On Fri, Jul 06, 2007 at 10:30:19AM -0700, Dan Kegel wrote: > Could you give it a shot?
OK, after ripping out the code that broke valgrind last time (patch below), I get this: ==27590== Warning: set address range perms: large range 516194304, a 0, v 0 vex x86->IR: unhandled instruction bytes: 0xF3 0xAF 0x74 0x9 ==27590== Your program just tried to execute an instruction that Valgrind ==27590== did not recognise. There are two possible reasons for this. ==27590== 1. Your program has a bug and erroneously jumped to a non-code ==27590== location. If you are running Memcheck and you just saw a ==27590== warning about a bad jump, it's probably your program's fault. ==27590== 2. The instruction is legitimate but Valgrind doesn't handle it, ==27590== i.e. it's Valgrind's fault. If you think this is the case or ==27590== you are not sure, please let us know. ==27590== Either way, Valgrind will now raise a SIGILL signal which will ==27590== probably kill your program. ==27590== > Maybe the problems after that will be more pedestrian. Doesn't look like it. FWIW, that instruction is repz scas. In an earlier valgrind effort in 2002, I hit repe scas (http://www.goop.org/~jeremy/valgrind/76-repe-scas.patch), so maybe something similar is needed here. > I'm willing to focus a little effort on this. I guess you'll have to fix valgrind's various bugs. See, simple :) Jeff -- Work email - jdike at linux dot intel dot com Index: linux-2.6.21-mm/arch/um/os-Linux/start_up.c =================================================================== --- linux-2.6.21-mm.orig/arch/um/os-Linux/start_up.c 2007-07-02 21:11:33.000000000 -0400 +++ linux-2.6.21-mm/arch/um/os-Linux/start_up.c 2007-07-06 15:16:47.000000000 -0400 @@ -43,54 +43,6 @@ #include "registers.h" #endif -static int ptrace_child(void *arg) -{ - int ret; - int pid = os_getpid(), ppid = getppid(); - int sc_result; - - change_sig(SIGWINCH, 0); - if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){ - perror("ptrace"); - os_kill_process(pid, 0); - } - kill(pid, SIGSTOP); - - /*This syscall will be intercepted by the parent. Don't call more than - * once, please.*/ - sc_result = os_getpid(); - - if (sc_result == pid) - ret = 1; /*Nothing modified by the parent, we are running - normally.*/ - else if (sc_result == ppid) - ret = 0; /*Expected in check_ptrace and check_sysemu when they - succeed in modifying the stack frame*/ - else - ret = 2; /*Serious trouble! This could be caused by a bug in - host 2.6 SKAS3/2.6 patch before release -V6, together - with a bug in the UML code itself.*/ - _exit(ret); -} - -static void fatal_perror(char *str) -{ - perror(str); - exit(1); -} - -static void fatal(char *fmt, ...) -{ - va_list list; - - va_start(list, fmt); - vprintf(fmt, list); - va_end(list); - fflush(stdout); - - exit(1); -} - static void non_fatal(char *fmt, ...) { va_list list; @@ -101,64 +53,6 @@ static void non_fatal(char *fmt, ...) fflush(stdout); } -static int start_ptraced_child(void **stack_out) -{ - void *stack; - unsigned long sp; - int pid, n, status; - - stack = mmap(NULL, UM_KERN_PAGE_SIZE, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - if(stack == MAP_FAILED) - fatal_perror("check_ptrace : mmap failed"); - sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *); - pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL); - if(pid < 0) - fatal_perror("start_ptraced_child : clone failed"); - CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); - if(n < 0) - fatal_perror("check_ptrace : clone failed"); - if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) - fatal("check_ptrace : expected SIGSTOP, got status = %d", - status); - - *stack_out = stack; - return pid; -} - -/* When testing for SYSEMU support, if it is one of the broken versions, we - * must just avoid using sysemu, not panic, but only if SYSEMU features are - * broken. - * So only for SYSEMU features we test mustpanic, while normal host features - * must work anyway! - */ -static int stop_ptraced_child(int pid, void *stack, int exitcode, - int mustexit) -{ - int status, n, ret = 0; - - if(ptrace(PTRACE_CONT, pid, 0, 0) < 0) - fatal_perror("stop_ptraced_child : ptrace failed"); - CATCH_EINTR(n = waitpid(pid, &status, 0)); - if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) { - int exit_with = WEXITSTATUS(status); - if (exit_with == 2) - non_fatal("check_ptrace : child exited with status 2. " - "\nDisabling SYSEMU support.\n"); - non_fatal("check_ptrace : child exited with exitcode %d, while " - "expecting %d; status 0x%x\n", exit_with, - exitcode, status); - if (mustexit) - exit(1); - ret = -1; - } - - if(munmap(stack, UM_KERN_PAGE_SIZE) < 0) - fatal_perror("check_ptrace : munmap failed"); - return ret; -} - /* Changed only during early boot */ int ptrace_faultinfo = 1; int ptrace_ldt = 1; @@ -207,131 +101,23 @@ __uml_setup("nosysemu", nosysemu_cmd_par static void __init check_sysemu(void) { - void *stack; - unsigned long regs[MAX_REG_NR]; - int pid, n, status, count=0; - non_fatal("Checking syscall emulation patch for ptrace..."); - sysemu_supported = 0; - pid = start_ptraced_child(&stack); - - if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0) - goto fail; - - CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); - if (n < 0) - fatal_perror("check_sysemu : wait failed"); - if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) - fatal("check_sysemu : expected SIGTRAP, got status = %d", - status); - - if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) - fatal_perror("check_sysemu : PTRACE_GETREGS failed"); - if(PT_SYSCALL_NR(regs) != __NR_getpid){ - non_fatal("check_sysemu got system call number %d, " - "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid); - goto fail; - } - - n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, os_getpid()); - if(n < 0){ - non_fatal("check_sysemu : failed to modify system call " - "return"); - goto fail; - } - - if (stop_ptraced_child(pid, stack, 0, 0) < 0) - goto fail_stopped; - sysemu_supported = 1; non_fatal("OK\n"); set_using_sysemu(!force_sysemu_disabled); non_fatal("Checking advanced syscall emulation patch for ptrace..."); - pid = start_ptraced_child(&stack); - - if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0, - (void *) PTRACE_O_TRACESYSGOOD) < 0)) - fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed"); - - while(1){ - count++; - if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0) - goto fail; - CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); - if(n < 0) - fatal_perror("check_ptrace : wait failed"); - - if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP|0x80))){ - if (!count) - fatal("check_ptrace : SYSEMU_SINGLESTEP " - "doesn't singlestep"); - n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, - os_getpid()); - if(n < 0) - fatal_perror("check_sysemu : failed to modify " - "system call return"); - break; - } - else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP)) - count++; - else - fatal("check_ptrace : expected SIGTRAP or " - "(SIGTRAP | 0x80), got status = %d", status); - } - if (stop_ptraced_child(pid, stack, 0, 0) < 0) - goto fail_stopped; - sysemu_supported = 2; non_fatal("OK\n"); if ( !force_sysemu_disabled ) set_using_sysemu(sysemu_supported); return; - -fail: - stop_ptraced_child(pid, stack, 1, 0); -fail_stopped: - non_fatal("missing\n"); } static void __init check_ptrace(void) { - void *stack; - int pid, syscall, n, status; - non_fatal("Checking that ptrace can change system call numbers..."); - pid = start_ptraced_child(&stack); - - if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0, - (void *) PTRACE_O_TRACESYSGOOD) < 0)) - fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed"); - - while(1){ - if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0) - fatal_perror("check_ptrace : ptrace failed"); - - CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); - if(n < 0) - fatal_perror("check_ptrace : wait failed"); - - if(!WIFSTOPPED(status) || - (WSTOPSIG(status) != (SIGTRAP | 0x80))) - fatal("check_ptrace : expected (SIGTRAP|0x80), " - "got status = %d", status); - - syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET, - 0); - if(syscall == __NR_getpid){ - n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, - __NR_getppid); - if(n < 0) - fatal_perror("check_ptrace : failed to modify " - "system call"); - break; - } - } - stop_ptraced_child(pid, stack, 0, 1); non_fatal("OK\n"); check_sysemu(); } @@ -411,63 +197,15 @@ __uml_setup("noptraceldt", noptraceldt_c #ifdef UML_CONFIG_MODE_SKAS static inline void check_skas3_ptrace_faultinfo(void) { - struct ptrace_faultinfo fi; - void *stack; - int pid, n; - non_fatal(" - PTRACE_FAULTINFO..."); - pid = start_ptraced_child(&stack); - - n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi); - if (n < 0) { - ptrace_faultinfo = 0; - if(errno == EIO) - non_fatal("not found\n"); - else - perror("not found"); - } - else { - if (!ptrace_faultinfo) - non_fatal("found but disabled on command line\n"); - else - non_fatal("found\n"); - } - - init_registers(pid); - stop_ptraced_child(pid, stack, 1, 1); + non_fatal("not found\n"); } static inline void check_skas3_ptrace_ldt(void) { #ifdef PTRACE_LDT - void *stack; - int pid, n; - unsigned char ldtbuf[40]; - struct ptrace_ldt ldt_op = (struct ptrace_ldt) { - .func = 2, /* read default ldt */ - .ptr = ldtbuf, - .bytecount = sizeof(ldtbuf)}; - non_fatal(" - PTRACE_LDT..."); - pid = start_ptraced_child(&stack); - - n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op); - if (n < 0) { - if(errno == EIO) - non_fatal("not found\n"); - else { - perror("not found"); - } - ptrace_ldt = 0; - } - else { - if(ptrace_ldt) - non_fatal("found\n"); - else - non_fatal("found, but use is disabled\n"); - } - - stop_ptraced_child(pid, stack, 1, 1); + non_fatal("not found\n"); #else /* PTRACE_LDT might be disabled via cmdline option. * We want to override this, else we might use the stub - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
