From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1506 invoked by alias); 27 Jul 2010 20:55:23 -0000 Received: (qmail 1488 invoked by uid 22791); 27 Jul 2010 20:55:17 -0000 X-SWARE-Spam-Status: No, hits=-5.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,TW_TP,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 27 Jul 2010 20:55:07 +0000 Received: from int-mx04.intmail.prod.int.phx2.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.17]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o6RKsvbd017125 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 27 Jul 2010 16:54:57 -0400 Received: from host1.dyn.jankratochvil.net (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx04.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o6RKss69000891 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 27 Jul 2010 16:54:56 -0400 Received: from host1.dyn.jankratochvil.net (localhost [127.0.0.1]) by host1.dyn.jankratochvil.net (8.14.4/8.14.4) with ESMTP id o6RKssWS000612; Tue, 27 Jul 2010 22:54:54 +0200 Received: (from jkratoch@localhost) by host1.dyn.jankratochvil.net (8.14.4/8.14.4/Submit) id o6RKsqsm000608; Tue, 27 Jul 2010 22:54:52 +0200 Date: Tue, 27 Jul 2010 20:55:00 -0000 From: Jan Kratochvil To: Pedro Alves Cc: gdb-patches@sourceware.org Subject: Re: [patch] Fix linux-ia64 on SIGILL for deleted breakpoint Message-ID: <20100727205452.GA22833@host1.dyn.jankratochvil.net> References: <20100719085817.GA24395@host1.dyn.jankratochvil.net> <201007242326.05269.pedro@codesourcery.com> <20100725185217.GA24476@host1.dyn.jankratochvil.net> <201007271243.16407.pedro@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201007271243.16407.pedro@codesourcery.com> User-Agent: Mutt/1.5.20 (2009-12-10) X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2010-07/txt/msg00446.txt.bz2 On Tue, 27 Jul 2010 13:43:16 +0200, Pedro Alves wrote: > On Sunday 25 July 2010 19:52:17, Jan Kratochvil wrote: > > On Sun, 25 Jul 2010 00:26:04 +0200, Pedro Alves wrote: > If your check on s390 is good, than that might have broken (rare ...) corner > cases on s390, like a SIGILL reported for an instruction set at the address > consecutive to an inserted software breakpoint. gdb/gdbserver/linux-low.c maybe_internal_trap may get set wrong on s390, OK. > > Which arch uses gdbarch_decr_pc_after_break && generates a non-SIGTRAP signal > > on a GDB-placed breakpoint? It is probably none of the arches I target (i686, > > x86_64, ppc{,64}, s390{,x}, ia64, possibly arm). > > I don't have a list. Some archs may generate that only on some > situations (or used to and no longer do on more up to date versions). kernel > > > (Alternatively, recode to avoid the assumption) > > > > Sorry I do not try to code anything without an iron to test it. > > What I meant was to have your new code not depend on decr_pc_after > break being 0, you don't need any other system to try that on. > It meant, to not have any code path in the SIGILL > case that calls gdbarch_decr_pc_after_break at all. Conceptually, > something like: > > if (sig == SIGTRAP && software_breakpoint_inserted_at (PC - decr_pc_after_breakpoint)) > { > rewind pc, discard signal > return 1 > } > else if (sig == SIGILL && software_breakpoint_inserted_at (PC)) > { > discard signal > return 1 > } > return 0 I believe we could need some ` - decr_pc_after_sigill' in the second conditional as shown on the s390 case. But only if GDB would place any such SIGILL instruction so this paragraph is just a hand waving. Not implementing this alternative way, thanks for the analysis. > Okay. Please fix the spelling of "alternative". I am sorry. Checked-in. Thanks, Jan http://sourceware.org/ml/gdb-cvs/2010-07/msg00170.html --- src/gdb/ChangeLog 2010/07/27 20:44:30 1.12025 +++ src/gdb/ChangeLog 2010/07/27 20:51:37 1.12026 @@ -1,3 +1,14 @@ +2010-07-27 Jan Kratochvil + + * ia64-linux-nat.c (ia64_linux_status_is_event): New function. + (_initialize_ia64_linux_nat): Install it. + * linux-nat.c (sigtrap_is_event, linux_nat_status_is_event) + (linux_nat_set_status_is_event): New. + (stop_wait_callback, count_events_callback, select_event_lwp_callback) + cancel_breakpoints_callback, linux_nat_filter_event) + (linux_nat_wait_1): Use linux_nat_status_is_event. + * linux-nat.h (linux_nat_set_status_is_event): New prototype. + 2010-07-27 Tom Tromey * NEWS: Mention labels, .gdb_index. --- src/gdb/ia64-linux-nat.c 2010/07/07 16:15:16 1.49 +++ src/gdb/ia64-linux-nat.c 2010/07/27 20:51:37 1.50 @@ -809,6 +809,18 @@ offset, len); } +/* For break.b instruction ia64 CPU forgets the immediate value and generates + SIGILL with ILL_ILLOPC instead of more common SIGTRAP with TRAP_BRKPT. + ia64 does not use gdbarch_decr_pc_after_break so we do not have to make any + difference for the signals here. */ + +static int +ia64_linux_status_is_event (int status) +{ + return WIFSTOPPED (status) && (WSTOPSIG (status) == SIGTRAP + || WSTOPSIG (status) == SIGILL); +} + void _initialize_ia64_linux_nat (void); void @@ -848,4 +860,5 @@ /* Register the target. */ linux_nat_add_target (t); linux_nat_set_new_thread (t, ia64_linux_new_thread); + linux_nat_set_status_is_event (t, ia64_linux_status_is_event); } --- src/gdb/linux-nat.c 2010/07/25 09:31:12 1.178 +++ src/gdb/linux-nat.c 2010/07/27 20:51:37 1.179 @@ -2605,6 +2605,29 @@ return lp->stopped_data_address_p; } +/* Commonly any breakpoint / watchpoint generate only SIGTRAP. */ + +static int +sigtrap_is_event (int status) +{ + return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP; +} + +/* SIGTRAP-like events recognizer. */ + +static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event; + +/* Set alternative SIGTRAP-like events recognizer. If + breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be + applied. */ + +void +linux_nat_set_status_is_event (struct target_ops *t, + int (*status_is_event) (int status)) +{ + linux_nat_status_is_event = status_is_event; +} + /* Wait until LP is stopped. */ static int @@ -2645,7 +2668,7 @@ if (WSTOPSIG (status) != SIGSTOP) { - if (WSTOPSIG (status) == SIGTRAP) + if (linux_nat_status_is_event (status)) { /* If a LWP other than the LWP that we're reporting an event for has hit a GDB breakpoint (as opposed to @@ -2801,7 +2824,7 @@ /* Count only resumed LWPs that have a SIGTRAP event pending. */ if (lp->status != 0 && lp->resumed - && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) + && linux_nat_status_is_event (lp->status)) (*count)++; return 0; @@ -2829,7 +2852,7 @@ /* Select only resumed LWPs that have a SIGTRAP event pending. */ if (lp->status != 0 && lp->resumed - && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) + && linux_nat_status_is_event (lp->status)) if ((*selector)-- == 0) return 1; @@ -2891,7 +2914,7 @@ if (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE && lp->status != 0 - && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP + && linux_nat_status_is_event (lp->status) && cancel_breakpoint (lp)) /* Throw away the SIGTRAP. */ lp->status = 0; @@ -3064,7 +3087,7 @@ return NULL; } - if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP) + if (linux_nat_status_is_event (status)) { /* Save the trap's siginfo in case we need it later. */ save_siginfo (lp); @@ -3411,7 +3434,7 @@ threads. */ if (non_stop && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE - && WSTOPSIG (lp->status) == SIGTRAP + && linux_nat_status_is_event (lp->status) && cancel_breakpoint (lp)) { /* Throw away the SIGTRAP. */ @@ -3627,7 +3650,7 @@ else lp->resumed = 0; - if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP) + if (linux_nat_status_is_event (status)) { if (debug_linux_nat) fprintf_unfiltered (gdb_stdlog, --- src/gdb/linux-nat.h 2010/06/11 12:10:12 1.35 +++ src/gdb/linux-nat.h 2010/07/27 20:51:37 1.36 @@ -172,3 +172,7 @@ /* Compute and return the processor core of a given thread. */ int linux_nat_core_of_thread_1 (ptid_t ptid); + +/* Set alternative SIGTRAP-like events recognizer. */ +void linux_nat_set_status_is_event (struct target_ops *t, + int (*status_is_event) (int status)); --- src/gdb/testsuite/ChangeLog 2010/07/27 18:08:47 1.2391 +++ src/gdb/testsuite/ChangeLog 2010/07/27 20:51:37 1.2392 @@ -1,3 +1,8 @@ +2010-07-27 Jan Kratochvil + + * gdb.threads/ia64-sigill.exp: New file. + * gdb.threads/ia64-sigill.c: New file. + 2010-07-27 Tom Tromey * gdb.opt/inline-cmds.c (ATTR): New define. --- src/gdb/testsuite/gdb.threads/ia64-sigill.c +++ src/gdb/testsuite/gdb.threads/ia64-sigill.c 2010-07-27 20:51:55.245809000 +0000 @@ -0,0 +1,360 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2010 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define gettid() syscall (__NR_gettid) + +/* Terminate always in the main task, it can lock up with SIGSTOPped GDB + otherwise. */ +#define TIMEOUT (gettid () == getpid() ? 10 : 15) + +static pid_t thread1_tid; +static pthread_cond_t thread1_tid_cond = PTHREAD_COND_INITIALIZER; +static pthread_mutex_t thread1_tid_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; + +static pid_t thread2_tid; +static pthread_cond_t thread2_tid_cond = PTHREAD_COND_INITIALIZER; +static pthread_mutex_t thread2_tid_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; + +static pthread_mutex_t terminate_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; + +/* Do not use alarm as it would create a ptrace event which would hang up us if + we are being traced by GDB which we stopped ourselves. */ + +static void timed_mutex_lock (pthread_mutex_t *mutex) +{ + int i; + struct timespec start, now; + + i = clock_gettime (CLOCK_MONOTONIC, &start); + assert (i == 0); + + do + { + i = pthread_mutex_trylock (mutex); + if (i == 0) + return; + assert (i == EBUSY); + + i = clock_gettime (CLOCK_MONOTONIC, &now); + assert (i == 0); + assert (now.tv_sec >= start.tv_sec); + } + while (now.tv_sec - start.tv_sec < TIMEOUT); + + fprintf (stderr, "Timed out waiting for internal lock!\n"); + exit (EXIT_FAILURE); +} + +static void * +thread_func (void *threadno_voidp) +{ + int threadno = (intptr_t) threadno_voidp; + int i; + + switch (threadno) + { + case 1: + timed_mutex_lock (&thread1_tid_mutex); + + /* THREAD1_TID_MUTEX must be already locked to avoid race. */ + thread1_tid = gettid (); + + i = pthread_cond_signal (&thread1_tid_cond); + assert (i == 0); + i = pthread_mutex_unlock (&thread1_tid_mutex); + assert (i == 0); + + break; + + case 2: + timed_mutex_lock (&thread2_tid_mutex); + + /* THREAD2_TID_MUTEX must be already locked to avoid race. */ + thread2_tid = gettid (); + + i = pthread_cond_signal (&thread2_tid_cond); + assert (i == 0); + i = pthread_mutex_unlock (&thread2_tid_mutex); + assert (i == 0); + + break; + + default: + assert (0); + } + +#ifdef __ia64__ + asm volatile ("label:\n" + "nop.m 0\n" + "nop.i 0\n" + "nop.b 0\n"); +#endif + /* break-here */ + + /* Be sure the "t (tracing stop)" test can proceed for both threads. */ + timed_mutex_lock (&terminate_mutex); + i = pthread_mutex_unlock (&terminate_mutex); + assert (i == 0); + + return NULL; +} + +static const char * +proc_string (const char *filename, const char *line) +{ + FILE *f; + static char buf[LINE_MAX]; + size_t line_len = strlen (line); + + f = fopen (filename, "r"); + if (f == NULL) + { + fprintf (stderr, "fopen (\"%s\") for \"%s\": %s\n", filename, line, + strerror (errno)); + exit (EXIT_FAILURE); + } + while (errno = 0, fgets (buf, sizeof (buf), f)) + { + char *s; + + s = strchr (buf, '\n'); + assert (s != NULL); + *s = 0; + + if (strncmp (buf, line, line_len) != 0) + continue; + + if (fclose (f)) + { + fprintf (stderr, "fclose (\"%s\") for \"%s\": %s\n", filename, line, + strerror (errno)); + exit (EXIT_FAILURE); + } + + return &buf[line_len]; + } + if (errno != 0) + { + fprintf (stderr, "fgets (\"%s\": %s\n", filename, strerror (errno)); + exit (EXIT_FAILURE); + } + fprintf (stderr, "\"%s\": No line \"%s\" found.\n", filename, line); + exit (EXIT_FAILURE); +} + +static unsigned long +proc_ulong (const char *filename, const char *line) +{ + const char *s = proc_string (filename, line); + long retval; + char *end; + + errno = 0; + retval = strtol (s, &end, 10); + if (retval < 0 || retval >= LONG_MAX || (end && *end)) + { + fprintf (stderr, "\"%s\":\"%s\": %ld, %s\n", filename, line, retval, + strerror (errno)); + exit (EXIT_FAILURE); + } + return retval; +} + +static void +state_wait (pid_t process, const char *wanted) +{ + char *filename; + int i; + struct timespec start, now; + const char *state; + + i = asprintf (&filename, "/proc/%lu/status", (unsigned long) process); + assert (i > 0); + + i = clock_gettime (CLOCK_MONOTONIC, &start); + assert (i == 0); + + do + { + state = proc_string (filename, "State:\t"); + + /* torvalds/linux-2.6.git 464763cf1c6df632dccc8f2f4c7e50163154a2c0 + has changed "T (tracing stop)" to "t (tracing stop)". Make the GDB + testcase backward compatible with older Linux kernels. */ + if (strcmp (state, "T (tracing stop)") == 0) + state = "t (tracing stop)"; + + if (strcmp (state, wanted) == 0) + { + free (filename); + return; + } + + if (sched_yield ()) + { + perror ("sched_yield()"); + exit (EXIT_FAILURE); + } + + i = clock_gettime (CLOCK_MONOTONIC, &now); + assert (i == 0); + assert (now.tv_sec >= start.tv_sec); + } + while (now.tv_sec - start.tv_sec < TIMEOUT); + + fprintf (stderr, "Timed out waiting for PID %lu \"%s\" (now it is \"%s\")!\n", + (unsigned long) process, wanted, state); + exit (EXIT_FAILURE); +} + +static volatile pid_t tracer = 0; +static pthread_t thread1, thread2; + +static void +cleanup (void) +{ + printf ("Resuming GDB PID %lu.\n", (unsigned long) tracer); + + if (tracer) + { + int i; + int tracer_save = tracer; + + tracer = 0; + + i = kill (tracer_save, SIGCONT); + assert (i == 0); + } +} + +int +main (int argc, char **argv) +{ + int i; + int standalone = 0; + + if (argc == 2 && strcmp (argv[1], "-s") == 0) + standalone = 1; + else + assert (argc == 1); + + setbuf (stdout, NULL); + + timed_mutex_lock (&thread1_tid_mutex); + timed_mutex_lock (&thread2_tid_mutex); + + timed_mutex_lock (&terminate_mutex); + + i = pthread_create (&thread1, NULL, thread_func, (void *) (intptr_t) 1); + assert (i == 0); + + i = pthread_create (&thread2, NULL, thread_func, (void *) (intptr_t) 2); + assert (i == 0); + + if (!standalone) + { + tracer = proc_ulong ("/proc/self/status", "TracerPid:\t"); + if (tracer == 0) + { + fprintf (stderr, "The testcase must be run by GDB!\n"); + exit (EXIT_FAILURE); + } + if (tracer != getppid ()) + { + fprintf (stderr, "The testcase parent must be our GDB tracer!\n"); + exit (EXIT_FAILURE); + } + } + + /* SIGCONT our debugger in the case of our crash as we would deadlock + otherwise. */ + + atexit (cleanup); + + printf ("Stopping GDB PID %lu.\n", (unsigned long) tracer); + + if (tracer) + { + i = kill (tracer, SIGSTOP); + assert (i == 0); + state_wait (tracer, "T (stopped)"); + } + + /* Threads are now waiting at timed_mutex_lock (thread1_tid_mutex) and so + they could not trigger the breakpoint before GDB gets unstopped later. + Threads get resumed at pthread_cond_wait below. Use `while' loops for + protection against spurious pthread_cond_wait wakeups. */ + + printf ("Waiting till the threads initialize their TIDs.\n"); + + while (thread1_tid == 0) + { + i = pthread_cond_wait (&thread1_tid_cond, &thread1_tid_mutex); + assert (i == 0); + } + + while (thread2_tid == 0) + { + i = pthread_cond_wait (&thread2_tid_cond, &thread2_tid_mutex); + assert (i == 0); + } + + printf ("Thread 1 TID = %lu, thread 2 TID = %lu, PID = %lu.\n", + (unsigned long) thread1_tid, (unsigned long) thread2_tid, + (unsigned long) getpid ()); + + printf ("Waiting till the threads get trapped by the breakpoint.\n"); + + if (tracer) + { + /* s390x-unknown-linux-gnu will fail with "R (running)". */ + + state_wait (thread1_tid, "t (tracing stop)"); + + state_wait (thread2_tid, "t (tracing stop)"); + } + + cleanup (); + + printf ("Joining the threads.\n"); + + i = pthread_mutex_unlock (&terminate_mutex); + assert (i == 0); + + i = pthread_join (thread1, NULL); + assert (i == 0); + + i = pthread_join (thread2, NULL); + assert (i == 0); + + printf ("Exiting.\n"); /* break-at-exit */ + + return EXIT_SUCCESS; +} --- src/gdb/testsuite/gdb.threads/ia64-sigill.exp +++ src/gdb/testsuite/gdb.threads/ia64-sigill.exp 2010-07-27 20:51:55.778901000 +0000 @@ -0,0 +1,76 @@ +# This testcase is part of GDB, the GNU debugger. + +# Copyright 2010 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# Test SIGILL generated by some special cases of breakpoints on ia64. Problem +# was SIGILL being stored in non-current thread for later retrieval when its +# breakpoint has been already deleted. moribund locations are not active in +# the default all-stop mode. + +set testfile "ia64-sigill" +set srcfile ${testfile}.c +set binfile ${objdir}/${subdir}/${testfile} +if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" ${binfile} executable [list debug additional_flags=-lrt]] != "" } { + return -1 +} + +clean_restart $testfile + +if ![runto_main] { + return -1 +} + +set test "info addr label" +gdb_test_multiple $test $test { + -re "Symbol \"label\" is at 0x\[0-9a-f\]+0 in .*\r\n$gdb_prompt $" { + # Verify the label really starts at the start of ia64 bundle. + pass $test + + # ia64 generates SIGILL for breakpoint at B slot of an MIB bundle. + gdb_test "break *label+2" {Breakpoint [0-9]+ at 0x[0-9a-f]+2:.*} + } + -re "No symbol \"label\" in current context\\.\r\n$gdb_prompt $" { + pass $test + + # Either this target never generates non-SIGTRAP signals or they do + # not depend on the breakpoint address. Try any address. + gdb_breakpoint [gdb_get_line_number "break-here"] + } +} + +gdb_test_no_output {set $sigill_bpnum=$bpnum} + +gdb_breakpoint [gdb_get_line_number "break-at-exit"] + +gdb_test_no_output "set debug infrun 1" + +# The ia64 SIGILL signal is visible only in the lin-lwp debug. +gdb_test_no_output "set debug lin-lwp 1" + +gdb_test "continue" "Breakpoint \[0-9\]+,( .* in)? thread_func .*" + +gdb_test_no_output {delete $sigill_bpnum} + +set test "continue for the pending signal" +gdb_test_multiple "continue" $test { + -re "Breakpoint \[0-9\]+, .*break-at-exit.*\r\n$gdb_prompt $" { + # Breakpoint has been skipped in the other thread. + pass $test + } + -re "Program received signal .*\r\n$gdb_prompt $" { + fail $test + } +}