From: Philippe Waroquiers <philippe.waroquiers@skynet.be>
Date: Wed, 7 Sep 2016 20:12:30 +0000 (+0000)
Subject: Fix 199468 - Suppressions: stack size limited to 25 while --num-callers allows more... 
X-Git-Tag: svn/VALGRIND_3_12_0~78
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5de4bad5a75e701412f001923d403876ee6165de;p=thirdparty%2Fvalgrind.git

Fix 199468 - Suppressions: stack size limited to 25 while --num-callers allows more frames

Nr of callers in a suppression entry had a smaller limit than the max
for --num-callers.
This means it was not possible to precisely suppress an error with a big
stack trace.
Also, --gen-suppressions was not providing the full stack trace of
the error in the generated suppressions.

Now, a suppression entry can have the same nr of callers as a backtrace.
Generated suppressions are generated with up to --num-callers callers.

This change has neglectible impact :
* memory: stack array of 500*2 words is declared, instead of 24*2 words
  This array is declared on the interim stack (startup stack), which is
  largely big enough.
* cpu : neglectible more cpu needed to read suppression entries
        (to initialise the bigger stack array when reading a supp entry),
Apart of the above, no impact on performance (unless of course bigger
supp entries are really used).

Note that this does not impact the behaviour for existing suppression files.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15945
---

diff --git a/NEWS b/NEWS
index ebc1968b70..75ef71646e 100644
--- a/NEWS
+++ b/NEWS
@@ -26,6 +26,11 @@ n-i-bz Improved thread startup time significantly on non-Linux platforms.
   "nouserintercepts" can be any non-existing library name).
   This new functionality is not implemented for darwin/macosx.
 
+* The maximum number of callers in a suppression entry is now equal to
+  the maximum size for --num-callers (500).
+  Note that --gen-suppressions=yes|all similarly generate suppression
+  containing up to --num-callers frames.
+
 * New and modified GDB server monitor features:
 
   - Valgrind's gdbserver now accepts the command 'catch syscall'.
@@ -58,6 +63,7 @@ To see details of a given bug, visit
 where XXXXXX is the bug number as listed below.
 
 191069  Exiting due to signal not reported in XML output
+199468  Suppressions: stack size limited to 25 while --num-callers allows more frames
 212352  vex amd64 unhandled opc_aux = 0x 2, first_opcode == 0xDC (FCOM)
 278744  cvtps2pd with redundant RexW
 303877  valgrind doesn't support compressed debuginfo sections.
diff --git a/coregrind/m_errormgr.c b/coregrind/m_errormgr.c
index a46c6c36c2..8f6370279e 100644
--- a/coregrind/m_errormgr.c
+++ b/coregrind/m_errormgr.c
@@ -195,8 +195,8 @@ typedef
    }
    CoreSuppKind;
 
-/* Max number of callers for context in a suppression. */
-#define VG_MAX_SUPP_CALLERS  24
+/* Max number of callers for context in a suppression is
+   VG_DEEPEST_BACKTRACE. */
 
 /* For each caller specified for a suppression, record the nature of
    the caller name.  Not of interest to tools. */
@@ -410,8 +410,7 @@ static void gen_suppression(const Error* err)
    // Print stack trace elements
    UInt n_ips = VG_(get_ExeContext_n_ips)(ec);
    vg_assert(n_ips > 0);
-   if (n_ips > VG_MAX_SUPP_CALLERS)
-      n_ips = VG_MAX_SUPP_CALLERS;
+   vg_assert(n_ips <= VG_DEEPEST_BACKTRACE);
    VG_(apply_StackTrace)(printSuppForIp_nonXML,
                          text,
                          VG_(get_ExeContext_StackTrace)(ec),
@@ -1260,7 +1259,7 @@ static void load_one_suppressions_file ( Int clo_suppressions_i )
    HChar* tool_names;
    HChar* supp_name;
    const HChar* err_str = NULL;
-   SuppLoc tmp_callers[VG_MAX_SUPP_CALLERS];
+   SuppLoc tmp_callers[VG_DEEPEST_BACKTRACE];
 
    // Check it's not a directory.
    if (VG_(is_dir)( filename )) {
@@ -1289,7 +1288,7 @@ static void load_one_suppressions_file ( Int clo_suppressions_i )
       supp->count = 0;
 
       // Initialise temporary reading-in buffer.
-      for (i = 0; i < VG_MAX_SUPP_CALLERS; i++) {
+      for (i = 0; i < VG_DEEPEST_BACKTRACE; i++) {
          tmp_callers[i].ty   = NoName;
          tmp_callers[i].name_is_simple_str = False;
          tmp_callers[i].name = NULL;
@@ -1391,7 +1390,7 @@ static void load_one_suppressions_file ( Int clo_suppressions_i )
                BOMB("missing stack trace");
             }
          }
-         if (i == VG_MAX_SUPP_CALLERS)
+         if (i == VG_DEEPEST_BACKTRACE)
             BOMB("too many callers in stack trace");
          if (i > 0 && i >= VG_(clo_backtrace_size)) 
             break;