fix: valgrind doesn't filter .plt.sec calls

CODSPEED-CHANGELOG.md

@@ -4,6 +4,17 @@ This file documents changes made to Valgrind for CodSpeed integration, beyond th
 
 ## Features
 
+### Skip `.plt.sec` in `--skip-plt`
+
+**Feature**: Added support for skipping `.plt.sec` sections when using the `--skip-plt` option.
+
+**Motivation**: The `.plt.sec` section is a specialized variant of the Procedure Linkage Table (PLT) used in systems with Intel Control-flow Enforcement Technology (CET). When profiling applications using libraries compiled with it (e.g. libpython), symbols in `.plt.sec` were not skipped by the `--skip-plt` option, causing unresolved addresses to appear in profiling data (e.g., `_PySequence_Tuple` at 0x48ce4a0). Both `.plt` and `.plt.sec` sections contain only jumps to the actual function implementations, and do not have any symbols associated with those wrapper functions.
+
+**How it works**:
+- Extends the existing PLT-skipping logic to also recognize and skip `.plt.sec` sections
+- Whenever we see a function inside the `.plt.sec` section, skip it
+
+**Usage**: Enable `--skip-plt=yes` and both `.plt` and `.plt.sec` will be skipped.
 
 ### Callgrind: Inline Function Tracking
 

callgrind/fn.c

@@ -663,7 +663,7 @@ fn_node* CLG_(get_fn_node)(BB* bb)
       pure[1] = fn;
       fn->pure_cxt = CLG_(get_cxt)(pure+1);
 
-      if (bb->sect_kind == Vg_SectPLT)	
+      if (bb->sect_kind == Vg_SectPLT || bb->sect_kind == Vg_SectPLTSEC)	
 	fn->skip = CLG_(clo).skip_plt;
 
       if (VG_(strncmp)(fn->name, "_dl_runtime_resolve", 19)==0) {

coregrind/m_debuginfo/debuginfo.c

@@ -4975,6 +4975,16 @@ SizeT VG_(DebugInfo_get_plt_size)(const DebugInfo* di)
    return di->plt_present ? di->plt_size : 0; 
 }
 
+Addr VG_(DebugInfo_get_pltsec_avma)(const DebugInfo* di)
+{
+   return di->pltsec_present ? di->pltsec_avma : 0;
+}
+
+SizeT VG_(DebugInfo_get_pltsec_size)(const DebugInfo* di)
+{
+   return di->pltsec_present ? di->pltsec_size : 0;
+}
+
 Addr VG_(DebugInfo_get_gotplt_avma)(const DebugInfo* di)
 {
    return di->gotplt_present ? di->gotplt_avma : 0; 
@@ -5053,6 +5063,7 @@ const HChar* VG_(pp_SectKind)( VgSectKind kind )
       case Vg_SectPLT:     return "PLT";
       case Vg_SectOPD:     return "OPD";
       case Vg_SectGOTPLT:  return "GOTPLT";
+      case Vg_SectPLTSEC:  return "PLTSEC";
       default:             vg_assert(0);
    }
 }
@@ -5115,6 +5126,12 @@ VgSectKind VG_(DebugInfo_sect_kind)( /*OUT*/const HChar** objname, Addr a)
          res = Vg_SectPLT;
          break;
       }
+      if (di->pltsec_present
+          && di->pltsec_size > 0
+          && a >= di->pltsec_avma && a < di->pltsec_avma + di->pltsec_size) {
+         res = Vg_SectPLTSEC;
+         break;
+      }
       if (di->got_present
           && di->got_size > 0
           && a >= di->got_avma && a < di->got_avma + di->got_size) {

coregrind/m_debuginfo/priv_storage.h

@@ -905,6 +905,10 @@ struct _DebugInfo {
    Bool   plt_present;
    Addr	  plt_avma;
    SizeT  plt_size;
+   /* .plt.sec */
+   Bool   pltsec_present;
+   Addr   pltsec_avma;
+   SizeT  pltsec_size;
    /* .got */
    Bool   got_present;
    Addr   got_avma;

coregrind/m_debuginfo/readelf.c

@@ -2734,6 +2734,17 @@ Bool ML_(read_elf_object) ( struct _DebugInfo* di )
             BAD(".plt");
          }
       }
+      /* Accept .plt.sec where mapped as rx (code) - hardened PLT section */
+      if (0 == VG_(strcmp)(name, ".plt.sec")) {
+         if (inrx && !di->pltsec_present) {
+            di->pltsec_present = True;
+            di->pltsec_avma = svma + inrx->bias;
+            di->pltsec_size = size;
+            TRACE_SYMTAB("acquiring .plt.sec avma = %#lx\n", di->pltsec_avma);
+         } else {
+            BAD(".plt.sec");
+         }
+      }
 #     elif defined(VGP_ppc32_linux)
       /* Accept .plt where mapped as rw (data) */
       if (0 == VG_(strcmp)(name, ".plt")) {
@@ -2746,6 +2757,17 @@ Bool ML_(read_elf_object) ( struct _DebugInfo* di )
             BAD(".plt");
          }
       }
+      /* Accept .plt.sec where mapped as rw (data) - hardened PLT section */
+      if (0 == VG_(strcmp)(name, ".plt.sec")) {
+         if (inrw1 && !di->pltsec_present) {
+            di->pltsec_present = True;
+            di->pltsec_avma = svma + inrw1->bias;
+            di->pltsec_size = size;
+            TRACE_SYMTAB("acquiring .plt.sec avma = %#lx\n", di->pltsec_avma);
+         } else {
+            BAD(".plt.sec");
+         }
+      }
 #     elif defined(VGP_ppc64be_linux) || defined(VGP_ppc64le_linux)
       /* Accept .plt where mapped as rw (data), or unmapped */
       if (0 == VG_(strcmp)(name, ".plt")) {
@@ -2766,6 +2788,25 @@ Bool ML_(read_elf_object) ( struct _DebugInfo* di )
             BAD(".plt");
          }
       }
+      /* Accept .plt.sec where mapped as rw (data), or unmapped - hardened PLT section */
+      if (0 == VG_(strcmp)(name, ".plt.sec")) {
+         if (inrw1 && !di->pltsec_present) {
+            di->pltsec_present = True;
+            di->pltsec_avma = svma + inrw1->bias;
+            di->pltsec_size = size;
+            TRACE_SYMTAB("acquiring .plt.sec avma = %#lx\n", di->pltsec_avma);
+         } else
+         if ((!inrw1) && (!inrx) && size > 0 && !di->pltsec_present) {
+            /* File contains a .plt.sec, but it didn't get mapped.
+               Presumably it is not required on this platform.  At
+               least don't reject the situation as invalid. */
+            di->pltsec_present = True;
+            di->pltsec_avma = 0;
+            di->pltsec_size = 0;
+         } else {
+            BAD(".plt.sec");
+         }
+      }
 #     else
 #       error "Unsupported platform"
 #     endif

include/pub_tool_debuginfo.h

@@ -282,6 +282,8 @@ Addr          VG_(DebugInfo_get_bss_avma)    ( const DebugInfo *di );
 SizeT         VG_(DebugInfo_get_bss_size)    ( const DebugInfo *di );
 Addr          VG_(DebugInfo_get_plt_avma)    ( const DebugInfo *di );
 SizeT         VG_(DebugInfo_get_plt_size)    ( const DebugInfo *di );
+Addr          VG_(DebugInfo_get_pltsec_avma) ( const DebugInfo *di );
+SizeT         VG_(DebugInfo_get_pltsec_size) ( const DebugInfo *di );
 Addr          VG_(DebugInfo_get_gotplt_avma) ( const DebugInfo *di );
 SizeT         VG_(DebugInfo_get_gotplt_size) ( const DebugInfo *di );
 Addr          VG_(DebugInfo_get_got_avma)    ( const DebugInfo *di );
@@ -310,7 +312,8 @@ typedef
       Vg_SectGOT,
       Vg_SectPLT,
       Vg_SectGOTPLT,
-      Vg_SectOPD
+      Vg_SectOPD,
+      Vg_SectPLTSEC
    }
    VgSectKind;