Redo the crafted libc.so.6 symbol table for valgrind (#1965374)

glibc.spec

@@ -97,7 +97,7 @@
 Summary: The GNU libc libraries
 Name: glibc
 Version: %{glibcversion}
-Release: 20%{?dist}
+Release: 21%{?dist}
 
 # In general, GPLv2+ is used by programs, LGPLv2+ is used for
 # libraries.
@@ -150,6 +150,11 @@ rpm.define("__debug_install_post bash " .. wrapper
   .. " " .. sysroot .. " " .. original)
 }
 
+# The wrapper script relies on the fact that debugedit does not change
+# build IDs.
+%define _no_recompute_build_ids 1
+%undefine _unique_build_ids
+
 ##############################################################################
 # Patches:
 # - See each individual patch file for origin and upstream status.
@@ -2184,6 +2189,9 @@ fi
 %files -f compat-libpthread-nonshared.filelist -n compat-libpthread-nonshared
 
 %changelog
+* Thu Jun 17 2021 Florian Weimer <fweimer@redhat.com> - 2.33.9000-21
+- Redo the crafted libc.so.6 symbol table for valgrind (#1965374)
+
 * Thu Jun 17 2021 Florian Weimer <fweimer@redhat.com> - 2.33.9000-20
 - Remove .symtab from libc.so.6 again (#1965374)
 

wrap-find-debuginfo.sh

@@ -9,10 +9,14 @@
 # LDSO-PATH file, followed by note merging and DWZ compression.
 # As a result, ld.so has (mostly) unchanged debuginfo even
 # after debuginfo extraction.
+#
+# For libc.so.6, a set of strategic symbols is preserved in .symtab
+# that are frequently used in valgrind suppressions.
 
 set -ex
 
 ldso_tmp="$(mktemp)"
+libc_tmp="$(mktemp)"
 
 # Prefer a separately installed debugedit over the RPM-integrated one.
 if command -v debugedit >/dev/null ; then
@@ -22,7 +26,7 @@ else
 fi
 
 cleanup () {
-    rm -f "$ldso_tmp"
+    rm -f "$ldso_tmp" "$libc_tmp"
 }
 trap cleanup 0
 
@@ -43,21 +47,94 @@ for ldso_candidate in `find "$sysroot_path" -regextype posix-extended \
     fi
 done
 
-# Preserve the original file.
+# libc.so.6 always uses this name, so it is simpler to locate.
+libc_path=
+for libc_candidate in `find "$sysroot_path" -name libc.so.6`; do
+    if test -z "$libc_path" ; then
+	libc_path="$libc_candidate"
+    else
+	echo "error: multiple libc.so.6 candidates: $libc_path, $libc_candidate"
+	exit 1
+    fi
+done
+
+
+# Preserve the original files.
 cp "$ldso_path" "$ldso_tmp"
+cp "$libc_path" "$libc_tmp"
 
 # Run the debuginfo extraction.
 "$script_path" "$@"
 
-# Restore the original file.
+# Restore the original files.
 cp "$ldso_tmp" "$ldso_path"
+cp "$libc_tmp" "$libc_path"
 
 # Reduce the size of notes.  Primarily for annobin.
 objcopy --merge-notes "$ldso_path"
+objcopy --merge-notes "$libc_path"
 
-# Rewrite the source file paths to match the extracted locations.
+# libc.so.6: Reduce to strategic symbols needed by valgrind.
-# First compute the arguments for invoking debugedit.  See
+# pthread_create is needed to trigger loading of libthread_db in GDB.
-# find-debuginfo.sh.
+# (Debuginfo is gone after this, so no need to optimize it.)
+strip \
+    -K __GI___rawmemchr \
+    -K __GI___strcasecmp_l \
+    -K __GI___strncasecmp_l \
+    -K __GI_memchr \
+    -K __GI_memcmp \
+    -K __GI_memcpy \
+    -K __GI_memmove \
+    -K __GI_mempcpy \
+    -K __GI_stpcpy \
+    -K __GI_strcasecmp \
+    -K __GI_strcasecmp_l \
+    -K __GI_strcat \
+    -K __GI_strchr \
+    -K __GI_strcmp \
+    -K __GI_strcpy \
+    -K __GI_strcspn \
+    -K __GI_strlen \
+    -K __GI_strncasecmp \
+    -K __GI_strncasecmp_l \
+    -K __GI_strncmp \
+    -K __GI_strncpy \
+    -K __GI_strnlen \
+    -K __GI_strrchr \
+    -K __GI_wcsnlen \
+    -K __GI_wmemchr \
+    -K __memcmp_sse2 \
+    -K __memcmp_sse4_1 \
+    -K __memcpy_avx_unaligned_erms \
+    -K __memcpy_chk \
+    -K __memcpy_sse2 \
+    -K __memmove_chk \
+    -K __stpcpy_chk \
+    -K __stpcpy_sse2 \
+    -K __stpcpy_sse2_unaligned \
+    -K __strchr_sse2 \
+    -K __strchr_sse2_no_bsf \
+    -K __strcmp_sse2 \
+    -K __strcmp_sse42 \
+    -K __strcpy_chk \
+    -K __strlen_sse2 \
+    -K __strlen_sse2_no_bsf \
+    -K __strlen_sse42 \
+    -K __strncmp_sse2 \
+    -K __strncmp_sse42 \
+    -K __strncpy_sse2 \
+    -K __strncpy_sse2_unaligned \
+    -K __strrchr_sse2 \
+    -K __strrchr_sse2_no_bsf \
+    -K __strrchr_sse42 \
+    -K __strstr_sse2 \
+    -K __strstr_sse42 \
+    -K pthread_create \
+    "$libc_path"
+
+# ld.so: Rewrite the source file paths to match the extracted
+# locations.  First compute the arguments for invoking debugedit.
+# See find-debuginfo.sh.
 debug_dest_name="/usr/src/debug"
 last_arg=
 while true ; do