09636efd1b
Bail out of test_dump_stack() if the stack trace is empty rather than invoking addr2line with zero addresses. The problem with the latter is that addr2line will block waiting for addresses to be passed in via stdin, e.g. if running a selftest from an interactive terminal. Opportunistically fix up the comment that mentions skipping 3 frames since only 2 are skipped in the code. Cc: Vipin Sharma <vipinsh@google.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: David Matlack <dmatlack@google.com> Message-Id: <20220922231724.3560211-1-dmatlack@google.com> [Small tweak to keep backtrace() call close to if(). - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* tools/testing/selftests/kvm/lib/assert.c
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*
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* Copyright (C) 2018, Google LLC.
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*/
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#define _GNU_SOURCE /* for getline(3) and strchrnul(3)*/
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#include "test_util.h"
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#include <execinfo.h>
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#include <sys/syscall.h>
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#include "kselftest.h"
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/* Dumps the current stack trace to stderr. */
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static void __attribute__((noinline)) test_dump_stack(void);
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static void test_dump_stack(void)
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{
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/*
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* Build and run this command:
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*
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* addr2line -s -e /proc/$PPID/exe -fpai {backtrace addresses} | \
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* cat -n 1>&2
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*
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* Note that the spacing is different and there's no newline.
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*/
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size_t i;
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size_t n = 20;
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void *stack[n];
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const char *addr2line = "addr2line -s -e /proc/$PPID/exe -fpai";
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const char *pipeline = "|cat -n 1>&2";
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char cmd[strlen(addr2line) + strlen(pipeline) +
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/* N bytes per addr * 2 digits per byte + 1 space per addr: */
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n * (((sizeof(void *)) * 2) + 1) +
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/* Null terminator: */
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1];
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char *c = cmd;
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n = backtrace(stack, n);
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/*
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* Skip the first 2 frames, which should be test_dump_stack() and
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* test_assert(); both of which are declared noinline. Bail if the
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* resulting stack trace would be empty. Otherwise, addr2line will block
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* waiting for addresses to be passed in via stdin.
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*/
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if (n <= 2) {
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fputs(" (stack trace empty)\n", stderr);
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return;
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}
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c += sprintf(c, "%s", addr2line);
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for (i = 2; i < n; i++)
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c += sprintf(c, " %lx", ((unsigned long) stack[i]) - 1);
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c += sprintf(c, "%s", pipeline);
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wunused-result"
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system(cmd);
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#pragma GCC diagnostic pop
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}
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static pid_t _gettid(void)
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{
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return syscall(SYS_gettid);
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}
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void __attribute__((noinline))
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test_assert(bool exp, const char *exp_str,
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const char *file, unsigned int line, const char *fmt, ...)
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{
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va_list ap;
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if (!(exp)) {
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va_start(ap, fmt);
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fprintf(stderr, "==== Test Assertion Failure ====\n"
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" %s:%u: %s\n"
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" pid=%d tid=%d errno=%d - %s\n",
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file, line, exp_str, getpid(), _gettid(),
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errno, strerror(errno));
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test_dump_stack();
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if (fmt) {
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fputs(" ", stderr);
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vfprintf(stderr, fmt, ap);
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fputs("\n", stderr);
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}
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va_end(ap);
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if (errno == EACCES) {
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print_skip("Access denied - Exiting");
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exit(KSFT_SKIP);
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}
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exit(254);
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}
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return;
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}
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