[syzbot] [bpf?] possible deadlock in __stack_map_get

From: syzbot
Date: Thu Apr 18 2024 - 16:00:48 EST

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Hello,

syzbot found the following issue on:

HEAD commit: f99c5f563c17 Merge tag 'nf-24-03-21' of git://git.kernel.o..
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15d7c52b180000
kernel config: https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
dashboard link: https://syzkaller.appspot.com/bug?extid=dddd99ae26c656485d89
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=10869857180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f1f7cb180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/65d3f3eb786e/disk-f99c5f56.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/799cf7f28ff8/vmlinux-f99c5f56.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ab26c60c3845/bzImage-f99c5f56.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dddd99ae26c656485d89@xxxxxxxxxxxxxxxxxxxxxxxxx

============================================
WARNING: possible recursive locking detected
6.8.0-syzkaller-05271-gf99c5f563c17 #0 Not tainted
--------------------------------------------
syz-executor224/5098 is trying to acquire lock:
ffff888021ef61d8 (&qs->lock){-.-.}-{2:2}, at: __stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140

but task is already holding lock:
ffff888021ef51d8 (&qs->lock){-.-.}-{2:2}, at: __stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&qs->lock);
lock(&qs->lock);

*** DEADLOCK ***

May be due to missing lock nesting notation

4 locks held by syz-executor224/5098:
#0: ffffffff8e200c68 (pcpu_alloc_mutex){+.+.}-{3:3}, at: pcpu_alloc+0x27b/0x1670 mm/percpu.c:1769
#1: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#1: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
#1: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline]
#1: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x114/0x420 kernel/trace/bpf_trace.c:2420
#2: ffff888021ef51d8 (&qs->lock){-.-.}-{2:2}, at: __stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140
#3: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#3: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
#3: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline]
#3: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x114/0x420 kernel/trace/bpf_trace.c:2420

stack backtrace:
CPU: 0 PID: 5098 Comm: syz-executor224 Not tainted 6.8.0-syzkaller-05271-gf99c5f563c17 #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
check_deadlock kernel/locking/lockdep.c:3062 [inline]
validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
__stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140
bpf_prog_7a16b54e5ee857f9+0x42/0x46
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x204/0x420 kernel/trace/bpf_trace.c:2420
__traceiter_contention_end+0x7b/0xb0 include/trace/events/lock.h:122
trace_contention_end+0xf6/0x120 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]
do_raw_spin_lock+0x272/0x370 kernel/locking/spinlock_debug.c:116
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0xe1/0x120 kernel/locking/spinlock.c:162
__stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140
bpf_prog_7a16b54e5ee857f9+0x42/0x46
bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
__bpf_prog_run include/linux/filter.h:657 [inline]
bpf_prog_run include/linux/filter.h:664 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
bpf_trace_run2+0x204/0x420 kernel/trace/bpf_trace.c:2420
__traceiter_contention_end+0x7b/0xb0 include/trace/events/lock.h:122
trace_contention_end+0xd7/0x100 include/trace/events/lock.h:122
__mutex_lock_common kernel/locking/mutex.c:617 [inline]
__mutex_lock+0x2e5/0xd70 kernel/locking/mutex.c:752
pcpu_alloc+0x27b/0x1670 mm/percpu.c:1769
bpf_prog_alloc_no_stats+0x10b/0x4a0 kernel/bpf/core.c:112
bpf_prog_alloc+0x3b/0x1b0 kernel/bpf/core.c:144
bpf_prog_load+0x7f7/0x20f0 kernel/bpf/syscall.c:2805
__sys_bpf+0x4ee/0x810 kernel/bpf/syscall.c:5631
__do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5736
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7fb8f4667f69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 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:00007ffc6855faf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb8f4667f69
RDX: 0000000000000090 RSI: 00000000200000c0 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00000000000000a0 R09: 00000000000000a0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>

---
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Next message: Samuel Holland: "Re: [PATCH v7 08/24] drivers/perf: riscv: Implement SBI PMU snapshot function"
Previous message: Sean Christopherson: "Re: [PATCH 1/4] KVM: delete .change_pte MMU notifier callback"
Next in thread: Hillf Danton: "Re: [syzbot] [bpf?] possible deadlock in __stack_map_get"
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