Subject: [syzbot] [perf?] WARNING: suspicious RCU usage in __schedule (2)

From: syzbot <[email-masked]>
Date: Thu, 18 Apr 2024 12:49:21 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    443574b03387 riscv, bpf: Fix kfunc parameters incompatibil..
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=1348ceb3180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
dashboard link: https://syzkaller.appspot.com/bug?extid=ae891a39094db8049d6c
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/3f355021a085/disk-443574b0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/44cf4de7472a/vmlinux-443574b0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a99a36c7ad65/bzImage-443574b0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

=============================
WARNING: suspicious RCU usage
6.8.0-syzkaller-05236-g443574b03387 #0 Not tainted
-----------------------------
kernel/sched/core.c:5982 Illegal context switch in RCU-bh read-side critical section!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz-executor.4/5285:
 #0: ffffffff94511910 (&pmus_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:116 [inline]
 #0: ffffffff94511910 (&pmus_srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:215 [inline]
 #0: ffffffff94511910 (&pmus_srcu){.+.+}-{0:0}, at: perf_init_event kernel/events/core.c:11698 [inline]
 #0: ffffffff94511910 (&pmus_srcu){.+.+}-{0:0}, at: perf_event_alloc+0xacf/0x2130 kernel/events/core.c:12018

stack backtrace:
CPU: 1 PID: 5285 Comm: syz-executor.4 Not tainted 6.8.0-syzkaller-05236-g443574b03387 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712
 schedule_debug kernel/sched/core.c:5982 [inline]
 __schedule+0x23b/0x4a20 kernel/sched/core.c:6629
 preempt_schedule_notrace+0x100/0x140 kernel/sched/core.c:7008
 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:13
 trace_contention_end+0x108/0x120 include/trace/events/lock.h:122
 __pv_queued_spin_lock_slowpath+0x939/0xc60 kernel/locking/qspinlock.c:560
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
 queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 lockdep_lock+0x1b0/0x2b0 kernel/locking/lockdep.c:144
 graph_lock+0x5/0x60 kernel/locking/lockdep.c:170
 mark_lock+0x15c/0x350 kernel/locking/lockdep.c:4659
 mark_usage kernel/locking/lockdep.c:4587 [inline]
 __lock_acquire+0x112d/0x1fd0 kernel/locking/lockdep.c:5091
 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
 percpu_down_write+0x57/0x320 kernel/locking/percpu-rwsem.c:229
 bp_constraints_lock+0xdd/0x1c0 kernel/events/hw_breakpoint.c:133
 reserve_bp_slot kernel/events/hw_breakpoint.c:600 [inline]
 register_perf_hw_breakpoint+0x90/0x250 kernel/events/hw_breakpoint.c:718
 hw_breakpoint_event_init+0x8d/0x110 kernel/events/hw_breakpoint.c:958
 perf_try_init_event+0x139/0x3f0 kernel/events/core.c:11668
 perf_init_event kernel/events/core.c:11738 [inline]
 perf_event_alloc+0xeed/0x2130 kernel/events/core.c:12018
 __do_sys_perf_event_open kernel/events/core.c:12525 [inline]
 __se_sys_perf_event_open+0x7f9/0x38d0 kernel/events/core.c:12416
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f1ad6e7de69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1ad7c780c8 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f1ad6fabf80 RCX: 00007f1ad6e7de69
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000020000180
RBP: 00007f1ad6eca47a R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f1ad6fabf80 R15: 00007fff0dbffce8
 </TASK>

=============================
WARNING: suspicious RCU usage
6.8.0-syzkaller-05236-g443574b03387 #0 Not tainted
-----------------------------
kernel/sched/core.c:5982 Illegal context switch in RCU-sched read-side critical section!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz-executor.4/5285:
 #0: ffffffff94511910 (&pmus_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:116 [inline]
 #0: ffffffff94511910 (&pmus_srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:215 [inline]
 #0: ffffffff94511910 (&pmus_srcu){.+.+}-{0:0}, at: perf_init_event kernel/events/core.c:11698 [inline]
 #0: ffffffff94511910 (&pmus_srcu){.+.+}-{0:0}, at: perf_event_alloc+0xacf/0x2130 kernel/events/core.c:12018

stack backtrace:
CPU: 1 PID: 5285 Comm: syz-executor.4 Not tainted 6.8.0-syzkaller-05236-g443574b03387 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712
 schedule_debug kernel/sched/core.c:5982 [inline]
 __schedule+0x28a/0x4a20 kernel/sched/core.c:6629
 preempt_schedule_notrace+0x100/0x140 kernel/sched/core.c:7008
 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:13
 trace_contention_end+0x108/0x120 include/trace/events/lock.h:122
 __pv_queued_spin_lock_slowpath+0x939/0xc60 kernel/locking/qspinlock.c:560
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
 queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 lockdep_lock+0x1b0/0x2b0 kernel/locking/lockdep.c:144
 graph_lock+0x5/0x60 kernel/locking/lockdep.c:170
 mark_lock+0x15c/0x350 kernel/locking/lockdep.c:4659
 mark_usage kernel/locking/lockdep.c:4587 [inline]
 __lock_acquire+0x112d/0x1fd0 kernel/locking/lockdep.c:5091
 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
 percpu_down_write+0x57/0x320 kernel/locking/percpu-rwsem.c:229
 bp_constraints_lock+0xdd/0x1c0 kernel/events/hw_breakpoint.c:133
 reserve_bp_slot kernel/events/hw_breakpoint.c:600 [inline]
 register_perf_hw_breakpoint+0x90/0x250 kernel/events/hw_breakpoint.c:718
 hw_breakpoint_event_init+0x8d/0x110 kernel/events/hw_breakpoint.c:958
 perf_try_init_event+0x139/0x3f0 kernel/events/core.c:11668
 perf_init_event kernel/events/core.c:11738 [inline]
 perf_event_alloc+0xeed/0x2130 kernel/events/core.c:12018
 __do_sys_perf_event_open kernel/events/core.c:12525 [inline]
 __se_sys_perf_event_open+0x7f9/0x38d0 kernel/events/core.c:12416
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f1ad6e7de69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1ad7c780c8 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f1ad6fabf80 RCX: 00007f1ad6e7de69
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000020000180
RBP: 00007f1ad6eca47a R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f1ad6fabf80 R15: 00007fff0dbffce8
 </TASK>

---
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