Syzkaller hit 'memory leak in setup_mq_sysctls' bug. BUG: memory leak unreferenced object 0xffff88800eb6c400 (size 512): comm "syz-executor939", pid 278, jiffies 4294881721 (age 25.346s) hex dump (first 32 bytes): 60 d3 79 84 ff ff ff ff 8c a7 83 17 80 88 ff ff `.y............. 04 00 00 00 a4 01 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000002d336ba9>] kmemdup+0x23/0x50 [<000000003491df85>] setup_mq_sysctls+0x59/0x230 [<000000000cabac74>] copy_ipcs+0x381/0x5d0 [<000000006d2953c7>] create_new_namespaces+0x210/0xb30 [<00000000456ac2c1>] unshare_nsproxy_namespaces+0xc1/0x1f0 [<00000000f93be355>] ksys_unshare+0x445/0x8d0 [<000000007209e9b4>] __x64_sys_unshare+0x2d/0x40 [<000000009d1bd17f>] do_syscall_64+0x3b/0x90 [<00000000614eca25>] entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced object 0xffff88800ede2000 (size 256): comm "syz-executor939", pid 278, jiffies 4294881721 (age 25.346s) hex dump (first 32 bytes): 00 c4 b6 0e 80 88 ff ff 00 00 00 00 01 00 00 00 ................ 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000008e1e2258>] __register_sysctl_table+0x112/0x1090 [<00000000c948c674>] setup_mq_sysctls+0x13c/0x230 [<000000000cabac74>] copy_ipcs+0x381/0x5d0 [<000000006d2953c7>] create_new_namespaces+0x210/0xb30 [<00000000456ac2c1>] unshare_nsproxy_namespaces+0xc1/0x1f0 [<00000000f93be355>] ksys_unshare+0x445/0x8d0 [<000000007209e9b4>] __x64_sys_unshare+0x2d/0x40 [<000000009d1bd17f>] do_syscall_64+0x3b/0x90 [<00000000614eca25>] entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced object 0xffff88800ede2200 (size 256): comm "syz-executor939", pid 278, jiffies 4294881721 (age 25.346s) hex dump (first 32 bytes): 78 22 de 0e 80 88 ff ff 00 00 00 00 01 00 00 00 x".............. 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000bdc5abc9>] __register_sysctl_table+0x9e2/0x1090 [<00000000c948c674>] setup_mq_sysctls+0x13c/0x230 [<000000000cabac74>] copy_ipcs+0x381/0x5d0 [<000000006d2953c7>] create_new_namespaces+0x210/0xb30 [<00000000456ac2c1>] unshare_nsproxy_namespaces+0xc1/0x1f0 [<00000000f93be355>] ksys_unshare+0x445/0x8d0 [<000000007209e9b4>] __x64_sys_unshare+0x2d/0x40 [<000000009d1bd17f>] do_syscall_64+0x3b/0x90 [<00000000614eca25>] entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced object 0xffff88800ede2400 (size 256): comm "syz-executor939", pid 278, jiffies 4294881721 (age 25.346s) hex dump (first 32 bytes): 78 24 de 0e 80 88 ff ff 00 00 00 00 01 00 00 00 x$.............. 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000bdc5abc9>] __register_sysctl_table+0x9e2/0x1090 [<00000000c948c674>] setup_mq_sysctls+0x13c/0x230 [<000000000cabac74>] copy_ipcs+0x381/0x5d0 [<000000006d2953c7>] create_new_namespaces+0x210/0xb30 [<00000000456ac2c1>] unshare_nsproxy_namespaces+0xc1/0x1f0 [<00000000f93be355>] ksys_unshare+0x445/0x8d0 [<000000007209e9b4>] __x64_sys_unshare+0x2d/0x40 [<000000009d1bd17f>] do_syscall_64+0x3b/0x90 [<00000000614eca25>] entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced object 0xffff88800eb6f400 (size 512): comm "syz-executor939", pid 279, jiffies 4294892033 (age 15.034s) hex dump (first 32 bytes): 60 d3 79 84 ff ff ff ff 8c e7 83 17 80 88 ff ff `.y............. 04 00 00 00 a4 01 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000002d336ba9>] kmemdup+0x23/0x50 [<000000003491df85>] setup_mq_sysctls+0x59/0x230 [<000000000cabac74>] copy_ipcs+0x381/0x5d0 [<000000006d2953c7>] create_new_namespaces+0x210/0xb30 [<00000000456ac2c1>] unshare_nsproxy_namespaces+0xc1/0x1f0 [<00000000f93be355>] ksys_unshare+0x445/0x8d0 [<000000007209e9b4>] __x64_sys_unshare+0x2d/0x40 [<000000009d1bd17f>] do_syscall_64+0x3b/0x90 [<00000000614eca25>] entry_SYSCALL_64_after_hwframe+0x44/0xae Syzkaller reproducer: # {Threaded:false Collide:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none Leak:true NetInjection:false NetDevices:false NetReset:false Cgroups:true BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false UseTmpDir:true HandleSegv:false Repro:false Trace:false LegacyOptions:{Fault:false FaultCall:0 FaultNth:0}} unshare(0x8000000) (fail_nth: 53) C reproducer: // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static unsigned long long procid; 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 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; } #define MAX_FDS 30 static void mount_cgroups(const char* dir, const char** controllers, int count) { if (mkdir(dir, 0777)) { } char enabled[128] = {0}; int i = 0; for (; i < count; i++) { if (mount("none", dir, "cgroup", 0, controllers[i])) { continue; } umount(dir); strcat(enabled, ","); strcat(enabled, controllers[i]); } if (enabled[0] == 0) return; if (mount("none", dir, "cgroup", 0, enabled + 1)) { } if (chmod(dir, 0777)) { } } static void setup_cgroups() { const char* unified_controllers[] = {"+cpu", "+memory", "+io", "+pids"}; const char* net_controllers[] = {"net", "net_prio", "devices", "blkio", "freezer"}; const char* cpu_controllers[] = {"cpuset", "cpuacct", "hugetlb", "rlimit"}; if (mkdir("/syzcgroup", 0777)) { } if (mkdir("/syzcgroup/unified", 0777)) { } if (mount("none", "/syzcgroup/unified", "cgroup2", 0, NULL)) { } if (chmod("/syzcgroup/unified", 0777)) { } int unified_control = open("/syzcgroup/unified/cgroup.subtree_control", O_WRONLY); if (unified_control != -1) { unsigned i; for (i = 0; i < sizeof(unified_controllers) / sizeof(unified_controllers[0]); i++) if (write(unified_control, unified_controllers[i], strlen(unified_controllers[i])) < 0) { } close(unified_control); } mount_cgroups("/syzcgroup/net", net_controllers, sizeof(net_controllers) / sizeof(net_controllers[0])); mount_cgroups("/syzcgroup/cpu", cpu_controllers, sizeof(cpu_controllers) / sizeof(cpu_controllers[0])); write_file("/syzcgroup/cpu/cgroup.clone_children", "1"); write_file("/syzcgroup/cpu/cpuset.memory_pressure_enabled", "1"); } static void setup_cgroups_loop() { int pid = getpid(); char file[128]; char cgroupdir[64]; snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/unified/syz%llu", procid); if (mkdir(cgroupdir, 0777)) { } snprintf(file, sizeof(file), "%s/pids.max", cgroupdir); write_file(file, "32"); snprintf(file, sizeof(file), "%s/memory.low", cgroupdir); write_file(file, "%d", 298 << 20); snprintf(file, sizeof(file), "%s/memory.high", cgroupdir); write_file(file, "%d", 299 << 20); snprintf(file, sizeof(file), "%s/memory.max", cgroupdir); write_file(file, "%d", 300 << 20); snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir); write_file(file, "%d", pid); snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/cpu/syz%llu", procid); if (mkdir(cgroupdir, 0777)) { } snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir); write_file(file, "%d", pid); snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/net/syz%llu", procid); if (mkdir(cgroupdir, 0777)) { } snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir); write_file(file, "%d", pid); } static void setup_cgroups_test() { char cgroupdir[64]; snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/unified/syz%llu", procid); if (symlink(cgroupdir, "./cgroup")) { } snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/cpu/syz%llu", procid); if (symlink(cgroupdir, "./cgroup.cpu")) { } snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/net/syz%llu", procid); if (symlink(cgroupdir, "./cgroup.net")) { } } static void setup_common() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) { } } static void setup_binderfs() { if (mkdir("/dev/binderfs", 0777)) { } if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) { } } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setsid(); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = (200 << 20); setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 32 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 136 << 20; setrlimit(RLIMIT_FSIZE, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_STACK, &rlim); rlim.rlim_cur = rlim.rlim_max = 0; setrlimit(RLIMIT_CORE, &rlim); rlim.rlim_cur = rlim.rlim_max = 256; setrlimit(RLIMIT_NOFILE, &rlim); if (unshare(CLONE_NEWNS)) { } if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) { } if (unshare(CLONE_NEWIPC)) { } if (unshare(0x02000000)) { } if (unshare(CLONE_NEWUTS)) { } if (unshare(CLONE_SYSVSEM)) { } typedef struct { const char* name; const char* value; } sysctl_t; static const sysctl_t sysctls[] = { {"/proc/sys/kernel/shmmax", "16777216"}, {"/proc/sys/kernel/shmall", "536870912"}, {"/proc/sys/kernel/shmmni", "1024"}, {"/proc/sys/kernel/msgmax", "8192"}, {"/proc/sys/kernel/msgmni", "1024"}, {"/proc/sys/kernel/msgmnb", "1024"}, {"/proc/sys/kernel/sem", "1024 1048576 500 1024"}, }; unsigned i; for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++) write_file(sysctls[i].name, sysctls[i].value); } static int wait_for_loop(int pid) { if (pid < 0) exit(1); int status = 0; while (waitpid(-1, &status, __WALL) != pid) { } return WEXITSTATUS(status); } static void drop_caps(void) { struct __user_cap_header_struct cap_hdr = {}; struct __user_cap_data_struct cap_data[2] = {}; cap_hdr.version = _LINUX_CAPABILITY_VERSION_3; cap_hdr.pid = getpid(); if (syscall(SYS_capget, &cap_hdr, &cap_data)) exit(1); const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE); cap_data[0].effective &= ~drop; cap_data[0].permitted &= ~drop; cap_data[0].inheritable &= ~drop; if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1); } static int do_sandbox_none(void) { if (unshare(CLONE_NEWPID)) { } int pid = fork(); if (pid != 0) return wait_for_loop(pid); setup_common(); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } setup_binderfs(); loop(); exit(1); } #define FS_IOC_SETFLAGS _IOW('f', 2, long) static void remove_dir(const char* dir) { int iter = 0; DIR* dp = 0; retry: while (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) { } dp = opendir(dir); if (dp == NULL) { if (errno == EMFILE) { exit(1); } exit(1); } struct dirent* ep = 0; 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 | UMOUNT_NOFOLLOW) == 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 | UMOUNT_NOFOLLOW)) exit(1); } } closedir(dp); for (int 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 | UMOUNT_NOFOLLOW)) exit(1); continue; } if (errno == ENOTEMPTY) { if (iter < 100) { iter++; goto retry; } } } exit(1); } } static int inject_fault(int nth) { int fd; fd = open("/proc/thread-self/fail-nth", O_RDWR); if (fd == -1) exit(1); char buf[16]; sprintf(buf, "%d", nth); if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) exit(1); return fd; } 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_loop() { setup_cgroups_loop(); } static void setup_test() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); setup_cgroups_test(); write_file("/proc/self/oom_score_adj", "1000"); if (symlink("/dev/binderfs", "./binderfs")) { } } static void close_fds() { for (int fd = 3; fd < MAX_FDS; fd++) close(fd); } static void setup_fault() { static struct { const char* file; const char* val; bool fatal; } files[] = { {"/sys/kernel/debug/failslab/ignore-gfp-wait", "N", true}, {"/sys/kernel/debug/fail_futex/ignore-private", "N", false}, {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem", "N", false}, {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-wait", "N", false}, {"/sys/kernel/debug/fail_page_alloc/min-order", "0", false}, }; unsigned i; for (i = 0; i < sizeof(files) / sizeof(files[0]); i++) { if (!write_file(files[i].file, files[i].val)) { if (files[i].fatal) exit(1); } } } #define KMEMLEAK_FILE "/sys/kernel/debug/kmemleak" static void setup_leak() { if (!write_file(KMEMLEAK_FILE, "scan")) exit(1); sleep(5); if (!write_file(KMEMLEAK_FILE, "scan")) exit(1); if (!write_file(KMEMLEAK_FILE, "clear")) exit(1); } static void check_leaks(void) { int fd = open(KMEMLEAK_FILE, O_RDWR); if (fd == -1) exit(1); uint64_t start = current_time_ms(); if (write(fd, "scan", 4) != 4) exit(1); sleep(1); while (current_time_ms() - start < 4 * 1000) sleep(1); if (write(fd, "scan", 4) != 4) exit(1); static char buf[128 << 10]; ssize_t n = read(fd, buf, sizeof(buf) - 1); if (n < 0) exit(1); int nleaks = 0; if (n != 0) { sleep(1); if (write(fd, "scan", 4) != 4) exit(1); if (lseek(fd, 0, SEEK_SET) < 0) exit(1); n = read(fd, buf, sizeof(buf) - 1); if (n < 0) exit(1); buf[n] = 0; char* pos = buf; char* end = buf + n; while (pos < end) { char* next = strstr(pos + 1, "unreferenced object"); if (!next) next = end; char prev = *next; *next = 0; fprintf(stderr, "BUG: memory leak\n%s\n", pos); *next = prev; pos = next; nleaks++; } } if (write(fd, "clear", 5) != 5) exit(1); close(fd); if (nleaks) exit(1); } static void execute_one(void); #define WAIT_FLAGS __WALL static void loop(void) { setup_loop(); int iter = 0; for (;; iter++) { char cwdbuf[32]; sprintf(cwdbuf, "./%d", iter); if (mkdir(cwdbuf, 0777)) exit(1); int pid = fork(); if (pid < 0) exit(1); if (pid == 0) { if (chdir(cwdbuf)) exit(1); setup_test(); execute_one(); close_fds(); 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; } remove_dir(cwdbuf); check_leaks(); } } void execute_one(void) { inject_fault(53); syscall(__NR_unshare, 0x8000000ul); } int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); setup_cgroups(); setup_leak(); setup_fault(); use_temporary_dir(); do_sandbox_none(); return 0; }