[resending as plain text] Hello,
The following program triggers WARNING in kcm_write_msgs: WARNING: CPU: 3 PID: 2936 at net/kcm/kcmsock.c:627 kcm_write_msgs+0x12e3/0x1b90 net/kcm/kcmsock.c:627 CPU: 3 PID: 2936 Comm: a.out Not tainted 4.10.0-rc6+ #209 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:15 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:51 panic+0x1fb/0x412 kernel/panic.c:179 __warn+0x1c4/0x1e0 kernel/panic.c:539 warn_slowpath_null+0x2c/0x40 kernel/panic.c:582 kcm_write_msgs+0x12e3/0x1b90 net/kcm/kcmsock.c:627 kcm_sendmsg+0x163a/0x2200 net/kcm/kcmsock.c:1029 sock_sendmsg_nosec net/socket.c:635 [inline] sock_sendmsg+0xca/0x110 net/socket.c:645 sock_write_iter+0x326/0x600 net/socket.c:848 new_sync_write fs/read_write.c:499 [inline] __vfs_write+0x483/0x740 fs/read_write.c:512 vfs_write+0x187/0x530 fs/read_write.c:560 SYSC_write fs/read_write.c:607 [inline] SyS_write+0xfb/0x230 fs/read_write.c:599 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x434c09 RSP: 002b:00007fff40f2d7b8 EFLAGS: 00000217 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000401960 RCX: 0000000000434c09 RDX: 0000000000000000 RSI: 00000000208aaf27 RDI: 0000000000000005 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fff00000000 R10: 0000000000000000 R11: 0000000000000217 R12: 00000000004002b0 R13: 0000000000401960 R14: 00000000004019f0 R15: 0000000000000000 // autogenerated by syzkaller (http://github.com/google/syzkaller) #define _GNU_SOURCE #include <sys/ioctl.h> #include <sys/stat.h> #include <sys/syscall.h> #include <sys/time.h> #include <sys/types.h> #include <sys/socket.h> #include <linux/in.h> #include <stddef.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #ifndef __NR_bpf #define __NR_bpf 321 #endif #ifndef AF_KCM #define AF_KCM 0x29 #endif int main() { syscall(__NR_mmap, 0x20000000ul, 0xfff000ul, 0x3ul, 0x32ul, -1, 0); int sock = socket(AF_INET6, SOCK_STREAM, IPPROTO_IP); (*(uint32_t*)0x20b4ffd0 = (uint32_t)0x1); (*(uint32_t*)0x20b4ffd4 = (uint32_t)0x2); (*(uint64_t*)0x20b4ffd8 = (uint64_t)0x20b4f000); (*(uint64_t*)0x20b4ffe0 = (uint64_t)0x2015a000); (*(uint32_t*)0x20b4ffe8 = (uint32_t)0x9); (*(uint32_t*)0x20b4ffec = (uint32_t)0x80); (*(uint64_t*)0x20b4fff0 = (uint64_t)0x20b4f000); (*(uint32_t*)0x20b4fff8 = (uint32_t)0x0); (*(uint8_t*)0x20b4f000 = (uint8_t)0xffffffffffffffb7); (*(uint8_t*)0x20b4f001 = (uint8_t)0x0); (*(uint16_t*)0x20b4f002 = (uint16_t)0x0); (*(uint32_t*)0x20b4f004 = (uint32_t)0x0); (*(uint8_t*)0x20b4f008 = (uint8_t)0x9595); (*(uint8_t*)0x20b4f009 = (uint8_t)0x0); (*(uint16_t*)0x20b4f00a = (uint16_t)0x0); (*(uint32_t*)0x20b4f00c = (uint32_t)0x0); (memcpy((void*)0x2015a000, "\x00\x8b", 2)); int bpf = syscall(__NR_bpf, 0x5ul, 0x20b4ffd0ul, 0x30ul, 0, 0, 0, 0, 0, 0); int sock2 = syscall(__NR_socket, AF_KCM, 0x5ul, 0x0ul); (*(uint32_t*)0x20b5c000 = sock); (*(uint32_t*)0x20b5c004 = bpf); syscall(__NR_ioctl, sock2, 0x89e0ul, 0x20b5c000ul); syscall(__NR_write, sock2, 0x208aaf27ul, 0x0ul); return 0; } On commit a572a1b999489efb591287632279c6c9eca3e4ed
