000000244dcc061c53341e@google.com>
Date: Wed, 03 Jul 2024 00:59:02 -0700
From: syzbot <syzbot+c4c6c3dc10cc96bcf723@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, radoslaw.zielonek@...il.com, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bpf?] [mm?] INFO: rcu detected stall in sys_clone (8)

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: rcu detected stall in pipe_write

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-...D } 2685 jiffies s: 1749 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5372 Comm: syz-executor.0 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:32 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:67 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:103 [inline]
RIP: 0010:lock_acquire+0x17e/0x530 kernel/locking/lockdep.c:5750
Code: 4c 89 fb 48 c1 eb 03 42 80 3c 2b 00 74 08 4c 89 ff e8 d6 a7 86 00 48 c7 84 24 80 00 00 00 00 00 00 00 9c 8f 84 24 80 00 00 00 <42> 80 3c 2b 00 74 08 4c 89 ff e8 c3 a6 86 00 48 8d 5c 24 60 4c 8b
RSP: 0018:ffffc90000007b20 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 1ffff92000000f74 RCX: ffffffff8171b8f4
RDX: 0000000000000000 RSI: ffffffff8bfec3a0 RDI: ffffffff8bfec360
RBP: ffffc90000007c68 R08: ffffffff8f8638ef R09: 1ffffffff1f0c71d
R10: dffffc0000000000 R11: fffffbfff1f0c71e R12: 1ffff92000000f6c
R13: dffffc0000000000 R14: 0000000000000000 R15: ffffc90000007ba0
FS:  0000555559d06480(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0000ab000 CR3: 000000004ddde000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 advance_sched+0xab/0xca0 net/sched/sch_taprio.c:924
 __run_hrtimer kernel/time/hrtimer.c:1692 [inline]
 __hrtimer_run_queues+0x595/0xd00 kernel/time/hrtimer.c:1756
 hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1818
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline]
 __sysvec_apic_timer_interrupt+0x107/0x3a0 arch/x86/kernel/apic/apic.c:1049
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5284
Code: c9 50 e8 c9 cc 0b 00 48 83 c4 08 4c 89 f7 e8 1d 38 00 00 0f 1f 44 00 00 4c 89 f7 e8 b0 ec 13 0a e8 db 58 36 00 fb 48 8b 5d c0 <48> 8d bb f0 15 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc
RSP: 0018:ffffc90004d9f608 EFLAGS: 00000286
RAX: 0cc8c24fa40d4e00 RBX: ffff88807b770000 RCX: ffffffff944ba603
RDX: dffffc0000000000 RSI: ffffffff8baac1e0 RDI: ffffffff8bfec3c0
RBP: ffffc90004d9f650 R08: ffffffff8f8638ef R09: 1ffffffff1f0c71d
R10: dffffc0000000000 R11: fffffbfff1f0c71e R12: 1ffff11017287e17
R13: dffffc0000000000 R14: ffff8880b943e340 R15: ffff8880b943f0b8
 context_switch kernel/sched/core.c:5413 [inline]
 __schedule+0x17db/0x4a20 kernel/sched/core.c:6737
 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6916
 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6940
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:12
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0x130/0x140 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __wake_up_common_lock+0x18c/0x1e0 kernel/sched/wait.c:108
 pipe_write+0x128d/0x1a40 fs/pipe.c:602
 call_write_iter include/linux/fs.h:2108 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa84/0xcb0 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f1049e7cbef
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 b9 80 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 0c 81 02 00 48
RSP: 002b:00007ffd35cde690 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f1049e7cbef
RDX: 000000000000000c RSI: 00007ffd35cde780 RDI: 00000000000000f8
RBP: 00007ffd35cde71c R08: 0000000000000000 R09: 00007f104ab390b0
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000032
R13: 0000000000017c34 R14: 0000000000017c2c R15: 0000000000000004
 </TASK>


Tested on:

commit:         fe46a7dd Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12b491be980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2bf01fac005fe0a9
dashboard link: https://syzkaller.appspot.com/bug?extid=c4c6c3dc10cc96bcf723
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12de23c6980000