[syzbot] [net?] INFO: rcu detected stall in sys_socket (10)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 18d46e76d7c2 Merge tag 'for-6.7-rc3-tag' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16bcc8b4e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=bb39fe85d254f638
dashboard link: https://syzkaller.appspot.com/bug?extid=de8e83db70e8beedd556
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12172952e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1086b58ae80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0ce5608c89e8/disk-18d46e76.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/eef847faba9c/vmlinux-18d46e76.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6a3df3288860/bzImage-18d46e76.xz

The issue was bisected to:

commit 5a781ccbd19e4664babcbe4b4ead7aa2b9283d22
Author: Vinicius Costa Gomes <viniciu...@intel.com>
Date: Sat Sep 29 00:59:43 2018 +0000

tc: Add support for configuring the taprio scheduler

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16a29b52e80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=15a29b52e80000
console output: https://syzkaller.appspot.com/x/log.txt?x=11a29b52e80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+de8e83...@syzkaller.appspotmail.com
Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler")

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=79f4/1/0x4000000000000000 softirq=5546/5548 fqs=1
rcu: (detected by 1, t=10503 jiffies, g=5017, q=384 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5106 Comm: syz-executor201 Not tainted 6.7.0-rc3-syzkaller-00024-g18d46e76d7c2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1686 [inline]
RIP: 0010:__hrtimer_run_queues+0x62e/0xc20 kernel/time/hrtimer.c:1752
Code: fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 fb 04 00 00 45 0f b6 6e 3b 31 ff 44 89 ee <e8> 2d 46 11 00 45 84 ed 0f 84 8e fb ff ff e8 ef 4a 11 00 4c 89 f7
RSP: 0018:ffffc90000007e40 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8880b982ba40 RCX: ffffffff817642f9
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000002 R12: ffff8880b982b940
R13: 0000000000000000 R14: ffff88801c43a340 R15: ffffffff88a2daf0
FS: 00005555566fe380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe9404c73b0 CR3: 0000000076e2d000 CR4: 0000000000350ef0
Call Trace:
<NMI>
</NMI>
<IRQ>
hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1065 [inline]
__sysvec_apic_timer_interrupt+0x105/0x400 arch/x86/kernel/apic/apic.c:1082
sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1076
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:lock_acquire+0x1ef/0x520 kernel/locking/lockdep.c:5722
Code: c1 05 bd 6c 9a 7e 83 f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24
RSP: 0018:ffffc9000432fb00 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff92000865f62 RCX: ffffffff81672c0e
RDX: 0000000000000001 RSI: ffffffff8accbae0 RDI: ffffffff8b2f0dc0
RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff23e33d0
R10: ffffffff91f19e87 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffffffff8d0f0b48 R15: 0000000000000000
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x175/0x9d0 kernel/locking/mutex.c:747
pcpu_alloc+0xbb8/0x1420 mm/percpu.c:1769
packet_alloc_pending net/packet/af_packet.c:1232 [inline]
packet_create+0x2b7/0x8e0 net/packet/af_packet.c:3373
__sock_create+0x328/0x800 net/socket.c:1569
sock_create net/socket.c:1620 [inline]
__sys_socket_create net/socket.c:1657 [inline]
__sys_socket+0x14c/0x260 net/socket.c:1704
__do_sys_socket net/socket.c:1718 [inline]
__se_sys_socket net/socket.c:1716 [inline]
__x64_sys_socket+0x72/0xb0 net/socket.c:1716
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fe940479de9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 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:00007ffe1bf080b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe940479de9
RDX: 0000000000000000 RSI: 0000000800000003 RDI: 0000000000000011
RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000100000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe1bf08110
R13: 0000000000030c67 R14: 00007ffe1bf080dc R15: 0000000000000003
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.067 msecs
rcu: rcu_preempt kthread timer wakeup didn't happen for 10497 jiffies! g5017 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=2416
rcu: rcu_preempt kthread starved for 10498 jiffies! g5017 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27904 pid:17 tgid:17 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5376 [inline]
__schedule+0xedb/0x5af0 kernel/sched/core.c:6688
__schedule_loop kernel/sched/core.c:6763 [inline]
schedule+0xe9/0x270 kernel/sched/core.c:6778
schedule_timeout+0x137/0x290 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x1ec/0xb10 kernel/rcu/tree.c:1631
rcu_gp_kthread+0x24b/0x380 kernel/rcu/tree.c:1830
kthread+0x2c6/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
</TASK>


---
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If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

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#syz test: git://repo/address.git branch-or-commit-hash
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[Edward Adam Davis]

please test rcu detected stall in sys_socket

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 18d46e76d7c2

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 31a8252bd09c..4bc377120ea0 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -843,6 +843,7 @@ static struct sk_buff *taprio_dequeue(struct Qdisc *sch)

rcu_read_lock();
entry = rcu_dereference(q->current_entry);
+ rcu_read_unlock();
/* if there's no entry, it means that the schedule didn't
* start yet, so force all gates to be open, this is in
* accordance to IEEE 802.1Qbv-2015 Section 8.6.9.4.5
@@ -869,8 +870,6 @@ static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
}

done:
- rcu_read_unlock();
-
return skb;
}

[syzbot]

Hello,

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

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-...D } 2651 jiffies s: 2425 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5512 Comm: sed Not tainted 6.7.0-rc3-syzkaller-00024-g18d46e76d7c2-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023

RIP: 0010:__lock_acquire+0xc89/0x3b20 kernel/locking/lockdep.c:5134
Code: e7 e8 eb 52 ff ff 48 ba 00 00 00 00 00 fc ff df 48 8d 78 40 48 89 f9 48 c1 e9 03 80 3c 11 00 0f 85 98 2b 00 00 48 83 78 40 00 <0f> 84 7c 13 00 00 0f b7 44 24 08 8b 5c 24 48 8b 4c 24 20 c1 e0 0d
RSP: 0018:ffffc900001f0b40 EFLAGS: 00000082
RAX: ffffffff91f8d970 RBX: 0000000000000000 RCX: 1ffffffff23f1b36
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffffff91f8d9b0
RBP: ffffffff91f1bca0 R08: 0000000000000000 R09: fffffbfff23e33f3
R10: ffffffff91f19f9f R11: 0000000000000002 R12: ffff888025676450
R13: ffff888025676449 R14: 00000000000008e1 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f588bec5ba8 CR3: 0000000029d0e000 CR4: 0000000000350ef0

Call Trace:
<NMI>
</NMI>
<IRQ>

lock_acquire kernel/locking/lockdep.c:5754 [inline]
lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719
__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+0xd5/0xc60 net/sched/sch_taprio.c:934
__run_hrtimer kernel/time/hrtimer.c:1688 [inline]
__hrtimer_run_queues+0x203/0xc20 kernel/time/hrtimer.c:1752

hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1065 [inline]
__sysvec_apic_timer_interrupt+0x105/0x400 arch/x86/kernel/apic/apic.c:1082
sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1076
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645

RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:206
Code: 66 0f 1f 44 00 00 f3 0f 1e fa 48 8b be b0 01 00 00 e8 b0 ff ff ff 31 c0 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa <65> 48 8b 14 25 c0 bc 03 00 65 8b 05 74 32 7c 7e a9 00 01 ff 00 48
RSP: 0018:ffffc90004cf7970 EFLAGS: 00000246
RAX: ffff88806a0f4c40 RBX: ffff888028217c00 RCX: ffffffff8a700d11
RDX: ffff888025675940 RSI: ffffffff8a700b05 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000005
R10: 000000000000000f R11: 0000000000000001 R12: 00007f588be4efff
R13: 0000000000000005 R14: 000055dc48e02000 R15: dffffc0000000000
ma_slots lib/maple_tree.c:785 [inline]
mas_get_slot lib/maple_tree.c:6673 [inline]
mas_validate_gaps lib/maple_tree.c:6942 [inline]
mt_validate+0x2771/0x3e90 lib/maple_tree.c:7217
validate_mm+0x9a/0x4b0 mm/mmap.c:288
mmap_region+0x15c8/0x2830 mm/mmap.c:2974
do_mmap+0x893/0xef0 mm/mmap.c:1379
vm_mmap_pgoff+0x1a8/0x3c0 mm/util.c:556
ksys_mmap_pgoff+0x422/0x5b0 mm/mmap.c:1425
__do_sys_mmap arch/x86/kernel/sys_x86_64.c:93 [inline]
__se_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline]
__x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:86

do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

RIP: 0033:0x7f588c16cb74
Code: 63 08 44 89 e8 5b 41 5c 41 5d c3 41 89 ca 41 f7 c1 ff 0f 00 00 74 0c c7 05 f5 46 01 00 16 00 00 00 eb 17 b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 0c f7 d8 89 05 dc 46 01 00 48 83 c8 ff c3 0f
RSP: 002b:00007ffeec15f508 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007ffeec15f580 RCX: 00007f588c16cb74
RDX: 0000000000000001 RSI: 0000000000025000 RDI: 00007f588be7d000
RBP: 00007ffeec15f8a0 R08: 0000000000000003 R09: 000000000002e000
R10: 0000000000000812 R11: 0000000000000246 R12: 00007f588c150570
R13: 00007ffeec15f928 R14: 000000000002d9c6 R15: 0000000000000000
</TASK>


Tested on:

commit: 18d46e76 Merge tag 'for-6.7-rc3-tag' of git://git.kern..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12c9bf2ce80000

kernel config: https://syzkaller.appspot.com/x/.config?x=bb39fe85d254f638
dashboard link: https://syzkaller.appspot.com/bug?extid=de8e83db70e8beedd556
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=1340351ce80000