Subject: [syzbot] [net?] INFO: rcu detected stall in sock_write_iter (3)

From: syzbot <[email-masked]>
Date: Tue, 07 May 2024 05:14:17 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    7367539ad4b0 Merge tag 'cxl-fixes-6.9-rc7' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17058250980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3714fc09f933e505
dashboard link: https://syzkaller.appspot.com/bug?extid=2b5fbaaa4280010beda7
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17d9f62f180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1379d9df180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/367ccce69d37/disk-7367539a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/88c894cbcc3a/vmlinux-7367539a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f67d1fb31d1a/bzImage-7367539a.xz

The issue was bisected to:

commit a3d43c0d56f1b94e74963a2fbadfb70126d92213
Author: Vinicius Costa Gomes <[email-masked]>
Date:   Mon Apr 29 22:48:31 2019 +0000

    taprio: Add support adding an admin schedule

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=16f11ea8980000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=15f11ea8980000
console output: https://syzkaller.appspot.com/x/log.txt?x=11f11ea8980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]
Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule")

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=b9c4/1/0x4000000000000000 softirq=6260/6262 fqs=4
rcu: 	(detected by 0, t=10502 jiffies, g=7333, q=68 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5118 Comm: sshd Not tainted 6.9.0-rc6-syzkaller-00234-g7367539ad4b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:__kasan_check_write+0x0/0x20 mm/kasan/shadow.c:36
Code: 48 8b 0c 24 31 d2 e9 6f e6 ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 89 f6 48 8b 0c 24 ba 01 00 00 00 e9 3c e6 ff ff 66 2e
RSP: 0018:ffffc90000a08b98 EFLAGS: 00000097
RAX: 0000000000000004 RBX: dffffc0000000000 RCX: 0000000000a08c03
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffff88807105d2e8
RBP: ffffc90000a08c80 R08: ffffffff92f355e7 R09: 1ffffffff25e6abc
R10: dffffc0000000000 R11: fffffbfff25e6abd R12: ffff88807105d2e8
R13: 1ffff92000141180 R14: ffffc90000a08c00 R15: 1ffff1100e20ba5e
FS:  00007f65e68af800(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc197ad018 CR3: 00000000573a0000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1300 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
 do_raw_spin_lock+0x142/0x370 kernel/locking/spinlock_debug.c:116
 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+0x5a7/0xd50 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+0x112/0x3f0 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:__rcu_read_lock+0x5/0xb0 kernel/rcu/tree_plugin.h:401
Code: fc ff ff e9 62 fc ff ff e8 48 32 03 0a 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 4c 8b 3c 25 c0 d3
RSP: 0018:ffffc900031f7110 EFLAGS: 00000293
RAX: ffffffff89deccd2 RBX: 0000000000000000 RCX: ffff888029465a00
RDX: 0000000000000000 RSI: ffffffff94aecb00 RDI: 0000000000000004
RBP: ffffc900031f7238 R08: 0000000000000000 R09: ffff888021edc000
R10: dffffc0000000000 R11: fffffbfff1f51f6e R12: 1ffff9200063ee2c
R13: ffffffff94aecb00 R14: ffff888022470ff0 R15: dffffc0000000000
 rcu_read_lock include/linux/rcupdate.h:779 [inline]
 nf_hook+0x97/0x450 include/linux/netfilter.h:238
 NF_HOOK_COND include/linux/netfilter.h:302 [inline]
 ip_output+0x185/0x230 net/ipv4/ip_output.c:433
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 __ip_queue_xmit+0x118c/0x1b70 net/ipv4/ip_output.c:535
 __tcp_transmit_skb+0x2557/0x3b80 net/ipv4/tcp_output.c:1462
 tcp_transmit_skb net/ipv4/tcp_output.c:1480 [inline]
 tcp_write_xmit+0x1445/0x6100 net/ipv4/tcp_output.c:2792
 __tcp_push_pending_frames+0x9b/0x360 net/ipv4/tcp_output.c:2977
 tcp_sendmsg_locked+0x42cc/0x4d00 net/ipv4/tcp.c:1310
 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1342
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x1a6/0x270 net/socket.c:745
 sock_write_iter+0x2dd/0x400 net/socket.c:1160
 call_write_iter include/linux/fs.h:2110 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa86/0xcb0 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f65e6516bf2
Code: 89 c7 48 89 44 24 08 e8 7b 34 fa ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6f 48 8b 15 07 a2 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffd643a9c18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000034 RCX: 00007f65e6516bf2
RDX: 0000000000000034 RSI: 000056509ca5f960 RDI: 0000000000000004
RBP: 000056509ca6d220 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000056508b938aa4
R13: 0000000000000276 R14: 000056508b9393e8 R15: 00007ffd643a9c88
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 3.166 msecs
rcu: rcu_preempt kthread starved for 10494 jiffies! g7333 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:25880 pid:16    tgid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5409 [inline]
 __schedule+0x17e8/0x4a50 kernel/sched/core.c:6746
 __schedule_loop kernel/sched/core.c:6823 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6838
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2582
 rcu_gp_fqs_loop+0x2df/0x1370 kernel/rcu/tree.c:1663
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1862
 kthread+0x2f2/0x390 kernel/kthread.c:388
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 5136 Comm: kworker/u8:1 Not tainted 6.9.0-rc6-syzkaller-00234-g7367539ad4b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0x1899/0x2a00 kernel/smp.c:855
Code: 89 e6 83 e6 01 31 ff e8 15 db 0b 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 c0 d6 0b 00 eb 38 f3 90 42 0f b6 04 23 <84> c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 a4 d6 0b 00 eb e4 44
RSP: 0018:ffffc90004b1f6e0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff110172a8869 RCX: ffff8880295c9e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004b1f8e0 R08: ffffffff818a39eb R09: 1ffffffff25e6aa0
R10: dffffc0000000000 R11: fffffbfff25e6aa1 R12: dffffc0000000000
R13: ffff8880b9544348 R14: ffff8880b943f7c0 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5fa233e120 CR3: 000000000e134000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2086 [inline]
 text_poke_bp_batch+0x352/0xb30 arch/x86/kernel/alternative.c:2296
 text_poke_flush arch/x86/kernel/alternative.c:2487 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2494
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x136/0x260 kernel/jump_label.c:205
 static_key_enable+0x1a/0x20 kernel/jump_label.c:218
 toggle_allocation_gate+0xb5/0x250 mm/kfence/core.c:826
 process_one_work kernel/workqueue.c:3267 [inline]
 process_scheduled_works+0xa12/0x17c0 kernel/workqueue.c:3348
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3429
 kthread+0x2f2/0x390 kernel/kthread.c:388
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

---
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