From: Tatjana Azundris Nuernberg
Date: December 13 2012 2:42pm
Subject: bzr push into mysql-trunk branch (tatjana.nuernberg:5239 to 5240)
 Bug#14475946
List-Archive: http://lists.mysql.com/commits/145516
X-Bug: 14475946
Message-Id: <20121213144243.19626.80284.5240@envy>
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 5240 Tatjana Azundris Nuernberg	2012-12-13
      Bug#14475946: Cannot retrieve MySQL 5.0 stacktrace on Linux
      
      In 5.5+, we use the backtrace() interface on linux
      which was added to glibc in 2.1, circa 1999.
      (At the time of this patch, we officially support glibc
      2.3 and up.)
      
      This package removes our homebrew solution, which is
      now essentially dead code, and prints a message to the
      DBA if they somehow manage to reach it anyway.
      
      (Mind that this would presumably necessitate linking
      against a stone age glibc, or a libc that is not GNU.
      Either way, we fail gracefully in such cases.)
     @ mysys/stacktrace.c
        Remove dead code that handled linux without backtrace(),
        which wth glibc shouldn't happen since 2.1 as of ca. 1999.
        Our "supported platforms" lists glibc 2.3 as a minimum,
        and even alphalinux and debian for alpha ran much longer
        than that. Besides, we fail gracefully in such setups and
        inform the user (at would-be backtrace time) about what's
        going on.

    modified:
      mysys/stacktrace.c
 5239 Dmitry Lenev	2012-12-13 [merge]
      Merged follow-up for the fix for bug #15954872 "MAKE MDL
      SUBSYSTEM AND TABLE DEFINITION CACHE ROBUST AGAINST BUGS
      IN CALLERS" in mysql-trunk.

    modified:
      unittest/gunit/mdl-t.cc
=== modified file 'mysys/stacktrace.c'
--- a/mysys/stacktrace.c	2012-11-22 14:40:47 +0000
+++ b/mysys/stacktrace.c	2012-12-13 14:40:36 +0000
@@ -241,91 +241,12 @@ void my_print_stacktrace(uchar* stack_bo
 
 #elif defined(TARGET_OS_LINUX)
 
-#ifdef __i386__
-#define SIGRETURN_FRAME_OFFSET 17
-#endif
-
-#ifdef __x86_64__
-#define SIGRETURN_FRAME_OFFSET 23
-#endif
-
-void my_print_stacktrace(uchar* stack_bottom, ulong thread_stack)
+void my_print_stacktrace(uchar* stack_bottom __attribute__((unused)),
+                         ulong thread_stack __attribute__((unused)))
 {
-  uchar** fp;
-  uint frame_count = 0, sigreturn_frame_count;
-  LINT_INIT(fp);
-
-
-#ifdef __i386__
-  __asm __volatile__ ("movl %%ebp,%0"
-		      :"=r"(fp)
-		      :"r"(fp));
-#endif
-#ifdef __x86_64__
-  __asm __volatile__ ("movq %%rbp,%0"
-		      :"=r"(fp)
-		      :"r"(fp));
-#endif
-  if (!fp)
-  {
-    my_safe_printf_stderr("%s",
-      "frame pointer is NULL, did you compile with\n"
-      "-fomit-frame-pointer? Aborting backtrace!\n");
-    return;
-  }
-
-  if (!stack_bottom || (uchar*) stack_bottom > (uchar*) &fp)
-  {
-    ulong tmp= MY_MIN(0x10000, thread_stack);
-    /* Assume that the stack starts at the previous even 65K */
-    stack_bottom= (uchar*) (((ulong) &fp + tmp) & ~(ulong) 0xFFFF);
-    my_safe_printf_stderr("Cannot determine thread, fp=%p, "
-                          "backtrace may not be correct.\n", fp);
-  }
-  if (fp > (uchar**) stack_bottom ||
-      fp < (uchar**) stack_bottom - thread_stack)
-  {
-    my_safe_printf_stderr("Bogus stack limit or frame pointer, "
-                          "fp=%p, stack_bottom=%p, thread_stack=%ld, "
-                          "aborting backtrace.\n",
-                          fp, stack_bottom, thread_stack);
-    return;
-  }
-
-  my_safe_printf_stderr("%s",
-    "Stack range sanity check OK, backtrace follows:\n");
-
-  /* We are 1 frame above signal frame with NPTL and 2 frames above with LT */
-  sigreturn_frame_count = thd_lib_detected == THD_LIB_LT ? 2 : 1;
-
-  while (fp < (uchar**) stack_bottom)
-  {
-#if defined(__i386__) || defined(__x86_64__)
-    uchar** new_fp = (uchar**)*fp;
-    my_safe_printf_stderr("%p\n",
-                          frame_count == sigreturn_frame_count ?
-                          *(fp + SIGRETURN_FRAME_OFFSET) : *(fp + 1));
-#endif /* defined(__386__)  || defined(__x86_64__) */
-
-    if (new_fp <= fp )
-    {
-      my_safe_printf_stderr("New value of fp=%p failed sanity check, "
-                            "terminating stack trace!\n", new_fp);
-      goto end;
-    }
-    fp = new_fp;
-    ++frame_count;
-  }
-  my_safe_printf_stderr("%s",
-                        "Stack trace seems successful - bottom reached\n");
-
-end:
   my_safe_printf_stderr("%s",
-    "Please read "
-    "http://dev.mysql.com/doc/refman/5.1/en/resolve-stack-dump.html\n"
-    "and follow instructions on how to resolve the stack trace.\n"
-    "Resolved stack trace is much more helpful in diagnosing the\n"
-    "problem, so please do resolve it\n");
+    "\nFunction backtrace() not found in glibc though it should \n"
+    "be available from version 2.1 on ... Omitting stacktrace.\n\n");
 }
 #endif /* TARGET_OS_LINUX */
 #endif /* HAVE_STACKTRACE */

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