On Mon, Feb 18, 2013 at 10:22:20PM +0100, Julien Cristau wrote: > On Sat, Feb 16, 2013 at 16:45:54 +0100, Marcin Slusarz wrote: > > > Libunwind generates backtraces much more reliably than glibc's "backtrace". > > > mind adding an example in the commit message (before/after)? Sure.
--- From: Marcin Slusarz <[email protected]> Subject: [PATCH] os: use libunwind to generate backtraces Libunwind generates backtraces much more reliably than glibc "backtrace". Before: 0: /opt/xserver/bin/X (0x400000+0x18ce36) [0x58ce36] 1: /opt/xserver/bin/X (xorg_backtrace+0x9) [0x58d119] 2: /opt/xserver/bin/X (0x400000+0x190d69) [0x590d69] 3: /lib64/libpthread.so.0 (0x7fb904268000+0x10a90) [0x7fb904278a90] 4: /lib64/libc.so.6 (ioctl+0x7) [0x7fb902fbf987] 5: /usr/lib64/libdrm.so.2 (drmIoctl+0x28) [0x7fb90405ffa8] 6: /usr/lib64/libdrm.so.2 (drmCommandWrite+0x1b) [0x7fb90406235b] 7: /usr/lib64/libdrm_nouveau.so.2 (nouveau_bo_wait+0x89) [0x7fb902009719] 8: /opt/xserver/lib/xorg/modules/drivers/nouveau_drv.so (0x7fb90220e000+0x76f3) [0x7fb9022156f3] 9: /opt/xserver/lib/xorg/modules/libexa.so (0x7fb9019c7000+0xbae0) [0x7fb9019d2ae0] 10: /opt/xserver/bin/X (0x400000+0x17d2b3) [0x57d2b3] 11: /opt/xserver/bin/X (0x400000+0xc9930) [0x4c9930] 12: /opt/xserver/bin/X (0x400000+0x3a81a) [0x43a81a] 13: /opt/xserver/bin/X (0x400000+0x3d6a1) [0x43d6a1] 14: /opt/xserver/bin/X (0x400000+0x2c2ca) [0x42c2ca] 15: /lib64/libc.so.6 (__libc_start_main+0xf5) [0x7fb902f019b5] 16: /opt/xserver/bin/X (0x400000+0x2c60d) [0x42c60d] 17: ?? [0x0] After: 0: /opt/xserver/bin/X (OsSigHandler+0x39) [0x590d69] 1: /lib64/libpthread.so.0 (__restore_rt+0x0) [0x7fb904278a8f] 2: /lib64/libc.so.6 (ioctl+0x7) [0x7fb902fbf987] 3: /usr/lib64/libdrm.so.2 (drmIoctl+0x28) [0x7fb90405ffa8] 4: /usr/lib64/libdrm.so.2 (drmCommandWrite+0x1b) [0x7fb90406235b] 5: /usr/lib64/libdrm_nouveau.so.2 (nouveau_bo_wait+0x89) [0x7fb902009719] 6: /opt/xserver/lib/xorg/modules/drivers/nouveau_drv.so (nouveau_exa_download_from_screen+0x1a3) [0x7fb9022156f3] 7: /opt/xserver/lib/xorg/modules/libexa.so (exaGetImage+0x1f0) [0x7fb9019d2ae0] 8: /opt/xserver/bin/X (miSpriteGetImage+0x173) [0x57d2b3] 9: /opt/xserver/bin/X (compGetImage+0xb0) [0x4c9930] 10: /opt/xserver/bin/X (ProcGetImage+0x55a) [0x43a81a] 11: /opt/xserver/bin/X (Dispatch+0x341) [0x43d6a1] 12: /opt/xserver/bin/X (main+0x3ba) [0x42c2ca] 13: /lib64/libc.so.6 (__libc_start_main+0xf5) [0x7fb902f019b5] 14: /opt/xserver/bin/X (_start+0x29) [0x42c60d] 15: ? (?+0x29) [0x29] Signed-off-by: Marcin Slusarz <[email protected]> --- configure.ac | 7 +++++ include/dix-config.h.in | 3 +++ os/Makefile.am | 5 ++++ os/backtrace.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 85 insertions(+) diff --git a/configure.ac b/configure.ac index 9415a54..4a292da 100644 --- a/configure.ac +++ b/configure.ac @@ -309,6 +309,13 @@ AC_CHECK_HEADER([execinfo.h],[ ])] ) +PKG_CHECK_MODULES(LIBUNWIND, libunwind, [HAVE_LIBUNWIND=yes], [HAVE_LIBUNWIND=no]) +if test "x$HAVE_LIBUNWIND" = xyes; then + AC_DEFINE(HAVE_LIBUNWIND, 1, [Have libunwind support]) +fi +AM_CONDITIONAL(HAVE_LIBUNWIND, [test "x$HAVE_LIBUNWIND" = xyes]) + + dnl --------------------------------------------------------------------------- dnl Bus options and CPU capabilities. Replaces logic in dnl hw/xfree86/os-support/bus/Makefile.am, among others. diff --git a/include/dix-config.h.in b/include/dix-config.h.in index 578f249..5102263 100644 --- a/include/dix-config.h.in +++ b/include/dix-config.h.in @@ -60,6 +60,9 @@ /* Has backtrace support */ #undef HAVE_BACKTRACE +/* Has libunwind support */ +#undef HAVE_LIBUNWIND + /* Define to 1 if you have the <byteswap.h> header file. */ #undef HAVE_BYTESWAP_H diff --git a/os/Makefile.am b/os/Makefile.am index 8891485..364b6da 100644 --- a/os/Makefile.am +++ b/os/Makefile.am @@ -34,6 +34,11 @@ if XDMCP libos_la_SOURCES += $(XDMCP_SRCS) endif +if HAVE_LIBUNWIND +AM_CFLAGS += $(LIBUNWIND_CFLAGS) +libos_la_LIBADD += $(LIBUNWIND_LIBS) +endif + EXTRA_DIST = $(SECURERPC_SRCS) $(XDMCP_SRCS) if SPECIAL_DTRACE_OBJECTS diff --git a/os/backtrace.c b/os/backtrace.c index daac60c..02aeb03 100644 --- a/os/backtrace.c +++ b/os/backtrace.c @@ -30,6 +30,75 @@ #include <errno.h> #include <string.h> +#ifdef HAVE_LIBUNWIND + +#define UNW_LOCAL_ONLY +#include <libunwind.h> + +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif +#include <dlfcn.h> + +void +xorg_backtrace(void) +{ + unw_cursor_t cursor; + unw_context_t context; + unw_word_t off; + unw_proc_info_t pip; + int ret, i = 0; + char procname[256]; + const char *filename; + Dl_info dlinfo; + + pip.unwind_info = NULL; + ret = unw_getcontext(&context); + if (ret) { + ErrorFSigSafe("unw_getcontext: %d\n", ret); + return; + } + + ret = unw_init_local(&cursor, &context); + if (ret) { + ErrorFSigSafe("unw_init_local: %d\n", ret); + return; + } + + ErrorFSigSafe("\n"); + ErrorFSigSafe("Backtrace:\n"); + ret = unw_step(&cursor); + while (ret > 0) { + ret = unw_get_proc_info(&cursor, &pip); + if (ret) { + ErrorFSigSafe("unw_get_proc_info: %d\n", ret); + break; + } + + ret = unw_get_proc_name(&cursor, procname, 256, &off); + if (ret && ret != -UNW_ENOMEM) { + if (ret != -UNW_EUNSPEC) + ErrorFSigSafe("unw_get_proc_name: %d\n", ret); + procname[0] = '?'; + procname[1] = 0; + } + + if (dladdr((void *)(pip.start_ip + off), &dlinfo) && dlinfo.dli_fname && + *dlinfo.dli_fname) + filename = dlinfo.dli_fname; + else + filename = "?"; + + ErrorFSigSafe("%u: %s (%s%s+0x%x) [%p]\n", i++, filename, procname, + ret == -UNW_ENOMEM ? "..." : "", (int)off, (void *)(pip.start_ip + off)); + + ret = unw_step(&cursor); + if (ret < 0) + ErrorFSigSafe("unw_step: %d\n", ret); + } + ErrorFSigSafe("\n"); +} +#else #ifdef HAVE_BACKTRACE #ifndef _GNU_SOURCE #define _GNU_SOURCE @@ -246,3 +315,4 @@ xorg_backtrace(void) #endif #endif +#endif -- 1.8.1 _______________________________________________ [email protected]: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel
