./strace-static-x86_64 -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f ./syz-executor23043446 <...> Warning: Permanently added '10.128.0.67' (ECDSA) to the list of known hosts. execve("./syz-executor23043446", ["./syz-executor23043446"], 0x7ffe44294fd0 /* 10 vars */) = 0 brk(NULL) = 0x55555621d000 brk(0x55555621dc40) = 0x55555621dc40 arch_prctl(ARCH_SET_FS, 0x55555621d300) = 0 uname({sysname="Linux", nodename="syzkaller", ...}) = 0 readlink("/proc/self/exe", "/root/syz-executor23043446", 4096) = 26 brk(0x55555623ec40) = 0x55555623ec40 brk(0x55555623f000) = 0x55555623f000 mprotect(0x7facd1bea000, 16384, PROT_READ) = 0 mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000 mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000 mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000 socket(AF_INET6, SOCK_DGRAM, IPPROTO_IP) = 3 setsockopt(3, SOL_SOCKET, SO_REUSEPORT, [6], 4) = 0 bind(3, {sa_family=AF_INET6, sin6_port=htons(20000), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "::", &sin6_addr), sin6_scope_id=0}, 28) = 0 exit_group(0) = ? syzkaller login: [ 45.843247][ T3609] [ 45.845693][ T3609] ============================= [ 45.850599][ T3609] WARNING: suspicious RCU usage [ 45.855432][ T3609] 6.0.0-rc1-next-20220818-syzkaller #0 Not tainted [ 45.861951][ T3609] ----------------------------- [ 45.866783][ T3609] include/net/sock.h:592 suspicious rcu_dereference_check() usage! [ 45.874711][ T3609] [ 45.874711][ T3609] other info that might help us debug this: [ 45.874711][ T3609] [ 45.884969][ T3609] [ 45.884969][ T3609] rcu_scheduler_active = 2, debug_locks = 1 [ 45.893097][ T3609] 4 locks held by syz-executor230/3609: [ 45.898690][ T3609] #0: ffff888075042c10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release+0x86/0x280 [ 45.909297][ T3609] #1: ffffc900014c32b8 (&table->hash[i].lock){+...}-{2:2}, at: udp_lib_unhash+0x1d5/0x730 [ 45.919389][ T3609] #2: ffffffff8d7beb78 (reuseport_lock){+...}-{2:2}, at: reuseport_detach_sock+0x22/0x4a0 [ 45.929460][ T3609] #3: ffff88814b002bb8 (clock-AF_INET6){++..}-{2:2}, at: bpf_sk_reuseport_detach+0x26/0x190 [ 45.939718][ T3609] [ 45.939718][ T3609] stack backtrace: [ 45.945595][ T3609] CPU: 1 PID: 3609 Comm: syz-executor230 Not tainted 6.0.0-rc1-next-20220818-syzkaller #0 [ 45.955494][ T3609] syz-executor230[3609] cmdline: a [ 45.961287][ T3609] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 [ 45.971344][ T3609] Call Trace: [ 45.974617][ T3609] [ 45.977542][ T3609] dump_stack_lvl+0xcd/0x134 [ 45.982140][ T3609] bpf_sk_reuseport_detach+0x156/0x190 [ 45.987609][ T3609] reuseport_detach_sock+0x8c/0x4a0 [ 45.992820][ T3609] udp_lib_unhash+0x210/0x730 [ 45.997499][ T3609] ? udpv6_pre_connect+0x180/0x180 [ 46.002601][ T3609] sk_common_release+0xba/0x390 [ 46.007463][ T3609] inet_release+0x12e/0x270 [ 46.011969][ T3609] inet6_release+0x4c/0x70 [ 46.016392][ T3609] __sock_release+0xcd/0x280 [ 46.020976][ T3609] sock_close+0x18/0x20 [ 46.025136][ T3609] __fput+0x27c/0xa90 [ 46.029113][ T3609] ? __sock_release+0x280/0x280 [ 46.033961][ T3609] task_work_run+0xdd/0x1a0 [ 46.038457][ T3609] do_exit+0xc39/0x2b60 [ 46.042612][ T3609] ? lock_downgrade+0x6e0/0x6e0 [ 46.047454][ T3609] ? do_raw_spin_lock+0x120/0x2a0 [ 46.052472][ T3609] ? mm_update_next_owner+0x7a0/0x7a0 [ 46.057834][ T3609] ? rwlock_bug.part.0+0x90/0x90 [ 46.062785][ T3609] ? _raw_spin_unlock_irq+0x1f/0x40 [ 46.068236][ T3609] ? _raw_spin_unlock_irq+0x1f/0x40 [ 46.073427][ T3609] do_group_exit+0xd0/0x2a0 [ 46.077924][ T3609] __x64_sys_exit_group+0x3a/0x50 [ 46.082940][ T3609] do_syscall_64+0x35/0xb0 [ 46.087349][ T3609] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 46.093234][ T3609] RIP: 0033:0x7facd1b7c679 [ 46.097653][ T3609] Code: Unable to access opcode bytes at RIP 0x7facd1b7c64f. [ 46.105015][ T3609] RSP: 002b:00007ffd7870e908 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 46.113425][ T3609] RAX: ffffffffffffffda RBX: 00007facd1bf0270 RCX: 00007facd1b7c679 [ 46.121387][ T3609] RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 [ 46.129346][ T3609] RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000000000000 +++ exited with 0 +++ [ 46.137303][ T3609] R10: 0000000000000004 R11: 0000000000000246 R12: 00007facd1bf0