c77bed81a2
Daniel Stenberg
2025-11-24
Subject
memdebug: produce stack trace dump with libbacktrace
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Commit Diff GitHub →
configure.ac+16 -0
| @@ -1108,6 +1108,22 @@ AS_HELP_STRING([--enable-libgcc],[use libgcc when linking]), | |
| AC_MSG_RESULT(no) | |
| ) | |
| + | AC_MSG_CHECKING([whether to use libbacktrace]) |
| + | AC_ARG_WITH(backtrace, |
| + | AS_HELP_STRING([--enable-backtrace],[use libbacktrace when linking]), |
| + | [ case "$enableval" in |
| + | yes) |
| + | LIBS="-lbacktrace $LIBS" |
| + | AC_DEFINE(USE_BACKTRACE, 1, [if libbacktrace is in use]) |
| + | AC_MSG_RESULT(yes) |
| + | ;; |
| + | *) |
| + | AC_MSG_RESULT(no) |
| + | ;; |
| + | esac ], |
| + | AC_MSG_RESULT(no) |
| + | ) |
| + | |
| CURL_CHECK_LIB_XNET | |
| dnl gethostbyname without lib or in the nsl lib? | |
lib/memdebug.c+38 -0
| @@ -31,6 +31,10 @@ | |
| #include "urldata.h" | |
| #include "curlx/fopen.h" /* for CURLX_FOPEN_LOW(), CURLX_FREOPEN_LOW() */ | |
| + | #ifdef USE_BACKTRACE |
| + | #include "backtrace.h" |
| + | #endif |
| + | |
| /* The last 2 #include files should be in this order */ | |
| #include "curl_memory.h" | |
| #include "memdebug.h" | |
| @@ -58,6 +62,9 @@ FILE *curl_dbg_logfile = NULL; | |
| static bool registered_cleanup = FALSE; /* atexit registered cleanup */ | |
| static bool memlimit = FALSE; /* enable memory limit */ | |
| static long memsize = 0; /* set number of mallocs allowed */ | |
| + | #ifdef USE_BACKTRACE |
| + | struct backtrace_state *btstate; |
| + | #endif |
| /* LeakSantizier (LSAN) calls _exit() instead of exit() when a leak is detected | |
| on exit so the logfile must be closed explicitly or data could be lost. | |
| @@ -73,6 +80,33 @@ static void curl_dbg_cleanup(void) | |
| } | |
| curl_dbg_logfile = NULL; | |
| } | |
| + | #ifdef USE_BACKTRACE |
| + | static void error_callback(void *data, const char *message, int error_number) |
| + | { |
| + | (void)data; |
| + | if(error_number == -1) |
| + | curl_dbg_log("compile with -g\n\n"); |
| + | else |
| + | curl_dbg_log("Backtrace error %d: %s\n", error_number, message); |
| + | } |
| + | |
| + | static int full_callback(void *data, uintptr_t pc, const char *pathname, |
| + | int line_number, const char *function) |
| + | { |
| + | (void)data; |
| + | (void)pc; |
| + | if(pathname || function || line_number) |
| + | curl_dbg_log("BT %s:%d -- %s\n", pathname, line_number, function); |
| + | return 0; |
| + | } |
| + | |
| + | static void dump_bt(void) |
| + | { |
| + | backtrace_full(btstate, 0, full_callback, error_callback, NULL); |
| + | } |
| + | #else |
| + | #define dump_bt() /* nothing to do */ |
| + | #endif |
| /* this sets the log filename */ | |
| void curl_dbg_memdebug(const char *logname) | |
| @@ -88,6 +122,9 @@ void curl_dbg_memdebug(const char *logname) | |
| setbuf(curl_dbg_logfile, (char *)NULL); | |
| #endif | |
| } | |
| + | #ifdef USE_BACKTRACE |
| + | btstate = backtrace_create_state(NULL, 0, error_callback, NULL); |
| + | #endif |
| if(!registered_cleanup) | |
| registered_cleanup = !atexit(curl_dbg_cleanup); | |
| } | |
| @@ -115,6 +152,7 @@ static bool countcheck(const char *func, int line, const char *source) | |
| /* log to stderr also */ | |
| curl_mfprintf(stderr, "LIMIT %s:%d %s reached memlimit\n", | |
| source, line, func); | |
| + | dump_bt(); |
| fflush(curl_dbg_logfile); /* because it might crash now */ | |
| /* !checksrc! disable ERRNOVAR 1 */ | |
| errno = ENOMEM; | |
tests/memanalyze.pl+4 -1
| @@ -130,7 +130,10 @@ while(<$fileh>) { | |
| chomp $_; | |
| my $line = $_; | |
| $lnum++; | |
| - | if($line =~ /^LIMIT ([^ ]*):(\d*) (.*)/) { |
| + | if($line =~ /^BT/) { |
| + | # back-trace, ignore |
| + | } |
| + | elsif($line =~ /^LIMIT ([^ ]*):(\d*) (.*)/) { |
| # new memory limit test prefix | |
| my $i = $3; | |
| my ($source, $linenum) = ($1, $2); | |