From 8eefbac3b67756f0dfe9d68741d70015023b5216 Mon Sep 17 00:00:00 2001
From: Martin Milata <mmilata@redhat.com>
Date: Fri, 17 Jul 2015 12:52:49 +0200
Subject: [PATCH] Create core backtrace in unwind hook
Related to #829.
We need to implement #882 in order for this to work. This change
requires (yet unreleased) satyr-0.16.
The feature is turned off by default, you need to pass
--enable-dump-time-unwind to configure in order to enable it.
Signed-off-by: Martin Milata <mmilata@redhat.com>
Conflicts:
src/hooks/abrt-hook-ccpp.c
---
configure.ac | 12 ++++
doc/abrt-CCpp.conf.txt | 18 ++++++
src/hooks/CCpp.conf | 15 +++++
src/hooks/abrt-hook-ccpp.c | 108 ++++++++++++++++++++++++------------
src/hooks/abrt-install-ccpp-hook.in | 4 +-
5 files changed, 121 insertions(+), 36 deletions(-)
diff --git a/configure.ac b/configure.ac
index 56b8ad8..330dd9c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -232,6 +232,18 @@ AC_ARG_ENABLE([native-unwinder],
[fi]
+# Perform stack unwind on live/dying process in the core handler?
+
+AC_ARG_ENABLE([dump-time-unwind],
+ AS_HELP_STRING([--enable-dump-time-unwind],
+ [create core stack trace while the crashed process is still in memory (default is no)]),
+ [], [enable_dump_time_unwind=no])
+
+[if test "$enable_native_unwinder" = "yes" -a "$enable_dump_time_unwind" = "yes"]
+[then]
+ AC_DEFINE([ENABLE_DUMP_TIME_UNWIND], [1], [Create core stacktrace while the process is still in memory.])
+[fi]
+
AC_SUBST(CONF_DIR)
AC_SUBST(DEFAULT_CONF_DIR)
AC_SUBST(VAR_RUN)
diff --git a/doc/abrt-CCpp.conf.txt b/doc/abrt-CCpp.conf.txt
index ad3830b..498d53d 100644
--- a/doc/abrt-CCpp.conf.txt
+++ b/doc/abrt-CCpp.conf.txt
@@ -19,12 +19,30 @@ SaveBinaryImage = 'yes' / 'no' ...::
Useful, for example, when _deleted binary_ segfaults.
Default is 'no'.
+CreateCoreBacktrace = 'yes' / 'no' ...::
+ When this option is set to 'yes', core backtrace is generated
+ from the memory image of the crashing process. Only the crash
+ thread is present in the backtrace. This feature requires
+ kernel 3.18 or newer, otherwise the core backtrace is not
+ created.
+ Default is 'yes'.
+
+SaveFullCore = 'yes' / 'no' ...::
+ Save full coredump? If set to 'no', coredump won't be saved
+ and you won't be able to report the crash to Bugzilla. Only
+ useful with 'CreateCoreBacktrace' set to 'yes'. Please
+ note that if this option is set to 'no' and MakeCompatCore
+ is set to 'yes', the core is still written to the current
+ directory.
+ Default is 'yes'.
+
VerboseLog = NUM::
Used to make the hook more verbose
SEE ALSO
--------
abrt.conf(5)
+abrt-action-generate-core-backtrace(1)
AUTHORS
-------
diff --git a/src/hooks/CCpp.conf b/src/hooks/CCpp.conf
index d199116..b1a0a22 100644
--- a/src/hooks/CCpp.conf
+++ b/src/hooks/CCpp.conf
@@ -8,6 +8,21 @@ MakeCompatCore = yes
# (useful, for example, when _deleted binary_ segfaults)
SaveBinaryImage = no
+# When this option is set to 'yes', core backtrace is generated
+# from the memory image of the crashing process. Only the crash
+# thread is present in the backtrace. This feature requires
+# kernel 3.18 or newer, otherwise the core backtrace is not
+# created.
+CreateCoreBacktrace = yes
+
+# Save full coredump? If set to 'no', coredump won't be saved
+# and you won't be able to report the crash to Bugzilla. Only
+# useful with CreateCoreBacktrace set to 'yes'. Please
+# note that if this option is set to 'no' and MakeCompatCore
+# is set to 'yes', the core is still written to the current
+# directory.
+SaveFullCore = yes
+
# Used for debugging the hook
#VerboseLog = 2
diff --git a/src/hooks/abrt-hook-ccpp.c b/src/hooks/abrt-hook-ccpp.c
index 2dd9ac6..b5f00f6 100644
--- a/src/hooks/abrt-hook-ccpp.c
+++ b/src/hooks/abrt-hook-ccpp.c
@@ -22,6 +22,11 @@
#include "libabrt.h"
#include <selinux/selinux.h>
+#ifdef ENABLE_DUMP_TIME_UNWIND
+#include <satyr/abrt.h>
+#include <satyr/utils.h>
+#endif /* ENABLE_DUMP_TIME_UNWIND */
+
#define DUMP_SUID_UNSAFE 1
#define DUMP_SUID_SAFE 2
@@ -155,13 +160,13 @@ static struct dump_dir *dd;
* %g - gid
* %t - UNIX time of dump
* %e - executable filename
- * %h - hostname
+ * %i - crash thread tid
* %% - output one "%"
*/
/* Hook must be installed with exactly the same sequence of %c specifiers.
* Last one, %h, may be omitted (we can find it out).
*/
-static const char percent_specifiers[] = "%scpugteh";
+static const char percent_specifiers[] = "%scpugtei";
static char *core_basename = (char*) "core";
static char* get_executable(pid_t pid, int *fd_p)
@@ -580,6 +585,24 @@ static int create_or_die(const char *filename, int user_core_fd)
perror_msg_and_die("Can't open '%s'", filename);
}
+static void create_core_backtrace(pid_t tid, const char *executable, int signal_no, const char *dd_path)
+{
+#ifdef ENABLE_DUMP_TIME_UNWIND
+ if (g_verbose > 1)
+ sr_debug_parser = true;
+
+ char *error_message = NULL;
+ bool success = sr_abrt_create_core_stacktrace_from_core_hook(dd_path, tid, executable,
+ signal_no, &error_message);
+
+ if (!success)
+ {
+ log("Failed to create core_backtrace: %s", error_message);
+ free(error_message);
+ }
+#endif /* ENABLE_DUMP_TIME_UNWIND */
+}
+
static int create_user_core(int user_core_fd, pid_t pid, off_t ulimit_c)
{
int err = 1;
@@ -619,9 +642,9 @@ int main(int argc, char** argv)
if (argc < 8)
{
- /* percent specifier: %s %c %p %u %g %t %e %h */
+ /* percent specifier: %s %c %p %u %g %t %e %i */
/* argv: [0] [1] [2] [3] [4] [5] [6] [7] [8]*/
- error_msg_and_die("Usage: %s SIGNO CORE_SIZE_LIMIT PID UID GID TIME BINARY_NAME [HOSTNAME]", argv[0]);
+ error_msg_and_die("Usage: %s SIGNO CORE_SIZE_LIMIT PID UID GID TIME BINARY_NAME [TID]", argv[0]);
}
/* Not needed on 2.6.30.
@@ -646,6 +669,8 @@ int main(int argc, char** argv)
/* ... and plugins/CCpp.conf */
bool setting_MakeCompatCore;
bool setting_SaveBinaryImage;
+ bool setting_SaveFullCore;
+ bool setting_CreateCoreBacktrace;
{
map_string_t *settings = new_map_string();
load_abrt_plugin_conf_file("CCpp.conf", settings);
@@ -654,6 +679,10 @@ int main(int argc, char** argv)
setting_MakeCompatCore = value && string_to_bool(value);
value = get_map_string_item_or_NULL(settings, "SaveBinaryImage");
setting_SaveBinaryImage = value && string_to_bool(value);
+ value = get_map_string_item_or_NULL(settings, "SaveFullCore");
+ setting_SaveFullCore = value ? string_to_bool(value) : true;
+ value = get_map_string_item_or_NULL(settings, "CreateCoreBacktrace");
+ setting_CreateCoreBacktrace = value ? string_to_bool(value) : true;
value = get_map_string_item_or_NULL(settings, "VerboseLog");
if (value)
g_verbose = xatoi_positive(value);
@@ -686,11 +715,10 @@ int main(int argc, char** argv)
free(s);
}
- struct utsname uts;
- if (!argv[8]) /* no HOSTNAME? */
+ pid_t tid = 0;
+ if (argv[8])
{
- uname(&uts);
- argv[8] = uts.nodename;
+ tid = xatoi_positive(argv[8]);
}
char path[PATH_MAX];
@@ -906,36 +934,42 @@ int main(int argc, char** argv)
off_t sz = copyfd_eof(src_fd_binary, dst_fd, COPYFD_SPARSE);
if (fsync(dst_fd) != 0 || close(dst_fd) != 0 || sz < 0)
{
- dd_delete(dd);
- error_msg_and_die("Error saving '%s'", path);
+ dd_delete(dd); error_msg_and_die("Error saving '%s'", path);
}
close(src_fd_binary);
}
- strcpy(path + path_len, "/"FILENAME_COREDUMP);
- int abrt_core_fd = create_or_die(path, user_core_fd);
-
- /* We write both coredumps at once.
- * We can't write user coredump first, since it might be truncated
- * and thus can't be copied and used as abrt coredump;
- * and if we write abrt coredump first and then copy it as user one,
- * then we have a race when process exits but coredump does not exist yet:
- * $ echo -e '#include<signal.h>\nmain(){raise(SIGSEGV);}' | gcc -o test -x c -
- * $ rm -f core*; ulimit -c unlimited; ./test; ls -l core*
- * 21631 Segmentation fault (core dumped) ./test
- * ls: cannot access core*: No such file or directory <=== BAD
- */
- off_t core_size = copyfd_sparse(STDIN_FILENO, abrt_core_fd, user_core_fd, ulimit_c);
-
- close_user_core(user_core_fd, core_size);
-
- if (fsync(abrt_core_fd) != 0 || close(abrt_core_fd) != 0 || core_size < 0)
+ off_t core_size = 0;
+ if (setting_SaveFullCore)
{
- unlink(path);
- dd_delete(dd);
- /* copyfd_sparse logs the error including errno string,
- * but it does not log file name */
- error_msg_and_die("Error writing '%s'", path);
+ strcpy(path + path_len, "/"FILENAME_COREDUMP);
+ int abrt_core_fd = create_or_die(path, user_core_fd);
+
+ /* We write both coredumps at once.
+ * We can't write user coredump first, since it might be truncated
+ * and thus can't be copied and used as abrt coredump;
+ * and if we write abrt coredump first and then copy it as user one,
+ * then we have a race when process exits but coredump does not exist yet:
+ * $ echo -e '#include<signal.h>\nmain(){raise(SIGSEGV);}' | gcc -o test -x c -
+ * $ rm -f core*; ulimit -c unlimited; ./test; ls -l core*
+ * 21631 Segmentation fault (core dumped) ./test
+ * ls: cannot access core*: No such file or directory <=== BAD
+ */
+ core_size = copyfd_sparse(STDIN_FILENO, abrt_core_fd, user_core_fd, ulimit_c);
+ close_user_core(user_core_fd, core_size);
+ if (fsync(abrt_core_fd) != 0 || close(abrt_core_fd) != 0 || core_size < 0)
+ {
+ unlink(path);
+ dd_delete(dd);
+ /* copyfd_sparse logs the error including errno string,
+ * but it does not log file name */
+ error_msg_and_die("Error writing '%s'", path);
+ }
+ }
+ else
+ {
+ /* User core is created even if WriteFullCore is off. */
+ create_user_core(user_core_fd, pid, ulimit_c);
}
/* Because of #1211835 and #1126850 */
@@ -977,6 +1011,10 @@ int main(int argc, char** argv)
/* And finally set the right uid and gid */
dd_reset_ownership(dd);
+ /* Perform crash-time unwind of the guilty thread. */
+ if (tid > 0 && setting_CreateCoreBacktrace)
+ create_core_backtrace(tid, executable, signal_no, dd->dd_dirname);
+
/* We close dumpdir before we start catering for crash storm case.
* Otherwise, delete_dump_dir's from other concurrent
* CCpp's won't be able to delete our dump (their delete_dump_dir
@@ -990,7 +1028,9 @@ int main(int argc, char** argv)
strcpy(path, newpath);
free(newpath);
- log("Saved core dump of pid %lu (%s) to %s (%llu bytes)", (long)pid, executable, path, (long long)core_size);
+ if (core_size > 0)
+ log_notice("Saved core dump of pid %lu (%s) to %s (%llu bytes)",
+ (long)pid, executable, path, (long long)core_size);
notify_new_path(path);
diff --git a/src/hooks/abrt-install-ccpp-hook.in b/src/hooks/abrt-install-ccpp-hook.in
index aa01231..d4ed4a5 100755
--- a/src/hooks/abrt-install-ccpp-hook.in
+++ b/src/hooks/abrt-install-ccpp-hook.in
@@ -11,9 +11,9 @@ SAVED_PATTERN_DIR="@VAR_RUN@/abrt"
SAVED_PATTERN_FILE="@VAR_RUN@/abrt/saved_core_pattern"
HOOK_BIN="@libexecdir@/abrt-hook-ccpp"
# Must match percent_specifiers[] order in abrt-hook-ccpp.c:
-PATTERN="|$HOOK_BIN %s %c %p %u %g %t %e"
+PATTERN="|$HOOK_BIN %s %c %p %u %g %t %e %i"
# Same, but with bogus "executable name" parameter
-PATTERN1="|$HOOK_BIN %s %c %p %u %g %t e"
+PATTERN1="|$HOOK_BIN %s %c %p %u %g %t e %i"
# core_pipe_limit specifies how many dump_helpers can run at the same time
# 0 - means unlimited, but it's not guaranteed that /proc/<pid> of crashing
--
2.4.3