Hello I found a bug in net/dccp in the lastest upstream linux 6.7.rc5 and lastest net tree titled general protection fault in dccp_write_xmit If you fix this issue, please add the following tag to the commit: Reported-by: xingwei Lee <xrivendell7@xxxxxxxxx> kernel: net.git c3e041425af9068e3ec9d90c536de2a2ba97ba2b Kernel config: https://github.com/google/syzkaller/commits/17e6d52686f8a56935991f1b066798279f76504a in the lastest net tree commit, the crash like: CPU: 1 PID: 8151 Comm: 096 Not tainted 6.7.0-rc4-00151-gc3e041425af9 #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:ccid_hc_tx_send_packet home/dubbo/net/net/dccp/ccid.h:166 [inline] RIP: 0010:dccp_write_xmit+0x66/0x1d0 home/dubbo/net/net/dccp/output.c:356 Code: 00 48 85 c0 49 89 c4 0f 84 03 01 00 00 e8 12 1d 0d f8 41 80 3e 00 0f 85 45 01 00 00 48 8b 9d f0 08 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 1f 01 00 00 48 8b 1b 48 8d bb b0 00 00 00 48 RSP: 0018:ffffc90010fcf878 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88814ea6a540 RSI: ffffffff897ab2ce RDI: ffff8881555b8b40 RBP: ffff8881555b8b40 R08: 0000000000000001 R09: fffffbfff23317ec R10: ffffffff9198bf67 R11: 0000000000000001 R12: ffff88814c691700 R13: dffffc0000000000 R14: ffffed102aab7286 R15: ffff8881555b9430 FS: 00007f74af0706c0(0000) GS:ffff88823bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200001c0 CR3: 0000000154391000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> dccp_sendmsg+0x968/0xcc0 home/dubbo/net/net/dccp/proto.c:801 inet_sendmsg+0x9d/0xe0 home/dubbo/net/net/ipv4/af_inet.c:847 sock_sendmsg_nosec home/dubbo/net/net/socket.c:730 [inline] __sock_sendmsg+0xd5/0x180 home/dubbo/net/net/socket.c:745 ____sys_sendmsg+0x2b0/0x880 home/dubbo/net/net/socket.c:2584 ___sys_sendmsg+0x135/0x1d0 home/dubbo/net/net/socket.c:2638 __sys_sendmmsg+0x1a1/0x450 home/dubbo/net/net/socket.c:2724 __do_sys_sendmmsg home/dubbo/net/net/socket.c:2753 [inline] __se_sys_sendmmsg home/dubbo/net/net/socket.c:2750 [inline] __x64_sys_sendmmsg+0x9c/0x100 home/dubbo/net/net/socket.c:2750 do_syscall_x64 home/dubbo/net/arch/x86/entry/common.c:52 [inline] do_syscall_64+0x3f/0x110 home/dubbo/net/arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x4368e9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f74af0701e8 EFLAGS: 00000213 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f74af0706c0 RCX: 00000000004368e9 RDX: 0000000000000001 RSI: 0000000020000200 RDI: 0000000000000006 RBP: 00007f74af070220 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000048000 R11: 0000000000000213 R12: ffffffffffffffb0 R13: 0000000000000000 R14: 00007ffecb287a30 R15: 00007ffecb287b18 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ccid_hc_tx_send_packet home/dubbo/net/net/dccp/ccid.h:166 [inline] RIP: 0010:dccp_write_xmit+0x66/0x1d0 home/dubbo/net/net/dccp/output.c:356 Code: 00 48 85 c0 49 89 c4 0f 84 03 01 00 00 e8 12 1d 0d f8 41 80 3e 00 0f 85 45 01 00 00 48 8b 9d f0 08 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 1f 01 00 00 48 8b 1b 48 8d bb b0 00 00 00 48 RSP: 0018:ffffc90010fcf878 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88814ea6a540 RSI: ffffffff897ab2ce RDI: ffff8881555b8b40 RBP: ffff8881555b8b40 R08: 0000000000000001 R09: fffffbfff23317ec R10: ffffffff9198bf67 R11: 0000000000000001 R12: ffff88814c691700 R13: dffffc0000000000 R14: ffffed102aab7286 R15: ffff8881555b9430 FS: 00007f74af0706c0(0000) GS:ffff88823bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200001c0 CR3: 0000000154391000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Kernel panic - not syncing: Fatal exception Kernel Offset: disabled Rebooting in 86400 seconds.. ---------------- Code disassembly (best guess): 0: 00 48 85 add %cl,-0x7b(%rax) 3: c0 49 89 c4 rorb $0xc4,-0x77(%rcx) 7: 0f 84 03 01 00 00 je 0x110 d: e8 12 1d 0d f8 call 0xf80d1d24 12: 41 80 3e 00 cmpb $0x0,(%r14) 16: 0f 85 45 01 00 00 jne 0x161 1c: 48 8b 9d f0 08 00 00 mov 0x8f0(%rbp),%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction 2f: 0f 85 1f 01 00 00 jne 0x154 35: 48 8b 1b mov (%rbx),%rbx 38: 48 8d bb b0 00 00 00 lea 0xb0(%rbx),%rdi 3f: 48 rex.W =* repro.c =* #define _GNU_SOURCE #include <dirent.h> #include <endian.h> #include <errno.h> #include <fcntl.h> #include <linux/futex.h> #include <pthread.h> #include <signal.h> #include <stdarg.h> #include <stdbool.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/prctl.h> #include <sys/stat.h> #include <sys/syscall.h> #include <sys/types.h> #include <sys/wait.h> #include <time.h> #include <unistd.h> static void sleep_ms(uint64_t ms) { usleep(ms * 1000); } static uint64_t current_time_ms(void) { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) exit(1); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } static void thread_start(void* (*fn)(void*), void* arg) { pthread_t th; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setstacksize(&attr, 128 << 10); int i = 0; for (; i < 100; i++) { if (pthread_create(&th, &attr, fn, arg) == 0) { pthread_attr_destroy(&attr); return; } if (errno == EAGAIN) { usleep(50); continue; } break; } exit(1); } typedef struct { int state; } event_t; static void event_init(event_t* ev) { ev->state = 0; } static void event_reset(event_t* ev) { ev->state = 0; } static void event_set(event_t* ev) { if (ev->state) exit(1); __atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE); syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1000000); } static void event_wait(event_t* ev) { while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0); } static int event_isset(event_t* ev) { return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE); } static int event_timedwait(event_t* ev, uint64_t timeout) { uint64_t start = current_time_ms(); uint64_t now = start; for (;;) { uint64_t remain = timeout - (now - start); struct timespec ts; ts.tv_sec = remain / 1000; ts.tv_nsec = (remain % 1000) * 1000 * 1000; syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts); if (__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE)) return 1; now = current_time_ms(); if (now - start > timeout) return 0; } } static bool write_file(const char* file, const char* what, ...) { char buf[1024]; va_list args; va_start(args, what); vsnprintf(buf, sizeof(buf), what, args); va_end(args); buf[sizeof(buf) - 1] = 0; int len = strlen(buf); int fd = open(file, O_WRONLY | O_CLOEXEC); if (fd == -1) return false; if (write(fd, buf, len) != len) { int err = errno; close(fd); errno = err; return false; } close(fd); return true; } static void kill_and_wait(int pid, int* status) { kill(-pid, SIGKILL); kill(pid, SIGKILL); for (int i = 0; i < 100; i++) { if (waitpid(-1, status, WNOHANG | __WALL) == pid) return; usleep(1000); } DIR* dir = opendir("/sys/fs/fuse/connections"); if (dir) { for (;;) { struct dirent* ent = readdir(dir); if (!ent) break; if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue; char abort[300]; snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort", ent->d_name); int fd = open(abort, O_WRONLY); if (fd == -1) { continue; } if (write(fd, abort, 1) < 0) { } close(fd); } closedir(dir); } else { } while (waitpid(-1, status, __WALL) != pid) { } } static void setup_test() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); write_file("/proc/self/oom_score_adj", "1000"); } struct thread_t { int created, call; event_t ready, done; }; static struct thread_t threads[16]; static void execute_call(int call); static int running; static void* thr(void* arg) { struct thread_t* th = (struct thread_t*)arg; for (;;) { event_wait(&th->ready); event_reset(&th->ready); execute_call(th->call); __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED); event_set(&th->done); } return 0; } static void execute_one(void) { int i, call, thread; for (call = 0; call < 10; call++) { for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0])); thread++) { struct thread_t* th = &threads[thread]; if (!th->created) { th->created = 1; event_init(&th->ready); event_init(&th->done); event_set(&th->done); thread_start(thr, th); } if (!event_isset(&th->done)) continue; event_reset(&th->done); th->call = call; __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED); event_set(&th->ready); event_timedwait(&th->done, 50); break; } } for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++) sleep_ms(1); } static void execute_one(void); #define WAIT_FLAGS __WALL static void loop(void) { int iter = 0; for (;; iter++) { int pid = fork(); if (pid < 0) exit(1); if (pid == 0) { setup_test(); execute_one(); exit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break; sleep_ms(1); if (current_time_ms() - start < 5000) continue; kill_and_wait(pid, &status); break; } } } uint64_t r[5] = {0xffffffffffffffff, 0xffffffffffffffff, 0x0, 0xffffffffffffffff, 0xffffffffffffffff}; void execute_call(int call) { intptr_t res = 0; switch (call) { case 0: res = syscall(__NR_socket, /*domain=*/0x10ul, /*type=*/0x803ul, /*proto=*/0); if (res != -1) r[0] = res; break; case 1: res = syscall(__NR_socket, /*domain=*/0xaul, /*type=*/1ul, /*proto=*/0); if (res != -1) r[1] = res; break; case 2: memcpy((void*)0x200001c0, "wg1\000\000\000\000\000\000\000\000\000\000\000\000\000", 16); res = syscall(__NR_ioctl, /*fd=*/r[1], /*cmd=*/0x8933, /*arg=*/0x200001c0ul); if (res != -1) r[2] = *(uint32_t*)0x200001d0; break; case 3: *(uint64_t*)0x20000340 = 0; *(uint32_t*)0x20000348 = 0; *(uint64_t*)0x20000350 = 0x20002840; *(uint64_t*)0x20002840 = 0x20000080; *(uint32_t*)0x20000080 = 0x2c; *(uint16_t*)0x20000084 = 0x14; *(uint16_t*)0x20000086 = 1; *(uint32_t*)0x20000088 = 0; *(uint32_t*)0x2000008c = 0; *(uint8_t*)0x20000090 = 0xa; *(uint8_t*)0x20000091 = 0; *(uint8_t*)0x20000092 = 0; *(uint8_t*)0x20000093 = 0; *(uint32_t*)0x20000094 = r[2]; *(uint16_t*)0x20000098 = 0x14; *(uint16_t*)0x2000009a = 2; *(uint8_t*)0x2000009c = 0xfe; *(uint8_t*)0x2000009d = 0x80; memset((void*)0x2000009e, 0, 13); *(uint8_t*)0x200000ab = 0xbb; *(uint64_t*)0x20002848 = 0x2c; *(uint64_t*)0x20000358 = 1; *(uint64_t*)0x20000360 = 0; *(uint64_t*)0x20000368 = 0; *(uint32_t*)0x20000370 = 0; syscall(__NR_sendmsg, /*fd=*/r[0], /*msg=*/0x20000340ul, /*f=*/0ul); break; case 4: res = syscall(__NR_socket, /*domain=*/0xaul, /*type=*/6ul, /*proto=*/0); if (res != -1) r[3] = res; break; case 5: *(uint16_t*)0x20000000 = 0xa; *(uint16_t*)0x20000002 = htobe16(0); *(uint32_t*)0x20000004 = htobe32(0); *(uint64_t*)0x20000008 = htobe64(0); *(uint64_t*)0x20000010 = htobe64(0xa0211fffe000000); *(uint32_t*)0x20000018 = 0; syscall(__NR_connect, /*fd=*/r[3], /*addr=*/0x20000000ul, /*addrlen=*/0x1cul); break; case 6: res = syscall(__NR_dup, /*oldfd=*/r[3]); if (res != -1) r[4] = res; break; case 7: *(uint64_t*)0x20000200 = 0; *(uint32_t*)0x20000208 = 0; *(uint64_t*)0x20000210 = 0; *(uint64_t*)0x20000218 = 0; *(uint64_t*)0x20000220 = 0; *(uint64_t*)0x20000228 = 0; *(uint32_t*)0x20000230 = 0; *(uint32_t*)0x20000238 = 0; syscall(__NR_sendmmsg, /*fd=*/r[4], /*mmsg=*/0x20000200ul, /*vlen=*/1ul, /*f=*/0x48000ul); break; case 8: syscall(__NR_shutdown, /*fd=*/r[3], /*how=*/0ul); break; case 9: *(uint16_t*)0x20000000 = 0xa; *(uint16_t*)0x20000002 = htobe16(0); *(uint32_t*)0x20000004 = htobe32(0); *(uint64_t*)0x20000008 = htobe64(0); *(uint64_t*)0x20000010 = htobe64(0xa0211fffe000000); *(uint32_t*)0x20000018 = 0; syscall(__NR_connect, /*fd=*/r[3], /*addr=*/0x20000000ul, /*addrlen=*/0x1cul); break; } } int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=*/7ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); loop(); return 0; } =* repro.txt =* r0 = socket(0x10, 0x803, 0x0) r1 = socket$inet6(0xa, 0x1, 0x0) ioctl$ifreq_SIOCGIFINDEX_wireguard(r1, 0x8933, &(0x7f00000001c0)={'wg1\x00', <r2=>0x0}) sendmsg$nl_route(r0, &(0x7f0000000340)={0x0, 0x0, &(0x7f0000002840)={&(0x7f0000000080)=@ipv6_newaddr={0x2c, 0x14, 0x1, 0x0, 0x0, {0xa, 0x0, 0x0, 0x0, r2}, [@IFA_LOCAL={0x14, 0x2, @remote}]}, 0x2c}}, 0x0) r3 = socket$inet6(0xa, 0x6, 0x0) connect$inet6(r3, &(0x7f0000000000)={0xa, 0x0, 0x0, @loopback={0x0, 0xa0211fffe000000}}, 0x1c) r4 = dup(r3) sendmmsg$inet6(r4, &(0x7f0000000200)=[{{0x0, 0x0, 0x0}}], 0x1, 0x48000) shutdown(r3, 0x0) connect$inet6(r3, &(0x7f0000000000)={0xa, 0x0, 0x0, @loopback={0x0, 0xa0211fffe000000}}, 0x1c) Please see also https://gist.github.com/xrivendell7/93aebd97f6d43b735e45a66e8650c2ad
