| // INFO: task hung in grab_super |
| // https://syzkaller.appspot.com/bug?id=83071d6b1a930234bea81149f0ba905d7ef66c05 |
| // status:open |
| // autogenerated by syzkaller (https://github.com/google/syzkaller) |
| |
| #define _GNU_SOURCE |
| |
| #include <dirent.h> |
| #include <endian.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <pthread.h> |
| #include <setjmp.h> |
| #include <signal.h> |
| #include <stdarg.h> |
| #include <stdbool.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/ioctl.h> |
| #include <sys/mount.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> |
| |
| #include <linux/futex.h> |
| #include <linux/loop.h> |
| |
| unsigned long long procid; |
| |
| static __thread int skip_segv; |
| static __thread jmp_buf segv_env; |
| |
| static void segv_handler(int sig, siginfo_t* info, void* ctx) |
| { |
| uintptr_t addr = (uintptr_t)info->si_addr; |
| const uintptr_t prog_start = 1 << 20; |
| const uintptr_t prog_end = 100 << 20; |
| if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && |
| (addr < prog_start || addr > prog_end)) { |
| _longjmp(segv_env, 1); |
| } |
| exit(sig); |
| } |
| |
| static void install_segv_handler(void) |
| { |
| struct sigaction sa; |
| memset(&sa, 0, sizeof(sa)); |
| sa.sa_handler = SIG_IGN; |
| syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8); |
| syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8); |
| memset(&sa, 0, sizeof(sa)); |
| sa.sa_sigaction = segv_handler; |
| sa.sa_flags = SA_NODEFER | SA_SIGINFO; |
| sigaction(SIGSEGV, &sa, NULL); |
| sigaction(SIGBUS, &sa, NULL); |
| } |
| |
| #define NONFAILING(...) \ |
| { \ |
| __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ |
| if (_setjmp(segv_env) == 0) { \ |
| __VA_ARGS__; \ |
| } \ |
| __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ |
| } |
| |
| 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 use_temporary_dir(void) |
| { |
| char tmpdir_template[] = "./syzkaller.XXXXXX"; |
| char* tmpdir = mkdtemp(tmpdir_template); |
| if (!tmpdir) |
| exit(1); |
| if (chmod(tmpdir, 0777)) |
| exit(1); |
| if (chdir(tmpdir)) |
| exit(1); |
| } |
| |
| 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; |
| for (i = 0; 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); |
| } |
| |
| 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_RELAXED)) |
| 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; |
| } |
| |
| struct fs_image_segment { |
| void* data; |
| uintptr_t size; |
| uintptr_t offset; |
| }; |
| |
| #define IMAGE_MAX_SEGMENTS 4096 |
| #define IMAGE_MAX_SIZE (129 << 20) |
| |
| #define SYZ_memfd_create 319 |
| |
| static long syz_mount_image(volatile long fsarg, volatile long dir, |
| volatile unsigned long size, |
| volatile unsigned long nsegs, |
| volatile long segments, volatile long flags, |
| volatile long optsarg) |
| { |
| char loopname[64], fs[32], opts[256]; |
| int loopfd, err = 0, res = -1; |
| unsigned long i; |
| struct fs_image_segment* segs = (struct fs_image_segment*)segments; |
| if (nsegs > IMAGE_MAX_SEGMENTS) |
| nsegs = IMAGE_MAX_SEGMENTS; |
| for (i = 0; i < nsegs; i++) { |
| if (segs[i].size > IMAGE_MAX_SIZE) |
| segs[i].size = IMAGE_MAX_SIZE; |
| segs[i].offset %= IMAGE_MAX_SIZE; |
| if (segs[i].offset > IMAGE_MAX_SIZE - segs[i].size) |
| segs[i].offset = IMAGE_MAX_SIZE - segs[i].size; |
| if (size < segs[i].offset + segs[i].offset) |
| size = segs[i].offset + segs[i].offset; |
| } |
| if (size > IMAGE_MAX_SIZE) |
| size = IMAGE_MAX_SIZE; |
| int memfd = syscall(SYZ_memfd_create, "syz_mount_image", 0); |
| if (memfd == -1) { |
| err = errno; |
| goto error; |
| } |
| if (ftruncate(memfd, size)) { |
| err = errno; |
| goto error_close_memfd; |
| } |
| for (i = 0; i < nsegs; i++) { |
| if (pwrite(memfd, segs[i].data, segs[i].size, segs[i].offset) < 0) { |
| } |
| } |
| snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid); |
| loopfd = open(loopname, O_RDWR); |
| if (loopfd == -1) { |
| err = errno; |
| goto error_close_memfd; |
| } |
| if (ioctl(loopfd, LOOP_SET_FD, memfd)) { |
| if (errno != EBUSY) { |
| err = errno; |
| goto error_close_loop; |
| } |
| ioctl(loopfd, LOOP_CLR_FD, 0); |
| usleep(1000); |
| if (ioctl(loopfd, LOOP_SET_FD, memfd)) { |
| err = errno; |
| goto error_close_loop; |
| } |
| } |
| mkdir((char*)dir, 0777); |
| memset(fs, 0, sizeof(fs)); |
| NONFAILING(strncpy(fs, (char*)fsarg, sizeof(fs) - 1)); |
| memset(opts, 0, sizeof(opts)); |
| NONFAILING(strncpy(opts, (char*)optsarg, sizeof(opts) - 32)); |
| if (strcmp(fs, "iso9660") == 0) { |
| flags |= MS_RDONLY; |
| } else if (strncmp(fs, "ext", 3) == 0) { |
| if (strstr(opts, "errors=panic") || strstr(opts, "errors=remount-ro") == 0) |
| strcat(opts, ",errors=continue"); |
| } else if (strcmp(fs, "xfs") == 0) { |
| strcat(opts, ",nouuid"); |
| } |
| if (mount(loopname, (char*)dir, fs, flags, opts)) { |
| err = errno; |
| goto error_clear_loop; |
| } |
| res = 0; |
| error_clear_loop: |
| ioctl(loopfd, LOOP_CLR_FD, 0); |
| error_close_loop: |
| close(loopfd); |
| error_close_memfd: |
| close(memfd); |
| error: |
| errno = err; |
| return res; |
| } |
| |
| #define FS_IOC_SETFLAGS _IOW('f', 2, long) |
| static void remove_dir(const char* dir) |
| { |
| DIR* dp; |
| struct dirent* ep; |
| int iter = 0; |
| retry: |
| while (umount2(dir, MNT_DETACH) == 0) { |
| } |
| dp = opendir(dir); |
| if (dp == NULL) { |
| if (errno == EMFILE) { |
| exit(1); |
| } |
| exit(1); |
| } |
| while ((ep = readdir(dp))) { |
| if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0) |
| continue; |
| char filename[FILENAME_MAX]; |
| snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name); |
| while (umount2(filename, MNT_DETACH) == 0) { |
| } |
| struct stat st; |
| if (lstat(filename, &st)) |
| exit(1); |
| if (S_ISDIR(st.st_mode)) { |
| remove_dir(filename); |
| continue; |
| } |
| int i; |
| for (i = 0;; i++) { |
| if (unlink(filename) == 0) |
| break; |
| if (errno == EPERM) { |
| int fd = open(filename, O_RDONLY); |
| if (fd != -1) { |
| long flags = 0; |
| if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) |
| close(fd); |
| continue; |
| } |
| } |
| if (errno == EROFS) { |
| break; |
| } |
| if (errno != EBUSY || i > 100) |
| exit(1); |
| if (umount2(filename, MNT_DETACH)) |
| exit(1); |
| } |
| } |
| closedir(dp); |
| int i; |
| for (i = 0;; i++) { |
| if (rmdir(dir) == 0) |
| break; |
| if (i < 100) { |
| if (errno == EPERM) { |
| int fd = open(dir, O_RDONLY); |
| if (fd != -1) { |
| long flags = 0; |
| if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) |
| close(fd); |
| continue; |
| } |
| } |
| if (errno == EROFS) { |
| break; |
| } |
| if (errno == EBUSY) { |
| if (umount2(dir, MNT_DETACH)) |
| exit(1); |
| continue; |
| } |
| if (errno == ENOTEMPTY) { |
| if (iter < 100) { |
| iter++; |
| goto retry; |
| } |
| } |
| } |
| exit(1); |
| } |
| } |
| |
| static void kill_and_wait(int pid, int* status) |
| { |
| kill(-pid, SIGKILL); |
| kill(pid, SIGKILL); |
| int i; |
| for (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) { |
| } |
| } |
| |
| #define SYZ_HAVE_RESET_LOOP 1 |
| static void reset_loop() |
| { |
| char buf[64]; |
| snprintf(buf, sizeof(buf), "/dev/loop%llu", procid); |
| int loopfd = open(buf, O_RDWR); |
| if (loopfd != -1) { |
| ioctl(loopfd, LOOP_CLR_FD, 0); |
| close(loopfd); |
| } |
| } |
| |
| #define SYZ_HAVE_SETUP_TEST 1 |
| 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; |
| int collide = 0; |
| again: |
| for (call = 0; call < 3; 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); |
| if (collide && (call % 2) == 0) |
| break; |
| event_timedwait(&th->done, 45); |
| break; |
| } |
| } |
| for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++) |
| sleep_ms(1); |
| if (!collide) { |
| collide = 1; |
| goto again; |
| } |
| } |
| |
| static void execute_one(void); |
| |
| #define WAIT_FLAGS __WALL |
| |
| static void loop(void) |
| { |
| int iter; |
| for (iter = 0;; iter++) { |
| char cwdbuf[32]; |
| sprintf(cwdbuf, "./%d", iter); |
| if (mkdir(cwdbuf, 0777)) |
| exit(1); |
| reset_loop(); |
| int pid = fork(); |
| if (pid < 0) |
| exit(1); |
| if (pid == 0) { |
| if (chdir(cwdbuf)) |
| exit(1); |
| 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 < 5 * 1000) |
| continue; |
| kill_and_wait(pid, &status); |
| break; |
| } |
| remove_dir(cwdbuf); |
| } |
| } |
| |
| void execute_call(int call) |
| { |
| switch (call) { |
| case 0: |
| NONFAILING(memcpy((void*)0x20000140, "./file0\000", 8)); |
| syscall(__NR_mknod, 0x20000140, 0x10020006004, 0x701 + procid * 2); |
| break; |
| case 1: |
| NONFAILING(memcpy((void*)0x20000080, "./file0\000", 8)); |
| NONFAILING(memcpy((void*)0x20000200, "./file0\000", 8)); |
| NONFAILING(memcpy((void*)0x20000240, "udf\000", 4)); |
| syscall(__NR_mount, 0x20000080, 0x20000200, 0x20000240, 0, 0); |
| break; |
| case 2: |
| syz_mount_image(0, 0, 0x400000, 0, 0, 1, 0); |
| break; |
| } |
| } |
| int main(void) |
| { |
| syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); |
| install_segv_handler(); |
| for (procid = 0; procid < 6; procid++) { |
| if (fork() == 0) { |
| use_temporary_dir(); |
| loop(); |
| } |
| } |
| sleep(1000000); |
| return 0; |
| } |