Subject: [syzbot] [bpf?] [net?] BUG: sleeping function called from invalid context in sock_map_delete_elem

From: syzbot <[email-masked]>
Date: Wed, 27 Aug 2025 16:56:27 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    8d245acc1e88 Merge tag 'char-misc-6.17-rc3' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11513062580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e1e1566c7726877e
dashboard link: https://syzkaller.appspot.com/bug?extid=1f1fbecb9413cdbfbef8
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=109d7062580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=126bea34580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/096739d8f0ec/disk-8d245acc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/83a21aa9b978/vmlinux-8d245acc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7e7f165a3b29/bzImage-8d245acc.xz

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

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6107, name: syz.0.17
preempt_count: 1, expected: 0
RCU nest depth: 1, expected: 1
3 locks held by syz.0.17/6107:
 #0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: bpf_test_timer_enter+0x1a/0x140 net/bpf/test_run.c:40
 #1: ffffffff8d84a760 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0xa1/0x400 kernel/softirq.c:163
 #2: ffff888032e15a98 (&stab->lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock_rt.h:88 [inline]
 #2: ffff888032e15a98 (&stab->lock){+...}-{3:3}, at: __sock_map_delete net/core/sock_map.c:421 [inline]
 #2: ffff888032e15a98 (&stab->lock){+...}-{3:3}, at: sock_map_delete_elem+0xb7/0x170 net/core/sock_map.c:452
Preemption disabled at:
[<ffffffff891fce58>] bpf_test_timer_enter+0xf8/0x140 net/bpf/test_run.c:42
CPU: 0 UID: 0 PID: 6107 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 __might_resched+0x44b/0x5d0 kernel/sched/core.c:8957
 __rt_spin_lock kernel/locking/spinlock_rt.c:48 [inline]
 rt_spin_lock+0xc7/0x2c0 kernel/locking/spinlock_rt.c:57
 spin_lock_bh include/linux/spinlock_rt.h:88 [inline]
 __sock_map_delete net/core/sock_map.c:421 [inline]
 sock_map_delete_elem+0xb7/0x170 net/core/sock_map.c:452
 bpf_prog_2c29ac5cdc6b1842+0x43/0x4b
 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline]
 __bpf_prog_run include/linux/filter.h:718 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 bpf_prog_run_pin_on_cpu include/linux/filter.h:742 [inline]
 bpf_flow_dissect+0x132/0x400 net/core/flow_dissector.c:1024
 bpf_prog_test_run_flow_dissector+0x37c/0x5c0 net/bpf/test_run.c:1416
 bpf_prog_test_run+0x2ca/0x340 kernel/bpf/syscall.c:4590
 __sys_bpf+0x581/0x870 kernel/bpf/syscall.c:6047
 __do_sys_bpf kernel/bpf/syscall.c:6139 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6137 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6137
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f637004ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffc4e2e8a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f6370275fa0 RCX: 00007f637004ebe9
RDX: 0000000000000050 RSI: 0000200000000180 RDI: 000000000000000a
RBP: 00007f63700d1e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6370275fa0 R14: 00007f6370275fa0 R15: 0000000000000003
 </TASK>

---
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