Hello, I reproduced this bug in the syzbot dashboard and upstream linux. If you fix this issue, please add the following tag to the commit: Reported-by: xingwei lee <xrivendell7@xxxxxxxxx> I use the same config with syzbot dashboard. kernel version: c1ca10ceffbb289ed02feaf005bc9ee6095b4507 kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=e3dd779fba027968 with KMSAN enabled compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 [ 254.423842][ T8047] ===================================================== [ 254.430576][ T8047] BUG: KMSAN: uninit-value in __nla_validate_parse+0x3d62/0x4f90 [ 254.434357][ T8047] __nla_validate_parse+0x3d62/0x4f90 [ 254.437054][ T8047] __nla_parse+0x6a/0x80 [ 254.439556][ T8047] nfnetlink_rcv_msg+0x74c/0xed0 [ 254.444928][ T8047] netlink_rcv_skb+0x58f/0x6d0 [ 254.447359][ T8047] nfnetlink_rcv+0x3e8/0x4d10 [ 254.449893][ T8047] netlink_unicast+0x107c/0x13e0 [ 254.452371][ T8047] netlink_sendmsg+0x132c/0x1540 [ 254.454791][ T8047] ____sys_sendmsg+0xa5b/0xe70 [ 254.456975][ T8047] ___sys_sendmsg+0x2a7/0x3f0 [ 254.459423][ T8047] __x64_sys_sendmsg+0x342/0x510 [ 254.461514][ T8047] do_syscall_64+0xcf/0x1e0 [ 254.463345][ T8047] entry_SYSCALL_64_after_hwframe+0x63/0x6b [ 254.465643][ T8047] [ 254.466539][ T8047] Uninit was created at: [ 254.468194][ T8047] kmem_cache_alloc_node+0x5cb/0xbc0 [ 254.470272][ T8047] kmalloc_reserve+0x14d/0x500 [ 254.471882][ T8047] __alloc_skb+0x385/0x820 [ 254.473385][ T8047] netlink_sendmsg+0xbd6/0x1540 [ 254.475011][ T8047] ____sys_sendmsg+0xa5b/0xe70 [ 254.476534][ T8047] ___sys_sendmsg+0x2a7/0x3f0 [ 254.478039][ T8047] __x64_sys_sendmsg+0x342/0x510 [ 254.479628][ T8047] do_syscall_64+0xcf/0x1e0 [ 254.480995][ T8047] entry_SYSCALL_64_after_hwframe+0x63/0x6b [ 254.482719][ T8047] =* repro.c =* #define _GNU_SOURCE #include <dirent.h> #include <endian.h> #include <errno.h> #include <fcntl.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; } #define BITMASK(bf_off, bf_len) (((1ull << (bf_len)) - 1) << (bf_off)) #define STORE_BY_BITMASK(type, htobe, addr, val, bf_off, bf_len) \ *(type*)(addr) = \ htobe((htobe(*(type*)(addr)) & ~BITMASK((bf_off), (bf_len))) | \ (((type)(val) << (bf_off)) & BITMASK((bf_off), (bf_len)))) 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"); } 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[1] = {0xffffffffffffffff}; void execute_one(void) { intptr_t res = 0; res = syscall(__NR_socket, /*domain=*/0x10ul, /*type=*/3ul, /*proto=*/0xc); if (res != -1) r[0] = res; *(uint64_t*)0x20000080 = 0; *(uint32_t*)0x20000088 = 0; *(uint64_t*)0x20000090 = 0x20000040; *(uint64_t*)0x20000040 = 0x20000100; *(uint32_t*)0x20000100 = 0x18; *(uint8_t*)0x20000104 = 0; *(uint8_t*)0x20000105 = 0xb; *(uint16_t*)0x20000106 = 0x401; *(uint32_t*)0x20000108 = 0; *(uint32_t*)0x2000010c = 0; *(uint8_t*)0x20000110 = 0; *(uint8_t*)0x20000111 = 0; *(uint16_t*)0x20000112 = htobe16(0); *(uint16_t*)0x20000114 = 4; STORE_BY_BITMASK(uint16_t, , 0x20000116, 2, 0, 14); STORE_BY_BITMASK(uint16_t, , 0x20000117, 0, 6, 1); STORE_BY_BITMASK(uint16_t, , 0x20000117, 1, 7, 1); *(uint64_t*)0x20000048 = 0x18; *(uint64_t*)0x20000098 = 1; *(uint64_t*)0x200000a0 = 0; *(uint64_t*)0x200000a8 = 0; *(uint32_t*)0x200000b0 = 0; syscall(__NR_sendmsg, /*fd=*/r[0], /*msg=*/0x20000080ul, /*f=*/0ul); } 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$nl_netfilter(0x10, 0x3, 0xc) sendmsg$IPCTNL_MSG_CT_NEW(r0, &(0x7f0000000080)={0x0, 0x0, &(0x7f0000000040)={&(0x7f0000000100)={0x18, 0x0, 0xb, 0x401, 0x0, 0x0, {}, [@CTA_TUPLE_REPLY={0x4}]}, 0x18}}, 0x0) and see also in https://gist.github.com/xrivendell7/fe97316e8a66f8d81109a158a3225bc0 I hope it helps. Best regards! xingwei Lee
