Syzkaller hit 'memory leak in iov_iter_extract_pages' bug. executing program executing program BUG: memory leak unreferenced object 0xffff88800979c400 (size 256): comm "syz-executor020", pid 249, jiffies 4294809458 (age 21.351s) hex dump (first 32 bytes): 00 22 1f 10 80 88 ff ff d5 00 00 00 19 01 61 07 ."............a. b0 f5 02 bc c3 55 00 00 2d 00 00 00 00 00 00 00 .....U..-....... backtrace: [<00000000b6b30ca9>] __kmalloc_node+0x50/0x160 [<00000000ca2e9bf8>] kvmalloc_node+0xaa/0x200 [<000000000929e47f>] iov_iter_extract_pages+0x353/0x1950 [<00000000614dc266>] bio_map_user_iov+0x2f9/0xa80 [<0000000034678313>] blk_rq_map_user_iov+0x685/0x16c0 [<00000000731d9f89>] blk_rq_map_user_io+0x1d1/0x200 [<000000006c02d75d>] sg_io+0x565/0xd80 [<0000000085010699>] scsi_cdrom_send_packet+0x2aa/0x510 [<0000000064f13670>] scsi_ioctl+0x131/0x15a0 [<0000000021c92ee3>] sr_block_ioctl+0x204/0x250 [<000000004d30271f>] blkdev_ioctl+0x2e4/0x750 [<0000000063cafe65>] __x64_sys_ioctl+0x1a4/0x210 [<000000005f462e07>] do_syscall_64+0x3f/0x90 [<000000004ea8ce6a>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 BUG: memory leak unreferenced object 0xffff88800979c600 (size 256): comm "syz-executor020", pid 250, jiffies 4294818865 (age 11.944s) hex dump (first 32 bytes): 00 80 d8 19 80 88 ff ff d5 00 00 00 19 01 61 07 ..............a. 70 30 0c bc c3 55 00 00 37 00 00 00 00 00 00 00 p0...U..7....... backtrace: [<00000000b6b30ca9>] __kmalloc_node+0x50/0x160 [<00000000ca2e9bf8>] kvmalloc_node+0xaa/0x200 [<000000000929e47f>] iov_iter_extract_pages+0x353/0x1950 [<00000000614dc266>] bio_map_user_iov+0x2f9/0xa80 [<0000000034678313>] blk_rq_map_user_iov+0x685/0x16c0 [<00000000731d9f89>] blk_rq_map_user_io+0x1d1/0x200 [<000000006c02d75d>] sg_io+0x565/0xd80 [<0000000085010699>] scsi_cdrom_send_packet+0x2aa/0x510 [<0000000064f13670>] scsi_ioctl+0x131/0x15a0 [<0000000021c92ee3>] sr_block_ioctl+0x204/0x250 [<000000004d30271f>] blkdev_ioctl+0x2e4/0x750 [<0000000063cafe65>] __x64_sys_ioctl+0x1a4/0x210 [<000000005f462e07>] do_syscall_64+0x3f/0x90 [<000000004ea8ce6a>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 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:false Sysctl:false UseTmpDir:false HandleSegv:false Repro:false Trace:false LegacyOptions:{Fault:false FaultCall:0 FaultNth:0}} r0 = openat$cdrom(0xffffffffffffff9c, &(0x7f0000000080), 0x840, 0x0) ioctl$CDROM_SEND_PACKET(r0, 0x5393, &(0x7f0000000240)={"56aa932c3a2c0f3386d0dab7", 0x0, 0x20000, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0}) 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 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; } 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"); } #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) { 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(); } } uint64_t r[1] = {0xffffffffffffffff}; void execute_one(void) { intptr_t res = 0; memcpy((void*)0x20000080, "/dev/cdrom\000", 11); res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000080ul, 0x840ul, 0ul); if (res != -1) r[0] = res; memcpy((void*)0x20000240, "\x56\xaa\x93\x2c\x3a\x2c\x0f\x33\x86\xd0\xda\xb7", 12); *(uint64_t*)0x20000250 = 0; *(uint32_t*)0x20000258 = 0x20000; *(uint32_t*)0x2000025c = 0; *(uint64_t*)0x20000260 = 0; *(uint8_t*)0x20000268 = 2; *(uint32_t*)0x2000026c = 0; *(uint32_t*)0x20000270 = 0; *(uint64_t*)0x20000278 = 0; syscall(__NR_ioctl, r[0], 0x5393, 0x20000240ul); } 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(); loop(); return 0; }