Add valgrind-3.19.0-ld-so-strncmp.patch

Resolves: #2086540
valgrind: Missing strncmp intercept for ld.so

valgrind-3.19.0-ld-so-strncmp.patch

@@ -0,0 +1,25 @@
+commit 947388eb043ea1c44b37df94046e1eee790ad776
+Author: Mike Crowe <mac@mcrowe.com>
+Date:   Mon Sep 9 14:16:16 2019 +0100
+
+    Intercept strncmp for glibc ld.so v2.28+
+    
+    In glibc 5aad5f617892e75d91d4c8fb7594ff35b610c042 (first released in
+    v2.28) a call to strncmp was added to dl-load.c:is_dst. This causes
+    valgrind to complain about glibc's highly-optimised strncmp performing
+    sixteen-byte reads on short strings in ld.so. Let's intercept strncmp in
+    ld.so too so we use valgrind's simple version to avoid this problem.
+
+diff --git a/shared/vg_replace_strmem.c b/shared/vg_replace_strmem.c
+index 3b42b3a87..5396e83be 100644
+--- a/shared/vg_replace_strmem.c
++++ b/shared/vg_replace_strmem.c
+@@ -710,6 +710,8 @@ static inline void my_exit ( int x )
+  STRNCMP(VG_Z_LIBC_SONAME, __GI_strncmp)
+  STRNCMP(VG_Z_LIBC_SONAME, __strncmp_sse2)
+  STRNCMP(VG_Z_LIBC_SONAME, __strncmp_sse42)
++ STRNCMP(VG_Z_LD_LINUX_SO_2, strncmp)
++ STRNCMP(VG_Z_LD_LINUX_X86_64_SO_2, strncmp)
+ 
+ #elif defined(VGO_freebsd)
+  STRNCMP(VG_Z_LIBC_SONAME, strncmp)

valgrind.spec

@@ -85,6 +85,9 @@ Patch3: valgrind-3.16.0-some-stack-protector.patch
 # Add some -Wl,z,now.
 Patch4: valgrind-3.16.0-some-Wl-z-now.patch
 
+# KDE#434764 # iconv_open causes ld.so v2.28+ to execute optimised strncmp
+Patch5: valgrind-3.19.0-ld-so-strncmp.patch
+
 BuildRequires: make
 BuildRequires: glibc-devel
 
@@ -222,6 +225,7 @@ Valgrind User Manual for details.
 %patch4 -p1
 %endif
 
+%patch5 -p1
 
 %build
 # LTO triggers undefined symbols in valgrind.  Valgrind has a --enable-lto
@@ -451,6 +455,9 @@ fi
 %endif
 
 %changelog
+* Tue May 24 2022 Mark Wielaard <mjw@redhat.com>
+- Add valgrind-3.19.0-ld-so-strncmp.patch
+
 * Tue Apr 19 2022 Mark Wielaard <mjw@redhat.com> - 3.19.0-1
 - Upgrade to valgrind 3.19.0. Drop old patches.