Hi! I've got the following error report while running the syzkaller fuzzer.
On commit a121103c922847ba5010819a3f250f1f7fc84ab8 (4.10-rc3). A reproducer is attached. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 4114 at kernel/sched/core.c:7737 __might_sleep+0x149/0x1a0 do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff813fcb22>] prepare_to_wait+0x182/0x530 Modules linked in: CPU: 0 PID: 4114 Comm: a.out Not tainted 4.10.0-rc3+ #59 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:15 dump_stack+0x292/0x398 lib/dump_stack.c:51 __warn+0x19f/0x1e0 kernel/panic.c:547 warn_slowpath_fmt+0xc5/0x110 kernel/panic.c:562 __might_sleep+0x149/0x1a0 kernel/sched/core.c:7732 slab_pre_alloc_hook mm/slab.h:408 slab_alloc_node mm/slub.c:2634 kmem_cache_alloc_node+0x14a/0x280 mm/slub.c:2744 __alloc_skb+0x10f/0x800 net/core/skbuff.c:219 alloc_skb ./include/linux/skbuff.h:926 alloc_tx net/atm/common.c:75 vcc_sendmsg+0x5e8/0x1010 net/atm/common.c:609 sock_sendmsg_nosec net/socket.c:635 sock_sendmsg+0xca/0x110 net/socket.c:645 ___sys_sendmsg+0x9d2/0xae0 net/socket.c:1985 __sys_sendmsg+0x138/0x320 net/socket.c:2019 SYSC_sendmsg net/socket.c:2030 SyS_sendmsg+0x2d/0x50 net/socket.c:2026 entry_SYSCALL_64_fastpath+0x1f/0xc2 arch/x86/entry/entry_64.S:203 RIP: 0033:0x7fcbacfddb79 RSP: 002b:00007ffed8b5a7b8 EFLAGS: 00000206 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ffed8b5a950 RCX: 00007fcbacfddb79 RDX: 000000000000c000 RSI: 0000000020002000 RDI: 0000000000000003 RBP: 0000000000400af0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007ffed8b5a950 R14: 0000000000000000 R15: 0000000000000000 ---[ end trace 9edf2da84d8112da ]--- atm:sigd_send: bad message type 0
// autogenerated by syzkaller (http://github.com/google/syzkaller) #ifndef __NR_mmap #define __NR_mmap 9 #endif #ifndef __NR_socket #define __NR_socket 41 #endif #ifndef __NR_ioctl #define __NR_ioctl 16 #endif #ifndef __NR_sendmsg #define __NR_sendmsg 46 #endif #define _GNU_SOURCE #include <sys/ioctl.h> #include <sys/mman.h> #include <sys/mount.h> #include <sys/prctl.h> #include <sys/resource.h> #include <sys/socket.h> #include <sys/stat.h> #include <sys/syscall.h> #include <sys/time.h> #include <sys/types.h> #include <sys/wait.h> #include <linux/capability.h> #include <linux/if.h> #include <linux/if_tun.h> #include <linux/sched.h> #include <net/if_arp.h> #include <assert.h> #include <dirent.h> #include <errno.h> #include <fcntl.h> #include <grp.h> #include <pthread.h> #include <setjmp.h> #include <signal.h> #include <stdarg.h> #include <stdbool.h> #include <stddef.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> const int kFailStatus = 67; const int kErrorStatus = 68; const int kRetryStatus = 69; __attribute__((noreturn)) void doexit(int status) { syscall(__NR_exit_group, status); volatile unsigned i; for (i = 0;; i++) { } } __attribute__((noreturn)) void fail(const char* msg, ...) { int e = errno; fflush(stdout); va_list args; va_start(args, msg); vfprintf(stderr, msg, args); va_end(args); fprintf(stderr, " (errno %d)\n", e); doexit(e == ENOMEM ? kRetryStatus : kFailStatus); } __attribute__((noreturn)) void exitf(const char* msg, ...) { int e = errno; fflush(stdout); va_list args; va_start(args, msg); vfprintf(stderr, msg, args); va_end(args); fprintf(stderr, " (errno %d)\n", e); doexit(kRetryStatus); } static int flag_debug; void debug(const char* msg, ...) { if (!flag_debug) return; va_list args; va_start(args, msg); vfprintf(stdout, msg, args); va_end(args); fflush(stdout); } __thread int skip_segv; __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* uctx) { if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED)) _longjmp(segv_env, 1); doexit(sig); for (;;) { } } static void install_segv_handler() { struct sigaction sa; 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 uintptr_t execute_syscall(int nr, uintptr_t a0, uintptr_t a1, uintptr_t a2, uintptr_t a3, uintptr_t a4, uintptr_t a5, uintptr_t a6, uintptr_t a7, uintptr_t a8) { switch (nr) { default: return syscall(nr, a0, a1, a2, a3, a4, a5); } } static void setup_main_process(uint64_t pid, bool enable_tun) { 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); install_segv_handler(); char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) fail("failed to mkdtemp"); if (chmod(tmpdir, 0777)) fail("failed to chmod"); if (chdir(tmpdir)) fail("failed to chdir"); } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); setsid(); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = 128 << 20; setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 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); unshare(CLONE_NEWNS); unshare(CLONE_NEWIPC); unshare(CLONE_IO); } static int do_sandbox_none() { int pid = fork(); if (pid) return pid; sandbox_common(); loop(); doexit(1); } long r[11]; void loop() { memset(r, -1, sizeof(r)); r[0] = execute_syscall(__NR_mmap, 0x20000000ul, 0x4000ul, 0x3ul, 0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0); r[1] = execute_syscall(__NR_socket, 0x8ul, 0x0ul, 0x0ul, 0, 0, 0, 0, 0, 0); r[2] = execute_syscall(__NR_ioctl, r[1], 0x61f0ul, 0x20003000ul, 0, 0, 0, 0, 0, 0); NONFAILING(*(uint64_t*)0x20002000 = (uint64_t)0x0); NONFAILING(*(uint32_t*)0x20002008 = (uint32_t)0x0); NONFAILING(*(uint64_t*)0x20002010 = (uint64_t)0x20002000); NONFAILING(*(uint64_t*)0x20002018 = (uint64_t)0x2); NONFAILING(*(uint64_t*)0x20002020 = (uint64_t)0x0); NONFAILING(*(uint64_t*)0x20002028 = (uint64_t)0x0); NONFAILING(*(uint32_t*)0x20002030 = (uint32_t)0x0); r[10] = execute_syscall(__NR_sendmsg, r[1], 0x20002000ul, 0xc000ul, 0, 0, 0, 0, 0, 0); } int main() { setup_main_process(0, false); int pid = do_sandbox_none(); int status = 0; while (waitpid(pid, &status, __WALL) != pid) { } return 0; }
