From: Florian Weimer <fweimer@redhat.com>
Date: Tue, 17 Dec 2024 17:12:03 +0000 (+0100)
Subject: x86: Avoid integer truncation with large cache sizes (bug 32470)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fbcde5ea4613bc04c174e9adcca9f6eb5e308d79;p=thirdparty%2Fglibc.git

x86: Avoid integer truncation with large cache sizes (bug 32470)

Some hypervisors report 1 TiB L3 cache size.  This results
in some variables incorrectly getting zeroed, causing crashes
in memcpy/memmove because invariants are violated.

(cherry picked from commit 61c3450db96dce96ad2b24b4f0b548e6a46d68e5)
---

diff --git a/NEWS b/NEWS
index 30a3eaaf47..32cba994c9 100644
--- a/NEWS
+++ b/NEWS
@@ -106,6 +106,7 @@ The following bugs are resolved with this release:
   [32052] Name space violation in fortify wrappers
   [32137] libio: Attempt wide backup free only for non-legacy code
   [32231] elf: Change ldconfig auxcache magic number
+  [32470] x86: Avoid integer truncation with large cache sizes
 
 Version 2.36
 
diff --git a/sysdeps/x86/dl-cacheinfo.h b/sysdeps/x86/dl-cacheinfo.h
index d95c1efa2c..72ee1788e3 100644
--- a/sysdeps/x86/dl-cacheinfo.h
+++ b/sysdeps/x86/dl-cacheinfo.h
@@ -901,12 +901,12 @@ dl_init_cacheinfo (struct cpu_features *cpu_features)
 
 #if HAVE_TUNABLES
   /* NB: The REP MOVSB threshold must be greater than VEC_SIZE * 8.  */
-  unsigned int minimum_rep_movsb_threshold;
+  unsigned long int minimum_rep_movsb_threshold;
 #endif
   /* NB: The default REP MOVSB threshold is 4096 * (VEC_SIZE / 16) for
      VEC_SIZE == 64 or 32.  For VEC_SIZE == 16, the default REP MOVSB
      threshold is 2048 * (VEC_SIZE / 16).  */
-  unsigned int rep_movsb_threshold;
+  unsigned long int rep_movsb_threshold;
   if (CPU_FEATURE_USABLE_P (cpu_features, AVX512F)
       && !CPU_FEATURE_PREFERRED_P (cpu_features, Prefer_No_AVX512))
     {