| https://gitlab.com/samba-team/samba/-/commit/14feb93d481011765f62614ab49b304e17e4f6fd |
| https://gitlab.com/samba-team/samba/-/merge_requests/2401?commit_id=ac8064cb0d79db377df75a22a240632dbc37f99f |
| https://bugs.gentoo.org/791349 |
| |
| From 14feb93d481011765f62614ab49b304e17e4f6fd Mon Sep 17 00:00:00 2001 |
| From: Andrew Bartlett <abartlet@samba.org> |
| Date: Tue, 7 Jun 2022 15:07:59 +1200 |
| Subject: [PATCH] lib/util: Prefer backtrace_symbols() for internal backtraces |
| |
| Backtraces when Samba is in PANIC state are better with |
| backtrace_symbols() than with libunwind on Ubuntu 20.04 x86_64 |
| so move libunwind to a off-by-default option, prompted for |
| if backtrace_symbols() is not available. |
| |
| Based on a request by Fco Javier Felix <ffelix@inode64.com> |
| |
| Signed-off-by: Andrew Bartlett <abartlet@samba.org> |
| Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz> |
| --- a/lib/util/fault.c |
| +++ b/lib/util/fault.c |
| @@ -222,9 +222,13 @@ _PUBLIC_ void smb_panic(const char *why) |
| void log_stack_trace(void) |
| { |
| #ifdef HAVE_LIBUNWIND |
| - /* Try to use libunwind before any other technique since on ia64 |
| - * libunwind correctly walks the stack in more circumstances than |
| - * backtrace. |
| + /* |
| + * --with-libunwind is required to use libunwind, the |
| + * backtrace_symbols() code below is the default. |
| + * |
| + * This code is available because a previous version of this |
| + * comment asserted that on ia64 libunwind correctly walks the |
| + * stack in more circumstances than backtrace. |
| */ |
| unw_cursor_t cursor; |
| unw_context_t uc; |
| --- a/lib/util/wscript |
| +++ b/lib/util/wscript |
| @@ -2,6 +2,15 @@ def options(opt): |
| ''' This is a bit strange, but disable is the flag, not enable. ''' |
| opt.add_option('--disable-fault-handling', action='store_true', dest='disable_fault_handling', help=('disable the fault handlers'), default=False) |
| |
| + # We do not want libunwind by default (backtrace_symbols() in |
| + # glibc is better) but allow (eg) IA-64 to build with it where it |
| + # might be better (per old comment in fault.c) |
| + opt.samba_add_onoff_option('libunwind', |
| + default=None, |
| + help='''Use libunwind instead of the default backtrace_symbols() |
| + from libc, for example on IA-64 where it might give a better |
| + backtrace.''') |
| + |
| opt.add_option('--with-systemd', |
| help=("Enable systemd integration"), |
| action='store_true', dest='enable_systemd') |
| --- a/lib/util/wscript_configure |
| +++ b/lib/util/wscript_configure |
| @@ -1,23 +1,35 @@ |
| #!/usr/bin/env python |
| -from waflib import Logs, Options |
| +from waflib import Logs, Options, Errors |
| |
| import os, sys |
| |
| if Options.options.disable_fault_handling: |
| conf.DEFINE('HAVE_DISABLE_FAULT_HANDLING',1) |
| |
| -# backtrace could be in libexecinfo or in libc |
| +# backtrace could be in libexecinfo or in libc. |
| +# This is our preferred backtrace handler (more useful output than libunwind as at Ubuntu 20.04 x86_64) |
| conf.CHECK_FUNCS_IN('backtrace backtrace_symbols', 'execinfo', checklibc=True, headers='execinfo.h') |
| conf.CHECK_HEADERS('execinfo.h') |
| |
| conf.SET_TARGET_TYPE('LIBUNWIND', 'EMPTY') |
| -if conf.check_cfg(package='libunwind-generic', |
| - args='--cflags --libs', |
| - msg='Checking for libunwind', |
| - uselib_store='LIBUNWIND', |
| - mandatory=False): |
| - if conf.CHECK_HEADERS('libunwind.h'): |
| - conf.SET_TARGET_TYPE('LIBUNWIND', 'SYSLIB') |
| +if Options.options.with_libunwind: |
| + if conf.check_cfg(package='libunwind-generic', |
| + args='--cflags --libs', |
| + msg='Checking for libunwind', |
| + uselib_store='LIBUNWIND', |
| + mandatory=False): |
| + if conf.CHECK_HEADERS('libunwind.h'): |
| + conf.SET_TARGET_TYPE('LIBUNWIND', 'SYSLIB') |
| + else: |
| + raise Errors.WafError('--with-libunwind specified but libunwind not found') |
| +elif Options.options.with_libunwind == None: |
| + if not conf.CONFIG_SET('HAVE_BACKTRACE_SYMBOLS') \ |
| + and not Options.options.disable_fault_handling: |
| + raise Errors.WafError( |
| +'''backtrace_symbols() not found but |
| +--with-libunwind not specified. |
| +Use --without-libunwind to build without internal backtrace support or |
| +--disable-fault-handling to totally defer fault handling to the OS.''') |
| |
| conf.CHECK_STRUCTURE_MEMBER('struct statvfs', 'f_frsize', define='HAVE_FRSIZE', headers='sys/statvfs.h') |
| |
| --- a/script/autobuild.py |
| +++ b/script/autobuild.py |
| @@ -480,10 +480,11 @@ tasks = { |
| # MIT Kerberos from the current system. Runtime behaviour is |
| # confirmed via the ktest (static ccache and keytab) environment |
| |
| + # This environment also used to confirm we can still build with --with-libunwind |
| "samba-ktest-mit": { |
| "sequence": [ |
| ("random-sleep", random_sleep(300, 900)), |
| - ("configure", "./configure.developer --without-ad-dc --with-system-mitkrb5 " + samba_configure_params), |
| + ("configure", "./configure.developer --without-ad-dc --with-libunwind --with-system-mitkrb5 " + samba_configure_params), |
| ("make", "make -j"), |
| ("test", make_test(include_envs=[ |
| "ktest", # ktest is also tested in fileserver, samba and |
| GitLab |
