On Mon, Dec 25, 2017 at 05:45:00PM -0800, syzbot wrote: > syzkaller has found reproducer for the following crash on > fba961ab29e5ffb055592442808bb0f7962e05da > git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > C reproducer is attached > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable > > ============================= > WARNING: suspicious RCU usage > 4.15.0-rc4+ #164 Not tainted > ----------------------------- > ./include/net/inet_sock.h:136 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > rcu_scheduler_active = 2, debug_locks = 1 > 1 lock held by syzkaller667189/5780: > #0: (sk_lock-AF_INET6){+.+.}, at: [<000000008d7d4e62>] lock_sock > include/net/sock.h:1462 [inline] > #0: (sk_lock-AF_INET6){+.+.}, at: [<000000008d7d4e62>] > do_ipv6_setsockopt.isra.9+0x23d/0x38f0 net/ipv6/ipv6_sockglue.c:167 > > stack backtrace: > CPU: 0 PID: 5780 Comm: syzkaller667189 Not tainted 4.15.0-rc4+ #164 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:17 [inline] > dump_stack+0x194/0x257 lib/dump_stack.c:53 > lockdep_rcu_suspicious+0x123/0x170 kernel/locking/lockdep.c:4585 > ireq_opt_deref include/net/inet_sock.h:135 [inline] > inet_csk_route_req+0x824/0xca0 net/ipv4/inet_connection_sock.c:544 > dccp_v4_send_response+0xa7/0x640 net/dccp/ipv4.c:485 > dccp_v4_conn_request+0x9ee/0x11b0 net/dccp/ipv4.c:633 > dccp_v6_conn_request+0xd30/0x1350 net/dccp/ipv6.c:317 > dccp_rcv_state_process+0x574/0x1620 net/dccp/input.c:612 > dccp_v4_do_rcv+0xeb/0x160 net/dccp/ipv4.c:682 > dccp_v6_do_rcv+0x81a/0x9b0 net/dccp/ipv6.c:578 > sk_backlog_rcv include/net/sock.h:907 [inline] > __release_sock+0x124/0x360 net/core/sock.c:2274 > release_sock+0xa4/0x2a0 net/core/sock.c:2789 > do_ipv6_setsockopt.isra.9+0x50f/0x38f0 net/ipv6/ipv6_sockglue.c:898 > ipv6_setsockopt+0xd7/0x150 net/ipv6/ipv6_sockglue.c:922 > dccp_setsockopt+0x85/0xd0 net/dccp/proto.c:573 > sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2978 > SYSC_setsockopt net/socket.c:1821 [inline] > SyS_setsockopt+0x189/0x360 net/socket.c:1800 > entry_SYSCALL_64_fastpath+0x1f/0x96 > RIP: 0033:0x445ec9 > RSP: 002b:00007fa001b58db8 EFLAGS: 00000297 ORIG_RAX: 0000000000000036 > RAX: ffffffffffffffda RBX: 00000000006dbc24 RCX: 0000000000445ec9 > RDX: 0000000000000020 RSI: 0000000000000029 RDI: 0000000000000004 > RBP: 00000000006dbc20 R08: 0000000000000020 R09: 0000000000000000 > R10: 000000002030a000 R11: 0000000000000297 R12: 0000000000000000 > R13: 00007fff809eec1f R14: 00007fa001b599c0 R15: 0000000000000001 > > ============================= > WARNING: suspicious RCU usage > 4.15.0-rc4+ #164 Not tainted > ----------------------------- > ./include/net/inet_sock.h:136 suspicious rcu_dereference_check() usage! > > other info that might help us debug this: > > > rcu_scheduler_active = 2, debug_locks = 1 > 1 lock held by syzkaller667189/5780: > #0: (sk_lock-AF_INET6){+.+.}, at: [<000000008d7d4e62>] lock_sock > include/net/sock.h:1462 [inline] > #0: (sk_lock-AF_INET6){+.+.}, at: [<000000008d7d4e62>] > do_ipv6_setsockopt.isra.9+0x23d/0x38f0 net/ipv6/ipv6_sockglue.c:167 > > stack backtrace: > CPU: 0 PID: 5780 Comm: syzkaller667189 Not tainted 4.15.0-rc4+ #164 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:17 [inline] > dump_stack+0x194/0x257 lib/dump_stack.c:53 > lockdep_rcu_suspicious+0x123/0x170 kernel/locking/lockdep.c:4585 > ireq_opt_deref include/net/inet_sock.h:135 [inline] > dccp_v4_send_response+0x4b0/0x640 net/dccp/ipv4.c:496 > dccp_v4_conn_request+0x9ee/0x11b0 net/dccp/ipv4.c:633 > dccp_v6_conn_request+0xd30/0x1350 net/dccp/ipv6.c:317 > dccp_rcv_state_process+0x574/0x1620 net/dccp/input.c:612 > dccp_v4_do_rcv+0xeb/0x160 net/dccp/ipv4.c:682 > dccp_v6_do_rcv+0x81a/0x9b0 net/dccp/ipv6.c:578 > sk_backlog_rcv include/net/sock.h:907 [inline] > __release_sock+0x124/0x360 net/core/sock.c:2274 > release_sock+0xa4/0x2a0 net/core/sock.c:2789 > do_ipv6_setsockopt.isra.9+0x50f/0x38f0 net/ipv6/ipv6_sockglue.c:898 > ipv6_setsockopt+0xd7/0x150 net/ipv6/ipv6_sockglue.c:922 > dccp_setsockopt+0x85/0xd0 net/dccp/proto.c:573 > sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2978 > SYSC_setsockopt net/socket.c:1821 [inline] > SyS_setsockopt+0x189/0x360 net/socket.c:1800 > entry_SYSCALL_64_fastpath+0x1f/0x96 > RIP: 0033:0x445ec9 > RSP: 002b:00007fa001b58db8 EFLAGS: 00000297 ORIG_RAX: 0000000000000036 > RAX: ffffffffffffffda RBX: 00000000006dbc24 RCX: 0000000000445ec9 > RDX: 0000000000000020 RSI: 0000000000000029 RDI: 0000000000000004 > RBP: 00000000006dbc20 R08: 0000000000000020 R09: 0000000000000000 > R10: 000000002030a000 R11: 0000000000000297 R12: 0000000000000000 > R13: 00007fff809eec1f R14: 00007fa001b599c0 R15: 0000000000000001 syzbot stopped hitting this for some reason, but the bug is still there. Here's a simplified reproducer that works on Linus' tree as of today: #include <linux/in.h> #include <stdlib.h> #include <sys/socket.h> #include <unistd.h> int main() { int is_parent = (fork() != 0); for (;;) { int fd = socket(AF_INET, SOCK_DCCP, 0); struct sockaddr_in addr = { .sin_family = AF_INET, .sin_port = htobe16(0x4e23), }; if (is_parent) { connect(fd, (void *)&addr, sizeof(addr)); } else { bind(fd, (void *)&addr, sizeof(addr)); listen(fd, 100); setsockopt(fd, 0, 0xFFFF, NULL, 0); } close(fd); } } -- To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
