bpfilter: read fail -512 ============================= WARNING: suspicious RCU usage 4.17.0+ #84 Not tainted ----------------------------- kernel/pid.c:323 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by syz-executor7/29997: device lo entered promiscuous mode #0: 000000001e4dec85 (bpfilter_lock){+.+.}, at: __bpfilter_process_sockopt+0x1bd/0x384 net/bpfilter/bpfilter_kern.c:67 stack backtrace: CPU: 1 PID: 29997 Comm: syz-executor7 Not tainted 4.17.0+ #84 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 IPVS: ftp: loaded support on port[0] = 21 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x14a/0x153 kernel/locking/lockdep.c:4562 pid_task+0x1b9/0x1e0 kernel/pid.c:322 shutdown_umh.constprop.0+0x33/0x7c net/bpfilter/bpfilter_kern.c:29 __stop_umh net/bpfilter/bpfilter_kern.c:41 [inline] __bpfilter_process_sockopt.cold.1+0x9b/0xa0 net/bpfilter/bpfilter_kern.c:81 bpfilter_mbox_request+0x4d/0xb0 net/ipv4/bpfilter/sockopt.c:25 bpfilter_ip_get_sockopt+0x6b/0x90 net/ipv4/bpfilter/sockopt.c:42 ip_getsockopt+0x238/0x2a0 net/ipv4/ip_sockglue.c:1563 tcp_getsockopt+0x93/0xe0 net/ipv4/tcp.c:3534 sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:3012 smc_getsockopt+0xc7/0x120 net/smc/af_smc.c:1473 __sys_getsockopt+0x1a5/0x370 net/socket.c:1984 __do_sys_getsockopt net/socket.c:1995 [inline] __se_sys_getsockopt net/socket.c:1992 [inline] __x64_sys_getsockopt+0xbe/0x150 net/socket.c:1992 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455b29 Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f0391bdbc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007f0391bdc6d4 RCX: 0000000000455b29 RDX: 0000000000000043 RSI: 0000000000000000 RDI: 0000000000000016 RBP: 000000000072bea0 R08: 0000000020000040 R09: 0000000000000000 R10: 0000000020000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004c3808 R14: 00000000004c8f78 R15: 0000000000000000 netlink: 220 bytes leftover after parsing attributes in process `syz-executor2'.