diff options
| -rw-r--r-- | ChangeLog | 20 | ||||
| -rw-r--r-- | malloc/Makefile | 1 | ||||
| -rw-r--r-- | malloc/tst-mallocfork2.c | 137 |
3 files changed, 106 insertions, 52 deletions
@@ -1,3 +1,23 @@ +2019-05-08 Florian Weimer <fweimer@redhat.com> + + malloc/tst-mallocfork2: Use process-shared barriers. + * malloc/tst-mallocfork2.c: Switch to <support/test-driver.c>. + (signal_count, sigusr1_sender_pid): Remove. + (iterations): Define constant. + (shared): New variable. + (sigusr1_received): Update comment. + (sigusr1_handler): Do not send SIGSTOP to the sender process. + (signal_sender): Optional use barriers to avoid sending signals + during irrelevant times. + (do_it): Initialize variable shared. Use xfork for error + checking. Launch multiple SIGUSR1-sending subprocesses. Limit + the iteration count, independent of signal delivery. Check for + deadlocks in fork. Introduce barriers for reducing signal + traffic. Do not send SIGCONT to the SIGUSR1-sending processes; + replaced by the barriers. Count signals during fork/free/malloc + and report them. + * malloc/Makefile (tst-mallocfork): Link with libpthread. + 2019-05-07 Joseph Myers <joseph@codesourcery.com> * sysdeps/unix/sysv/linux/syscall-names.list: Update kernel diff --git a/malloc/Makefile b/malloc/Makefile index aadf602dfd..d2fba29953 100644 --- a/malloc/Makefile +++ b/malloc/Makefile @@ -252,3 +252,4 @@ $(objpfx)tst-dynarray-fail-mem.out: $(objpfx)tst-dynarray-fail.out $(objpfx)tst-malloc-tcache-leak: $(shared-thread-library) $(objpfx)tst-malloc_info: $(shared-thread-library) +$(objpfx)tst-mallocfork2: $(shared-thread-library) diff --git a/malloc/tst-mallocfork2.c b/malloc/tst-mallocfork2.c index 474b0cea4a..30e7abe6fd 100644 --- a/malloc/tst-mallocfork2.c +++ b/malloc/tst-mallocfork2.c @@ -34,6 +34,11 @@ #include <sys/wait.h> #include <time.h> #include <unistd.h> +#include <array_length.h> +#include <support/check.h> +#include <support/support.h> +#include <support/xthread.h> +#include <support/xunistd.h> /* How many malloc objects to keep arond. */ enum { malloc_objects = 1009 }; @@ -41,19 +46,16 @@ enum { malloc_objects = 1009 }; /* The maximum size of an object. */ enum { malloc_maximum_size = 70000 }; -/* How many signals need to be delivered before the test exits. */ -enum { signal_count = 1000 }; +/* How many iterations the test performs before exiting. */ +enum { iterations = 10000 }; -static int do_test (void); -#define TIMEOUT 100 -#define TEST_FUNCTION do_test () -#include "../test-skeleton.c" - -/* Process ID of the subprocess which sends SIGUSR1 signals. */ -static pid_t sigusr1_sender_pid; +/* Barrier for synchronization with the processes sending SIGUSR1 + signals, to make it more likely that the signals arrive during a + fork/free/malloc call. */ +static struct { pthread_barrier_t barrier; } *shared; /* Set to 1 if SIGUSR1 is received. Used to detect a signal during - malloc/free. */ + fork/free/malloc. */ static volatile sig_atomic_t sigusr1_received; /* Periodically set to 1, to indicate that the process is making @@ -63,17 +65,6 @@ static volatile sig_atomic_t progress_indicator = 1; static void sigusr1_handler (int signo) { - /* Let the main program make progress, by temporarily suspending - signals from the subprocess. */ - if (sigusr1_received) - return; - /* sigusr1_sender_pid might not be initialized in the parent when - the first SIGUSR1 signal arrives. */ - if (sigusr1_sender_pid > 0 && kill (sigusr1_sender_pid, SIGSTOP) != 0) - { - write_message ("error: kill (SIGSTOP)\n"); - abort (); - } sigusr1_received = 1; /* Perform a fork with a trivial subprocess. */ @@ -108,6 +99,8 @@ liveness_signal_handler (int signo) write_message ("warning: process seems to be stuck\n"); } +/* Send SIGNO to the parent process. If SLEEP, wait a second between + signals, otherwise use barriers to delay sending signals. */ static void __attribute__ ((noreturn)) signal_sender (int signo, bool sleep) @@ -115,6 +108,8 @@ signal_sender (int signo, bool sleep) pid_t target = getppid (); while (true) { + if (!sleep) + xpthread_barrier_wait (&shared->barrier); if (kill (target, signo) != 0) { dprintf (STDOUT_FILENO, "error: kill: %m\n"); @@ -123,14 +118,17 @@ signal_sender (int signo, bool sleep) if (sleep) usleep (1 * 1000 * 1000); else - /* Reduce the rate at which we send signals. */ - sched_yield (); + xpthread_barrier_wait (&shared->barrier); } } static int do_test (void) { + /* shared->barrier is intialized along with sigusr1_sender_pids + below. */ + shared = support_shared_allocate (sizeof (*shared)); + struct sigaction action = { .sa_handler = sigusr1_handler, @@ -150,48 +148,74 @@ do_test (void) return 1; } - pid_t sigusr2_sender_pid = fork (); + pid_t sigusr2_sender_pid = xfork (); if (sigusr2_sender_pid == 0) signal_sender (SIGUSR2, true); - sigusr1_sender_pid = fork (); - if (sigusr1_sender_pid == 0) - signal_sender (SIGUSR1, false); + + /* Send SIGUSR1 signals from several processes. Hopefully, one + signal will hit one of the ciritical functions. Use a barrier to + avoid sending signals while not running fork/free/malloc. */ + pid_t sigusr1_sender_pids[5]; + { + pthread_barrierattr_t attr; + xpthread_barrierattr_init (&attr); + xpthread_barrierattr_setpshared (&attr, PTHREAD_PROCESS_SHARED); + xpthread_barrier_init (&shared->barrier, &attr, + array_length (sigusr1_sender_pids) + 1); + xpthread_barrierattr_destroy (&attr); + } + for (size_t i = 0; i < array_length (sigusr1_sender_pids); ++i) + { + sigusr1_sender_pids[i] = fork (); + if (sigusr1_sender_pids[i] == 0) + signal_sender (SIGUSR1, false); + } void *objects[malloc_objects] = {}; - unsigned signals = 0; + unsigned int fork_signals = 0; + unsigned int free_signals = 0; + unsigned int malloc_signals = 0; unsigned seed = 1; - time_t last_report = 0; - while (signals < signal_count) + for (int i = 0; i < iterations; ++i) { progress_indicator = 1; int slot = rand_r (&seed) % malloc_objects; size_t size = rand_r (&seed) % malloc_maximum_size; - if (kill (sigusr1_sender_pid, SIGCONT) != 0) + + /* Occasionally do a fork first, to catch deadlocks there as + well (see bug 24161). */ + bool do_fork = (rand_r (&seed) % 7) == 0; + + xpthread_barrier_wait (&shared->barrier); + if (do_fork) { - printf ("error: kill (SIGCONT): %m\n"); - signal (SIGUSR1, SIG_IGN); - kill (sigusr1_sender_pid, SIGKILL); - kill (sigusr2_sender_pid, SIGKILL); - return 1; + sigusr1_received = 0; + pid_t pid = xfork (); + if (sigusr1_received) + ++fork_signals; + if (pid == 0) + _exit (0); + int status; + int ret = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)); + if (ret < 0) + FAIL_EXIT1 ("waitpid: %m"); + TEST_COMPARE (status, 0); } - sigusr1_received = false; + sigusr1_received = 0; free (objects[slot]); + if (sigusr1_received) + ++free_signals; + sigusr1_received = 0; objects[slot] = malloc (size); if (sigusr1_received) - { - ++signals; - time_t current = time (0); - if (current != last_report) - { - printf ("info: SIGUSR1 signal count: %u\n", signals); - last_report = current; - } - } + ++malloc_signals; + xpthread_barrier_wait (&shared->barrier); + if (objects[slot] == NULL) { printf ("error: malloc: %m\n"); - signal (SIGUSR1, SIG_IGN); - kill (sigusr1_sender_pid, SIGKILL); + for (size_t i = 0; i < array_length (sigusr1_sender_pids); ++i) + kill (sigusr1_sender_pids[i], SIGKILL); kill (sigusr2_sender_pid, SIGKILL); return 1; } @@ -201,11 +225,20 @@ do_test (void) for (int slot = 0; slot < malloc_objects; ++slot) free (objects[slot]); - /* Terminate the signal-sending subprocess. The SIGUSR1 handler - should no longer run because it uses sigusr1_sender_pid. */ - signal (SIGUSR1, SIG_IGN); - kill (sigusr1_sender_pid, SIGKILL); + for (size_t i = 0; i < array_length (sigusr1_sender_pids); ++i) + kill (sigusr1_sender_pids[i], SIGKILL); kill (sigusr2_sender_pid, SIGKILL); + printf ("info: signals received during fork: %u\n", fork_signals); + printf ("info: signals received during free: %u\n", free_signals); + printf ("info: signals received during malloc: %u\n", malloc_signals); + + /* Do not destroy the barrier because of the SIGKILL above, which + may have left the barrier in an inconsistent state. */ + support_shared_free (shared); + return 0; } + +#define TIMEOUT 100 +#include <support/test-driver.c> |