[v5.15] INFO: rcu detected stall in sys_bpf

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 12952a23a5da Linux 5.15.137
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=144c090d680000
kernel config: https://syzkaller.appspot.com/x/.config?x=fec74236cf840914
dashboard link: https://syzkaller.appspot.com/bug?extid=fbd30621f95f7c034ccd
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0102e80bd83/disk-12952a23.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ad4bb1832eb8/vmlinux-12952a23.xz
kernel image: https://storage.googleapis.com/syzbot-assets/530bbc85fac0/bzImage-12952a23.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fbd306...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13468/1:b..l
(detected by 1, t=10503 jiffies, g=64605, q=2621)
task:syz-executor.4 state:R running task stack:24280 pid:13468 ppid: 3552 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5026 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6372
preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6776
irqentry_exit+0x53/0x80 kernel/entry/common.c:426
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:__sanitizer_cov_trace_pc+0x41/0x60 kernel/kcov.c:202
Code: ff 00 74 11 f7 c2 00 01 00 00 74 35 83 b9 34 16 00 00 00 74 2c 8b 91 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89
RSP: 0018:ffffc90004e376d8 EFLAGS: 00000246
RAX: ffffffff817bde79 RBX: ffffffff8c7cc9c8 RCX: ffff88801bc1bb80
RDX: ffffc900063ab000 RSI: 000000000003ffff RDI: 00000000ffffffff
RBP: ffffc90004e377a0 R08: ffffffff817bde65 R09: ffffed1003783771
R10: 0000000000000000 R11: 0000000000000001 R12: 1ffff920009c6ee0
R13: 0000000000000001 R14: 0000000000000000 R15: dffffc0000000000
from_kuid_munged+0x1e9/0x7b0 kernel/user_namespace.c:452
____bpf_get_socket_uid net/core/filter.c:4721 [inline]
bpf_get_socket_uid+0x162/0x230 net/core/filter.c:4713
bpf_prog_b1dcf3ca3fd1caf6+0x6f/0x7b4
bpf_dispatcher_nop_func include/linux/bpf.h:776 [inline]
__bpf_prog_run include/linux/filter.h:625 [inline]
bpf_prog_run include/linux/filter.h:632 [inline]
bpf_test_run+0x3f4/0x8a0 net/bpf/test_run.c:119
bpf_prog_test_run_skb+0xb41/0x1420 net/bpf/test_run.c:663
bpf_prog_test_run+0x32f/0x3a0 kernel/bpf/syscall.c:3331
__sys_bpf+0x3ac/0x670 kernel/bpf/syscall.c:4632
__do_sys_bpf kernel/bpf/syscall.c:4718 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4716 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4716
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+0x61/0xcb
RIP: 0033:0x7fbd34562ae9
RSP: 002b:00007fbd32ae40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fbd34681f80 RCX: 00007fbd34562ae9
RDX: 0000000000000040 RSI: 00000000200002c0 RDI: 000000000000000a
RBP: 00007fbd345ae47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fbd34681f80 R15: 00007ffc7ccd0c58
</TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10325 jiffies! g64605 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=44279
rcu: rcu_preempt kthread starved for 10328 jiffies! g64605 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:27000 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5026 [inline]
__schedule+0x12c4/0x45b0 kernel/sched/core.c:6372
schedule+0x11b/0x1f0 kernel/sched/core.c:6455
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884
rcu_gp_fqs_loop+0x2af/0xf70 kernel/rcu/tree.c:1959
rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2132
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 1376 Comm: aoe_tx0 Not tainted 5.15.137-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
RIP: 0010:trace_lock_release include/trace/events/lock.h:58 [inline]
RIP: 0010:lock_release+0xb2/0x9a0 kernel/locking/lockdep.c:5633
Code: 83 fb 08 0f 83 d3 05 00 00 89 d8 c1 e8 06 48 8d 3c c5 28 8f e3 8d be 08 00 00 00 e8 08 36 67 00 89 d8 48 0f a3 05 d6 eb 80 0c <73> 0d e8 b7 42 08 00 84 c0 0f 84 d8 05 00 00 48 c7 c0 c4 c2 e3 8d
RSP: 0018:ffffc90005b07840 EFLAGS: 00000057
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8162a348
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8de38f28
RBP: ffffc90005b07970 R08: dffffc0000000000 R09: fffffbfff1bc71e6
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000b60f14
R13: ffffffff8476e0f7 R14: ffffc90005b079a0 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1a4d1440f0 CR3: 00000000231b5000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline]
_raw_spin_unlock_irqrestore+0x75/0x130 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
uart_write_room+0x137/0x2e0 drivers/tty/serial/serial_core.c:603
handle_tx+0x164/0x620 drivers/net/caif/caif_serial.c:226
__netdev_start_xmit include/linux/netdevice.h:5019 [inline]
netdev_start_xmit include/linux/netdevice.h:5033 [inline]
xmit_one net/core/dev.c:3614 [inline]
dev_hard_start_xmit+0x298/0x7a0 net/core/dev.c:3630
__dev_queue_xmit+0x1cee/0x3230 net/core/dev.c:4245
tx+0x64/0x100 drivers/block/aoe/aoenet.c:63
kthread+0x234/0x440 drivers/block/aoe/aoecmd.c:1230
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>


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[syzbot]

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