diff options
Diffstat (limited to 'arch/um/os-Linux')
| -rw-r--r-- | arch/um/os-Linux/Makefile | 2 | ||||
| -rw-r--r-- | arch/um/os-Linux/file.c | 6 | ||||
| -rw-r--r-- | arch/um/os-Linux/main.c | 23 | ||||
| -rw-r--r-- | arch/um/os-Linux/mem.c | 14 | ||||
| -rw-r--r-- | arch/um/os-Linux/process.c | 88 | ||||
| -rw-r--r-- | arch/um/os-Linux/registers.c | 11 | ||||
| -rw-r--r-- | arch/um/os-Linux/sigio.c | 1 | ||||
| -rw-r--r-- | arch/um/os-Linux/signal.c | 55 | ||||
| -rw-r--r-- | arch/um/os-Linux/skas/mem.c | 21 | ||||
| -rw-r--r-- | arch/um/os-Linux/skas/process.c | 231 | ||||
| -rw-r--r-- | arch/um/os-Linux/umid.c | 2 | ||||
| -rw-r--r-- | arch/um/os-Linux/util.c | 4 |
12 files changed, 214 insertions, 244 deletions
diff --git a/arch/um/os-Linux/Makefile b/arch/um/os-Linux/Makefile index 544e0b344c75..049dfa5bc9c6 100644 --- a/arch/um/os-Linux/Makefile +++ b/arch/um/os-Linux/Makefile @@ -12,6 +12,8 @@ obj-y = execvp.o file.o helper.o irq.o main.o mem.o process.o \ CFLAGS_signal.o += -Wframe-larger-than=4096 +CFLAGS_main.o += -Wno-frame-larger-than + obj-$(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) += elf_aux.o USER_OBJS := $(user-objs-y) elf_aux.o execvp.o file.o helper.o irq.o \ diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c index f1d03cf3957f..a0d01c68ce3e 100644 --- a/arch/um/os-Linux/file.c +++ b/arch/um/os-Linux/file.c @@ -255,12 +255,6 @@ void os_close_file(int fd) { close(fd); } -int os_fsync_file(int fd) -{ - if (fsync(fd) < 0) - return -errno; - return 0; -} int os_seek_file(int fd, unsigned long long offset) { diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c index f98ff79cdbf7..0afcdeb8995b 100644 --- a/arch/um/os-Linux/main.c +++ b/arch/um/os-Linux/main.c @@ -11,6 +11,7 @@ #include <signal.h> #include <string.h> #include <sys/resource.h> +#include <sys/personality.h> #include <as-layout.h> #include <init.h> #include <kern_util.h> @@ -108,6 +109,21 @@ int __init main(int argc, char **argv, char **envp) char **new_argv; int ret, i, err; + /* Disable randomization and re-exec if it was changed successfully */ + ret = personality(PER_LINUX | ADDR_NO_RANDOMIZE); + if (ret >= 0 && (ret & (PER_LINUX | ADDR_NO_RANDOMIZE)) != + (PER_LINUX | ADDR_NO_RANDOMIZE)) { + char buf[4096] = {}; + ssize_t ret; + + ret = readlink("/proc/self/exe", buf, sizeof(buf)); + if (ret < 0 || ret >= sizeof(buf)) { + perror("readlink failure"); + exit(1); + } + execve(buf, argv, envp); + } + set_stklim(); setup_env_path(); @@ -140,7 +156,7 @@ int __init main(int argc, char **argv, char **envp) #endif change_sig(SIGPIPE, 0); - ret = linux_main(argc, argv); + ret = linux_main(argc, argv, envp); /* * Disable SIGPROF - I have no idea why libc doesn't do this or turn @@ -182,6 +198,7 @@ int __init main(int argc, char **argv, char **envp) } extern void *__real_malloc(int); +extern void __real_free(void *); /* workaround for -Wmissing-prototypes warnings */ void *__wrap_malloc(int size); @@ -219,10 +236,6 @@ void *__wrap_calloc(int n, int size) return ptr; } -extern void __real_free(void *); - -extern unsigned long high_physmem; - void __wrap_free(void *ptr) { unsigned long addr = (unsigned long) ptr; diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c index cf44d386f23c..72f302f4d197 100644 --- a/arch/um/os-Linux/mem.c +++ b/arch/um/os-Linux/mem.c @@ -39,10 +39,22 @@ void kasan_map_memory(void *start, size_t len) strerror(errno)); exit(1); } + + if (madvise(start, len, MADV_DONTDUMP)) { + os_info("Couldn't set MAD_DONTDUMP on shadow memory: %s\n.", + strerror(errno)); + exit(1); + } + + if (madvise(start, len, MADV_DONTFORK)) { + os_info("Couldn't set MADV_DONTFORK on shadow memory: %s\n.", + strerror(errno)); + exit(1); + } } /* Set by make_tempfile() during early boot. */ -static char *tempdir = NULL; +char *tempdir = NULL; /* Check if dir is on tmpfs. Return 0 if yes, -1 if no or error. */ static int __init check_tmpfs(const char *dir) diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c index e52dd37ddadc..9f086f939420 100644 --- a/arch/um/os-Linux/process.c +++ b/arch/um/os-Linux/process.c @@ -12,94 +12,18 @@ #include <fcntl.h> #include <sys/mman.h> #include <sys/ptrace.h> +#include <sys/prctl.h> #include <sys/wait.h> #include <asm/unistd.h> #include <init.h> #include <longjmp.h> #include <os.h> -#define ARBITRARY_ADDR -1 -#define FAILURE_PID -1 - -#define STAT_PATH_LEN sizeof("/proc/#######/stat\0") -#define COMM_SCANF "%*[^)])" - -unsigned long os_process_pc(int pid) -{ - char proc_stat[STAT_PATH_LEN], buf[256]; - unsigned long pc = ARBITRARY_ADDR; - int fd, err; - - sprintf(proc_stat, "/proc/%d/stat", pid); - fd = open(proc_stat, O_RDONLY, 0); - if (fd < 0) { - printk(UM_KERN_ERR "os_process_pc - couldn't open '%s', " - "errno = %d\n", proc_stat, errno); - goto out; - } - CATCH_EINTR(err = read(fd, buf, sizeof(buf))); - if (err < 0) { - printk(UM_KERN_ERR "os_process_pc - couldn't read '%s', " - "err = %d\n", proc_stat, errno); - goto out_close; - } - os_close_file(fd); - pc = ARBITRARY_ADDR; - if (sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d " - "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d " - "%*d %*d %*d %*d %*d %lu", &pc) != 1) - printk(UM_KERN_ERR "os_process_pc - couldn't find pc in '%s'\n", - buf); - out_close: - close(fd); - out: - return pc; -} - -int os_process_parent(int pid) -{ - char stat[STAT_PATH_LEN]; - char data[256]; - int parent = FAILURE_PID, n, fd; - - if (pid == -1) - return parent; - - snprintf(stat, sizeof(stat), "/proc/%d/stat", pid); - fd = open(stat, O_RDONLY, 0); - if (fd < 0) { - printk(UM_KERN_ERR "Couldn't open '%s', errno = %d\n", stat, - errno); - return parent; - } - - CATCH_EINTR(n = read(fd, data, sizeof(data))); - close(fd); - - if (n < 0) { - printk(UM_KERN_ERR "Couldn't read '%s', errno = %d\n", stat, - errno); - return parent; - } - - parent = FAILURE_PID; - n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent); - if (n != 1) - printk(UM_KERN_ERR "Failed to scan '%s'\n", data); - - return parent; -} - void os_alarm_process(int pid) { kill(pid, SIGALRM); } -void os_stop_process(int pid) -{ - kill(pid, SIGSTOP); -} - void os_kill_process(int pid, int reap_child) { kill(pid, SIGKILL); @@ -130,11 +54,6 @@ int os_getpid(void) return syscall(__NR_getpid); } -int os_getpgrp(void) -{ - return getpgrp(); -} - int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len, int r, int w, int x) { @@ -285,3 +204,8 @@ void init_new_thread_signals(void) set_handler(SIGIO); signal(SIGWINCH, SIG_IGN); } + +void os_set_pdeathsig(void) +{ + prctl(PR_SET_PDEATHSIG, SIGKILL); +} diff --git a/arch/um/os-Linux/registers.c b/arch/um/os-Linux/registers.c index bd80b921add0..d7ca148807b2 100644 --- a/arch/um/os-Linux/registers.c +++ b/arch/um/os-Linux/registers.c @@ -10,11 +10,12 @@ #include <sysdep/ptrace.h> #include <sysdep/ptrace_user.h> #include <registers.h> +#include <stdlib.h> /* This is set once at boot time and not changed thereafter */ static unsigned long exec_regs[MAX_REG_NR]; -static unsigned long exec_fp_regs[FP_SIZE]; +static unsigned long *exec_fp_regs; int init_pid_registers(int pid) { @@ -24,7 +25,11 @@ int init_pid_registers(int pid) if (err < 0) return -errno; - arch_init_registers(pid); + err = arch_init_registers(pid); + if (err < 0) + return err; + + exec_fp_regs = malloc(host_fp_size); get_fp_registers(pid, exec_fp_regs); return 0; } @@ -34,5 +39,5 @@ void get_safe_registers(unsigned long *regs, unsigned long *fp_regs) memcpy(regs, exec_regs, sizeof(exec_regs)); if (fp_regs) - memcpy(fp_regs, exec_fp_regs, sizeof(exec_fp_regs)); + memcpy(fp_regs, exec_fp_regs, host_fp_size); } diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c index 9e71794839e8..9aac8def4d63 100644 --- a/arch/um/os-Linux/sigio.c +++ b/arch/um/os-Linux/sigio.c @@ -55,6 +55,7 @@ static int write_sigio_thread(void *unused) int i, n, respond_fd; char c; + os_set_pdeathsig(); os_fix_helper_signals(); fds = ¤t_poll; while (1) { diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c index b11ed66c8bb0..9ea7269ffb77 100644 --- a/arch/um/os-Linux/signal.c +++ b/arch/um/os-Linux/signal.c @@ -26,7 +26,7 @@ void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = { [SIGFPE] = relay_signal, [SIGILL] = relay_signal, [SIGWINCH] = winch, - [SIGBUS] = bus_handler, + [SIGBUS] = relay_signal, [SIGSEGV] = segv_handler, [SIGIO] = sigio_handler, }; @@ -65,7 +65,7 @@ static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc) #define SIGALRM_MASK (1 << SIGALRM_BIT) int signals_enabled; -#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT +#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT) static int signals_blocked, signals_blocked_pending; #endif static unsigned int signals_pending; @@ -75,7 +75,7 @@ static void sig_handler(int sig, struct siginfo *si, mcontext_t *mc) { int enabled = signals_enabled; -#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT +#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT) if ((signals_blocked || __atomic_load_n(&signals_blocked_pending, __ATOMIC_SEQ_CST)) && (sig == SIGIO)) { @@ -190,43 +190,8 @@ static void hard_handler(int sig, siginfo_t *si, void *p) { ucontext_t *uc = p; mcontext_t *mc = &uc->uc_mcontext; - unsigned long pending = 1UL << sig; - do { - int nested, bail; - - /* - * pending comes back with one bit set for each - * interrupt that arrived while setting up the stack, - * plus a bit for this interrupt, plus the zero bit is - * set if this is a nested interrupt. - * If bail is true, then we interrupted another - * handler setting up the stack. In this case, we - * have to return, and the upper handler will deal - * with this interrupt. - */ - bail = to_irq_stack(&pending); - if (bail) - return; - - nested = pending & 1; - pending &= ~1; - - while ((sig = ffs(pending)) != 0){ - sig--; - pending &= ~(1 << sig); - (*handlers[sig])(sig, (struct siginfo *)si, mc); - } - - /* - * Again, pending comes back with a mask of signals - * that arrived while tearing down the stack. If this - * is non-zero, we just go back, set up the stack - * again, and handle the new interrupts. - */ - if (!nested) - pending = from_irq_stack(nested); - } while (pending); + (*handlers[sig])(sig, (struct siginfo *)si, mc); } void set_handler(int sig) @@ -297,7 +262,7 @@ void unblock_signals(void) return; signals_enabled = 1; -#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT +#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT) deliver_time_travel_irqs(); #endif @@ -389,7 +354,7 @@ int um_set_signals_trace(int enable) return ret; } -#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT +#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT) void mark_sigio_pending(void) { /* @@ -487,11 +452,3 @@ void unblock_signals_hard(void) unblocking = false; } #endif - -int os_is_signal_stack(void) -{ - stack_t ss; - sigaltstack(NULL, &ss); - - return ss.ss_flags & SS_ONSTACK; -} diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c index 9a13ac23c606..d7f1814b0e5a 100644 --- a/arch/um/os-Linux/skas/mem.c +++ b/arch/um/os-Linux/skas/mem.c @@ -217,24 +217,3 @@ int unmap(struct mm_id *mm_idp, unsigned long addr, unsigned long len) return 0; } - -int protect(struct mm_id *mm_idp, unsigned long addr, unsigned long len, - unsigned int prot) -{ - struct stub_syscall *sc; - - /* Compress with previous syscall if that is possible */ - sc = syscall_stub_get_previous(mm_idp, STUB_SYSCALL_MPROTECT, addr); - if (sc && sc->mem.prot == prot) { - sc->mem.length += len; - return 0; - } - - sc = syscall_stub_alloc(mm_idp); - sc->syscall = STUB_SYSCALL_MPROTECT; - sc->mem.addr = addr; - sc->mem.length = len; - sc->mem.prot = prot; - - return 0; -} diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index b6f656bcffb1..f683cfc9e51a 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -10,8 +10,11 @@ #include <sched.h> #include <errno.h> #include <string.h> +#include <fcntl.h> +#include <mem_user.h> #include <sys/mman.h> #include <sys/wait.h> +#include <sys/stat.h> #include <asm/unistd.h> #include <as-layout.h> #include <init.h> @@ -141,16 +144,10 @@ bad_wait: extern unsigned long current_stub_stack(void); -static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux_fp_regs) +static void get_skas_faultinfo(int pid, struct faultinfo *fi) { int err; - err = get_fp_registers(pid, aux_fp_regs); - if (err < 0) { - printk(UM_KERN_ERR "save_fp_registers returned %d\n", - err); - fatal_sigsegv(); - } err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV); if (err) { printk(UM_KERN_ERR "Failed to continue stub, pid = %d, " @@ -164,18 +161,11 @@ static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux * the stub stack page. We just have to copy it. */ memcpy(fi, (void *)current_stub_stack(), sizeof(*fi)); - - err = put_fp_registers(pid, aux_fp_regs); - if (err < 0) { - printk(UM_KERN_ERR "put_fp_registers returned %d\n", - err); - fatal_sigsegv(); - } } -static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp_regs) +static void handle_segv(int pid, struct uml_pt_regs *regs) { - get_skas_faultinfo(pid, ®s->faultinfo, aux_fp_regs); + get_skas_faultinfo(pid, ®s->faultinfo); segv(regs->faultinfo, 0, 1, NULL); } @@ -189,69 +179,131 @@ static void handle_trap(int pid, struct uml_pt_regs *regs) extern char __syscall_stub_start[]; -/** - * userspace_tramp() - userspace trampoline - * @stack: pointer to the new userspace stack page - * - * The userspace trampoline is used to setup a new userspace process in start_userspace() after it was clone()'ed. - * This function will run on a temporary stack page. - * It ptrace()'es itself, then - * Two pages are mapped into the userspace address space: - * - STUB_CODE (with EXEC), which contains the skas stub code - * - STUB_DATA (with R/W), which contains a data page that is used to transfer certain data between the UML userspace process and the UML kernel. - * Also for the userspace process a SIGSEGV handler is installed to catch pagefaults in the userspace process. - * And last the process stops itself to give control to the UML kernel for this userspace process. - * - * Return: Always zero, otherwise the current userspace process is ended with non null exit() call - */ +static int stub_exe_fd; + static int userspace_tramp(void *stack) { - struct sigaction sa; - void *addr; - int fd; + char *const argv[] = { "uml-userspace", NULL }; + int pipe_fds[2]; unsigned long long offset; - unsigned long segv_handler = STUB_CODE + - (unsigned long) stub_segv_handler - - (unsigned long) __syscall_stub_start; - - ptrace(PTRACE_TRACEME, 0, 0, 0); - - signal(SIGTERM, SIG_DFL); - signal(SIGWINCH, SIG_IGN); - - fd = phys_mapping(uml_to_phys(__syscall_stub_start), &offset); - addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE, - PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset); - if (addr == MAP_FAILED) { - os_info("mapping mmap stub at 0x%lx failed, errno = %d\n", - STUB_CODE, errno); - exit(1); + struct stub_init_data init_data = { + .stub_start = STUB_START, + .segv_handler = STUB_CODE + + (unsigned long) stub_segv_handler - + (unsigned long) __syscall_stub_start, + }; + struct iomem_region *iomem; + int ret; + + init_data.stub_code_fd = phys_mapping(uml_to_phys(__syscall_stub_start), + &offset); + init_data.stub_code_offset = MMAP_OFFSET(offset); + + init_data.stub_data_fd = phys_mapping(uml_to_phys(stack), &offset); + init_data.stub_data_offset = MMAP_OFFSET(offset); + + /* Set CLOEXEC on all FDs and then unset on all memory related FDs */ + close_range(0, ~0U, CLOSE_RANGE_CLOEXEC); + + fcntl(init_data.stub_data_fd, F_SETFD, 0); + for (iomem = iomem_regions; iomem; iomem = iomem->next) + fcntl(iomem->fd, F_SETFD, 0); + + /* Create a pipe for init_data (no CLOEXEC) and dup2 to STDIN */ + if (pipe(pipe_fds)) + exit(2); + + if (dup2(pipe_fds[0], 0) < 0) + exit(3); + close(pipe_fds[0]); + + /* Write init_data and close write side */ + ret = write(pipe_fds[1], &init_data, sizeof(init_data)); + close(pipe_fds[1]); + + if (ret != sizeof(init_data)) + exit(4); + + execveat(stub_exe_fd, "", argv, NULL, AT_EMPTY_PATH); + + exit(5); +} + +extern char stub_exe_start[]; +extern char stub_exe_end[]; + +extern char *tempdir; + +#define STUB_EXE_NAME_TEMPLATE "/uml-userspace-XXXXXX" + +#ifndef MFD_EXEC +#define MFD_EXEC 0x0010U +#endif + +static int __init init_stub_exe_fd(void) +{ + size_t written = 0; + char *tmpfile = NULL; + + stub_exe_fd = memfd_create("uml-userspace", + MFD_EXEC | MFD_CLOEXEC | MFD_ALLOW_SEALING); + + if (stub_exe_fd < 0) { + printk(UM_KERN_INFO "Could not create executable memfd, using temporary file!"); + + tmpfile = malloc(strlen(tempdir) + + strlen(STUB_EXE_NAME_TEMPLATE) + 1); + if (tmpfile == NULL) + panic("Failed to allocate memory for stub binary name"); + + strcpy(tmpfile, tempdir); + strcat(tmpfile, STUB_EXE_NAME_TEMPLATE); + + stub_exe_fd = mkstemp(tmpfile); + if (stub_exe_fd < 0) + panic("Could not create temporary file for stub binary: %d", + -errno); } - fd = phys_mapping(uml_to_phys(stack), &offset); - addr = mmap((void *) STUB_DATA, - STUB_DATA_PAGES * UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE, - MAP_FIXED | MAP_SHARED, fd, offset); - if (addr == MAP_FAILED) { - os_info("mapping segfault stack at 0x%lx failed, errno = %d\n", - STUB_DATA, errno); - exit(1); + while (written < stub_exe_end - stub_exe_start) { + ssize_t res = write(stub_exe_fd, stub_exe_start + written, + stub_exe_end - stub_exe_start - written); + if (res < 0) { + if (errno == EINTR) + continue; + + if (tmpfile) + unlink(tmpfile); + panic("Failed write stub binary: %d", -errno); + } + + written += res; } - set_sigstack((void *) STUB_DATA, STUB_DATA_PAGES * UM_KERN_PAGE_SIZE); - sigemptyset(&sa.sa_mask); - sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO; - sa.sa_sigaction = (void *) segv_handler; - sa.sa_restorer = NULL; - if (sigaction(SIGSEGV, &sa, NULL) < 0) { - os_info("%s - setting SIGSEGV handler failed - errno = %d\n", - __func__, errno); - exit(1); + if (!tmpfile) { + fcntl(stub_exe_fd, F_ADD_SEALS, + F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_SEAL); + } else { + if (fchmod(stub_exe_fd, 00500) < 0) { + unlink(tmpfile); + panic("Could not make stub binary executable: %d", + -errno); + } + + close(stub_exe_fd); + stub_exe_fd = open(tmpfile, O_RDONLY | O_CLOEXEC | O_NOFOLLOW); + if (stub_exe_fd < 0) { + unlink(tmpfile); + panic("Could not reopen stub binary: %d", -errno); + } + + unlink(tmpfile); + free(tmpfile); } - kill(os_getpid(), SIGSTOP); return 0; } +__initcall(init_stub_exe_fd); int userspace_pid[NR_CPUS]; @@ -270,7 +322,7 @@ int start_userspace(unsigned long stub_stack) { void *stack; unsigned long sp; - int pid, status, n, flags, err; + int pid, status, n, err; /* setup a temporary stack page */ stack = mmap(NULL, UM_KERN_PAGE_SIZE, @@ -286,10 +338,10 @@ int start_userspace(unsigned long stub_stack) /* set stack pointer to the end of the stack page, so it can grow downwards */ sp = (unsigned long)stack + UM_KERN_PAGE_SIZE; - flags = CLONE_FILES | SIGCHLD; - /* clone into new userspace process */ - pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); + pid = clone(userspace_tramp, (void *) sp, + CLONE_VFORK | CLONE_VM | SIGCHLD, + (void *)stub_stack); if (pid < 0) { err = -errno; printk(UM_KERN_ERR "%s : clone failed, errno = %d\n", @@ -336,7 +388,10 @@ int start_userspace(unsigned long stub_stack) return err; } -void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs) +int unscheduled_userspace_iterations; +extern unsigned long tt_extra_sched_jiffies; + +void userspace(struct uml_pt_regs *regs) { int err, status, op, pid = userspace_pid[0]; siginfo_t si; @@ -345,6 +400,29 @@ void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs) interrupt_end(); while (1) { + /* + * When we are in time-travel mode, userspace can theoretically + * do a *lot* of work without being scheduled. The problem with + * this is that it will prevent kernel bookkeeping (primarily + * the RCU) from running and this can for example cause OOM + * situations. + * + * This code accounts a jiffie against the scheduling clock + * after the defined userspace iterations in the same thread. + * By doing so the situation is effectively prevented. + */ + if (time_travel_mode == TT_MODE_INFCPU || + time_travel_mode == TT_MODE_EXTERNAL) { +#ifdef CONFIG_UML_MAX_USERSPACE_ITERATIONS + if (CONFIG_UML_MAX_USERSPACE_ITERATIONS && + unscheduled_userspace_iterations++ > + CONFIG_UML_MAX_USERSPACE_ITERATIONS) { + tt_extra_sched_jiffies += 1; + unscheduled_userspace_iterations = 0; + } +#endif + } + time_travel_print_bc_msg(); current_mm_sync(); @@ -435,11 +513,11 @@ void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs) case SIGSEGV: if (PTRACE_FULL_FAULTINFO) { get_skas_faultinfo(pid, - ®s->faultinfo, aux_fp_regs); + ®s->faultinfo); (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si, regs); } - else handle_segv(pid, regs, aux_fp_regs); + else handle_segv(pid, regs); break; case SIGTRAP + 0x80: handle_trap(pid, regs); @@ -487,6 +565,8 @@ void new_thread(void *stack, jmp_buf *buf, void (*handler)(void)) void switch_threads(jmp_buf *me, jmp_buf *you) { + unscheduled_userspace_iterations = 0; + if (UML_SETJMP(me) == 0) UML_LONGJMP(you, 1); } @@ -570,6 +650,7 @@ static bool noreboot; static int __init noreboot_cmd_param(char *str, int *add) { + *add = 0; noreboot = true; return 0; } diff --git a/arch/um/os-Linux/umid.c b/arch/um/os-Linux/umid.c index e09d65b05d1c..eb523ab1e218 100644 --- a/arch/um/os-Linux/umid.c +++ b/arch/um/os-Linux/umid.c @@ -358,6 +358,8 @@ char *get_umid(void) static int __init set_uml_dir(char *name, int *add) { + *add = 0; + if (*name == '\0') { os_warn("uml_dir can't be an empty string\n"); return 0; diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c index 1dca4ffbd572..4193e04d7e4a 100644 --- a/arch/um/os-Linux/util.c +++ b/arch/um/os-Linux/util.c @@ -52,8 +52,8 @@ void setup_machinename(char *machine_out) struct utsname host; uname(&host); -#ifdef UML_CONFIG_UML_X86 -# ifndef UML_CONFIG_64BIT +#if IS_ENABLED(CONFIG_UML_X86) +# if !IS_ENABLED(CONFIG_64BIT) if (!strcmp(host.machine, "x86_64")) { strcpy(machine_out, "i686"); return; |