Syzkaller hit 'memory leak in do_mas_align_munmap' bug. executing program executing program executing program executing program executing program BUG: memory leak unreferenced object 0xffff88801dd58000 (size 256): comm "syz-executor661", pid 287, jiffies 4295024658 (age 22.971s) hex dump (first 32 bytes): 07 00 00 00 00 00 00 00 05 00 00 00 00 00 00 00 ................ 00 82 d5 1d 80 88 ff ff 00 84 d5 1d 80 88 ff ff ................ backtrace: [<000000002a404f62>] mas_alloc_nodes+0x36e/0x6a0 [<000000007a73fd59>] mas_preallocate+0xff/0x270 [<00000000b88d3be0>] do_mas_align_munmap.constprop.0+0x13a/0xff0 [<00000000f2a14a10>] do_mas_munmap+0x1ed/0x2c0 [<00000000b8f9d998>] mmap_region+0x21c/0x1a00 [<000000007c24022b>] do_mmap+0x824/0xf40 [<0000000089f995e9>] vm_mmap_pgoff+0x1b5/0x280 [<00000000022d3363>] ksys_mmap_pgoff+0x3cc/0x4f0 [<000000005ecd5212>] do_syscall_64+0x3b/0x90 [<0000000088fea0cb>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 BUG: memory leak unreferenced object 0xffff88801dd58200 (size 256): comm "syz-executor661", pid 287, jiffies 4295024658 (age 22.971s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000bb444b3d>] mas_alloc_nodes+0x2a6/0x6a0 [<000000007a73fd59>] mas_preallocate+0xff/0x270 [<00000000b88d3be0>] do_mas_align_munmap.constprop.0+0x13a/0xff0 [<00000000f2a14a10>] do_mas_munmap+0x1ed/0x2c0 [<00000000b8f9d998>] mmap_region+0x21c/0x1a00 [<000000007c24022b>] do_mmap+0x824/0xf40 [<0000000089f995e9>] vm_mmap_pgoff+0x1b5/0x280 [<00000000022d3363>] ksys_mmap_pgoff+0x3cc/0x4f0 [<000000005ecd5212>] do_syscall_64+0x3b/0x90 [<0000000088fea0cb>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 BUG: memory leak unreferenced object 0xffff88801dd58400 (size 256): comm "syz-executor661", pid 287, jiffies 4295024658 (age 22.971s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000bb444b3d>] mas_alloc_nodes+0x2a6/0x6a0 [<000000007a73fd59>] mas_preallocate+0xff/0x270 [<00000000b88d3be0>] do_mas_align_munmap.constprop.0+0x13a/0xff0 [<00000000f2a14a10>] do_mas_munmap+0x1ed/0x2c0 [<00000000b8f9d998>] mmap_region+0x21c/0x1a00 [<000000007c24022b>] do_mmap+0x824/0xf40 [<0000000089f995e9>] vm_mmap_pgoff+0x1b5/0x280 [<00000000022d3363>] ksys_mmap_pgoff+0x3cc/0x4f0 [<000000005ecd5212>] do_syscall_64+0x3b/0x90 [<0000000088fea0cb>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 BUG: memory leak unreferenced object 0xffff88801dd58600 (size 256): comm "syz-executor661", pid 287, jiffies 4295024658 (age 22.971s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000bb444b3d>] mas_alloc_nodes+0x2a6/0x6a0 [<000000007a73fd59>] mas_preallocate+0xff/0x270 [<00000000b88d3be0>] do_mas_align_munmap.constprop.0+0x13a/0xff0 [<00000000f2a14a10>] do_mas_munmap+0x1ed/0x2c0 [<00000000b8f9d998>] mmap_region+0x21c/0x1a00 [<000000007c24022b>] do_mmap+0x824/0xf40 [<0000000089f995e9>] vm_mmap_pgoff+0x1b5/0x280 [<00000000022d3363>] ksys_mmap_pgoff+0x3cc/0x4f0 [<000000005ecd5212>] do_syscall_64+0x3b/0x90 [<0000000088fea0cb>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 Syzkaller reproducer: # {Threaded:false Collide:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: Leak:true NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false USB:false VhciInjection:false Wifi:false IEEE802154:true Sysctl:false UseTmpDir:false HandleSegv:false Repro:false Trace:false LegacyOptions:{Fault:false FaultCall:0 FaultNth:0}} syz_io_uring_setup(0x1e58, &(0x7f0000000080)={0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, &(0x7f00000a0000)=nil, &(0x7f00000b0000)=nil, 0x0, 0x0) syz_io_uring_setup(0x3e5b, &(0x7f0000000100), &(0x7f0000ffe000/0x1000)=nil, &(0x7f0000ffb000/0x4000)=nil, 0x0, 0x0) (fail_nth: 55) 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 #include #include #include #include #include #include #include #include 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 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 nlmsg { char* pos; int nesting; struct nlattr* nested[8]; char buf[4096]; }; static void netlink_init(struct nlmsg* nlmsg, int typ, int flags, const void* data, int size) { memset(nlmsg, 0, sizeof(*nlmsg)); struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf; hdr->nlmsg_type = typ; hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags; memcpy(hdr + 1, data, size); nlmsg->pos = (char*)(hdr + 1) + NLMSG_ALIGN(size); } static void netlink_attr(struct nlmsg* nlmsg, int typ, const void* data, int size) { struct nlattr* attr = (struct nlattr*)nlmsg->pos; attr->nla_len = sizeof(*attr) + size; attr->nla_type = typ; if (size > 0) memcpy(attr + 1, data, size); nlmsg->pos += NLMSG_ALIGN(attr->nla_len); } static void netlink_nest(struct nlmsg* nlmsg, int typ) { struct nlattr* attr = (struct nlattr*)nlmsg->pos; attr->nla_type = typ; nlmsg->pos += sizeof(*attr); nlmsg->nested[nlmsg->nesting++] = attr; } static void netlink_done(struct nlmsg* nlmsg) { struct nlattr* attr = nlmsg->nested[--nlmsg->nesting]; attr->nla_len = nlmsg->pos - (char*)attr; } static int netlink_send_ext(struct nlmsg* nlmsg, int sock, uint16_t reply_type, int* reply_len, bool dofail) { if (nlmsg->pos > nlmsg->buf + sizeof(nlmsg->buf) || nlmsg->nesting) exit(1); struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf; hdr->nlmsg_len = nlmsg->pos - nlmsg->buf; struct sockaddr_nl addr; memset(&addr, 0, sizeof(addr)); addr.nl_family = AF_NETLINK; ssize_t n = sendto(sock, nlmsg->buf, hdr->nlmsg_len, 0, (struct sockaddr*)&addr, sizeof(addr)); if (n != (ssize_t)hdr->nlmsg_len) { if (dofail) exit(1); return -1; } n = recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0); if (reply_len) *reply_len = 0; if (n < 0) { if (dofail) exit(1); return -1; } if (n < (ssize_t)sizeof(struct nlmsghdr)) { errno = EINVAL; if (dofail) exit(1); return -1; } if (hdr->nlmsg_type == NLMSG_DONE) return 0; if (reply_len && hdr->nlmsg_type == reply_type) { *reply_len = n; return 0; } if (n < (ssize_t)(sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr))) { errno = EINVAL; if (dofail) exit(1); return -1; } if (hdr->nlmsg_type != NLMSG_ERROR) { errno = EINVAL; if (dofail) exit(1); return -1; } errno = -((struct nlmsgerr*)(hdr + 1))->error; return -errno; } static int netlink_send(struct nlmsg* nlmsg, int sock) { return netlink_send_ext(nlmsg, sock, 0, NULL, true); } static int netlink_query_family_id(struct nlmsg* nlmsg, int sock, const char* family_name, bool dofail) { struct genlmsghdr genlhdr; memset(&genlhdr, 0, sizeof(genlhdr)); genlhdr.cmd = CTRL_CMD_GETFAMILY; netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr)); netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, family_name, strnlen(family_name, GENL_NAMSIZ - 1) + 1); int n = 0; int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n, dofail); if (err < 0) { return -1; } uint16_t id = 0; struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN + NLMSG_ALIGN(sizeof(genlhdr))); for (; (char*)attr < nlmsg->buf + n; attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) { if (attr->nla_type == CTRL_ATTR_FAMILY_ID) { id = *(uint16_t*)(attr + 1); break; } } if (!id) { errno = EINVAL; return -1; } recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0); return id; } static void netlink_add_device_impl(struct nlmsg* nlmsg, const char* type, const char* name) { struct ifinfomsg hdr; memset(&hdr, 0, sizeof(hdr)); netlink_init(nlmsg, RTM_NEWLINK, NLM_F_EXCL | NLM_F_CREATE, &hdr, sizeof(hdr)); if (name) netlink_attr(nlmsg, IFLA_IFNAME, name, strlen(name)); netlink_nest(nlmsg, IFLA_LINKINFO); netlink_attr(nlmsg, IFLA_INFO_KIND, type, strlen(type)); } static void netlink_device_change(struct nlmsg* nlmsg, int sock, const char* name, bool up, const char* master, const void* mac, int macsize, const char* new_name) { struct ifinfomsg hdr; memset(&hdr, 0, sizeof(hdr)); if (up) hdr.ifi_flags = hdr.ifi_change = IFF_UP; hdr.ifi_index = if_nametoindex(name); netlink_init(nlmsg, RTM_NEWLINK, 0, &hdr, sizeof(hdr)); if (new_name) netlink_attr(nlmsg, IFLA_IFNAME, new_name, strlen(new_name)); if (master) { int ifindex = if_nametoindex(master); netlink_attr(nlmsg, IFLA_MASTER, &ifindex, sizeof(ifindex)); } if (macsize) netlink_attr(nlmsg, IFLA_ADDRESS, mac, macsize); int err = netlink_send(nlmsg, sock); if (err < 0) { } } static struct nlmsg nlmsg; #define SIZEOF_IO_URING_SQE 64 #define SIZEOF_IO_URING_CQE 16 #define SQ_HEAD_OFFSET 0 #define SQ_TAIL_OFFSET 64 #define SQ_RING_MASK_OFFSET 256 #define SQ_RING_ENTRIES_OFFSET 264 #define SQ_FLAGS_OFFSET 276 #define SQ_DROPPED_OFFSET 272 #define CQ_HEAD_OFFSET 128 #define CQ_TAIL_OFFSET 192 #define CQ_RING_MASK_OFFSET 260 #define CQ_RING_ENTRIES_OFFSET 268 #define CQ_RING_OVERFLOW_OFFSET 284 #define CQ_FLAGS_OFFSET 280 #define CQ_CQES_OFFSET 320 struct io_sqring_offsets { uint32_t head; uint32_t tail; uint32_t ring_mask; uint32_t ring_entries; uint32_t flags; uint32_t dropped; uint32_t array; uint32_t resv1; uint64_t resv2; }; struct io_cqring_offsets { uint32_t head; uint32_t tail; uint32_t ring_mask; uint32_t ring_entries; uint32_t overflow; uint32_t cqes; uint64_t resv[2]; }; struct io_uring_params { uint32_t sq_entries; uint32_t cq_entries; uint32_t flags; uint32_t sq_thread_cpu; uint32_t sq_thread_idle; uint32_t features; uint32_t resv[4]; struct io_sqring_offsets sq_off; struct io_cqring_offsets cq_off; }; #define IORING_OFF_SQ_RING 0 #define IORING_OFF_SQES 0x10000000ULL #define sys_io_uring_setup 425 static long syz_io_uring_setup(volatile long a0, volatile long a1, volatile long a2, volatile long a3, volatile long a4, volatile long a5) { uint32_t entries = (uint32_t)a0; struct io_uring_params* setup_params = (struct io_uring_params*)a1; void* vma1 = (void*)a2; void* vma2 = (void*)a3; void** ring_ptr_out = (void**)a4; void** sqes_ptr_out = (void**)a5; uint32_t fd_io_uring = syscall(sys_io_uring_setup, entries, setup_params); uint32_t sq_ring_sz = setup_params->sq_off.array + setup_params->sq_entries * sizeof(uint32_t); uint32_t cq_ring_sz = setup_params->cq_off.cqes + setup_params->cq_entries * SIZEOF_IO_URING_CQE; uint32_t ring_sz = sq_ring_sz > cq_ring_sz ? sq_ring_sz : cq_ring_sz; *ring_ptr_out = mmap(vma1, ring_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd_io_uring, IORING_OFF_SQ_RING); uint32_t sqes_sz = setup_params->sq_entries * SIZEOF_IO_URING_SQE; *sqes_ptr_out = mmap(vma2, sqes_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd_io_uring, IORING_OFF_SQES); return fd_io_uring; } 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_test() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); write_file("/proc/self/oom_score_adj", "1000"); } 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); } #define NL802154_CMD_SET_SHORT_ADDR 11 #define NL802154_ATTR_IFINDEX 3 #define NL802154_ATTR_SHORT_ADDR 10 static void setup_802154() { int sock_route = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); if (sock_route == -1) exit(1); int sock_generic = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC); if (sock_generic < 0) exit(1); int nl802154_family_id = netlink_query_family_id(&nlmsg, sock_generic, "nl802154", true); for (int i = 0; i < 2; i++) { char devname[] = "wpan0"; devname[strlen(devname) - 1] += i; uint64_t hwaddr = 0xaaaaaaaaaaaa0002 + (i << 8); uint16_t shortaddr = 0xaaa0 + i; int ifindex = if_nametoindex(devname); struct genlmsghdr genlhdr; memset(&genlhdr, 0, sizeof(genlhdr)); genlhdr.cmd = NL802154_CMD_SET_SHORT_ADDR; netlink_init(&nlmsg, nl802154_family_id, 0, &genlhdr, sizeof(genlhdr)); netlink_attr(&nlmsg, NL802154_ATTR_IFINDEX, &ifindex, sizeof(ifindex)); netlink_attr(&nlmsg, NL802154_ATTR_SHORT_ADDR, &shortaddr, sizeof(shortaddr)); int err = netlink_send(&nlmsg, sock_generic); if (err < 0) { } netlink_device_change(&nlmsg, sock_route, devname, true, 0, &hwaddr, sizeof(hwaddr), 0); if (i == 0) { netlink_add_device_impl(&nlmsg, "lowpan", "lowpan0"); netlink_done(&nlmsg); netlink_attr(&nlmsg, IFLA_LINK, &ifindex, sizeof(ifindex)); int err = netlink_send(&nlmsg, sock_route); if (err < 0) { } } } close(sock_route); close(sock_generic); } 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; } check_leaks(); } } void execute_one(void) { *(uint32_t*)0x20000084 = 0; *(uint32_t*)0x20000088 = 0; *(uint32_t*)0x2000008c = 0; *(uint32_t*)0x20000090 = 0; *(uint32_t*)0x20000098 = 0; memset((void*)0x2000009c, 0, 12); syz_io_uring_setup(0x1e58, 0x20000080, 0x200a0000, 0x200b0000, 0, 0); *(uint32_t*)0x20000104 = 0; *(uint32_t*)0x20000108 = 0; *(uint32_t*)0x2000010c = 0; *(uint32_t*)0x20000110 = 0; *(uint32_t*)0x20000118 = -1; memset((void*)0x2000011c, 0, 12); inject_fault(55); syz_io_uring_setup(0x3e5b, 0x20000100, 0x20ffe000, 0x20ffb000, 0, 0); } 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_leak(); setup_fault(); setup_802154(); loop(); return 0; }