Accepting request 1273668 from devel:libraries:c_c++

OBS-URL: https://build.opensuse.org/request/show/1273668
OBS-URL: https://build.opensuse.org/package/show/openSUSE:Factory/hwloc?expand=0&rev=34

0001-x86-work-around-legacy_max_proc-being-0-while-HTT-fe.patch

@@ -0,0 +1,54 @@
+From 77495cecad7178ccd73ad4962780328f079a0e65 Mon Sep 17 00:00:00 2001
+From: Brice Goglin <Brice.Goglin@inria.fr>
+Date: Thu, 24 Apr 2025 09:08:08 +0200
+Subject: [PATCH] x86: work around legacy_max_proc being 0 while HTT feature
+ bit is set
+
+The Intel manual says that legacy_max_proc (CPUID.1.EBX[16-23]) is valid
+if CPUID.1.EDX.HTT[bit 28] is set.
+AMD (at least recent ones) don't say anything about it being invalid.
+
+Unfortunately some Qemu config may keep the former at 0 with the latter set.
+At least this happens when libvirt passes -cpu EPYC-Rome,ht=on to Qemu
+(which sets the HTT bit), and -smp 32,maxcpus=48,sockets=48,cores=1,threads=1
+says each CPU is single threaded (which keeps legacy_max_log_proc to 0).
+This config comes from https://bugzilla.opensuse.org/show_bug.cgi?id=1236038
+
+Calling flsl on this invalid mask leads to undefined behavior and some division
+by zero later (depending on the compiler).
+
+Check whether legacy_max_proc is 0 before using it.
+If 0, assume legacy_max_log_proc is 1, just like we did when HTT is unset.
+
+Thanks to Georg Pfuetzenreuter for the report
+and Anthony Iliopoulos for the debugging.
+
+Refs #714
+
+Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
+---
+ hwloc/topology-x86.c | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/hwloc/topology-x86.c b/hwloc/topology-x86.c
+index a267ded49..5f63fc178 100644
+--- a/hwloc/topology-x86.c
++++ b/hwloc/topology-x86.c
+@@ -653,7 +653,13 @@ static void look_proc(struct hwloc_backend *backend, struct procinfo *infos, uns
+   cpuid_or_from_dump(&eax, &ebx, &ecx, &edx, src_cpuiddump);
+   infos->apicid = ebx >> 24;
+   if (edx & (1 << 28)) {
+-    legacy_max_log_proc = 1 << hwloc_flsl(((ebx >> 16) & 0xff) - 1);
++    unsigned ebx_16_23 = (ebx >> 16) & 0xff;
++    if (ebx_16_23) {
++      legacy_max_log_proc = 1 << hwloc_flsl(ebx_16_23 - 1);
++    } else {
++      hwloc_debug("HTT bit set in CPUID 0x01.edx, but legacy_max_proc = 0 in ebx, assuming legacy_max_log_proc = 1\n");
++      legacy_max_log_proc = 1;
++    }
+   } else {
+     hwloc_debug("HTT bit not set in CPUID 0x01.edx, assuming legacy_max_log_proc = 1\n");
+     legacy_max_log_proc = 1;
+-- 
+2.48.1
+

hwloc.changes

@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Mon Apr 28 07:32:19 UTC 2025 - Thomas Blume <Thomas.Blume@suse.com>
+
+- fix division by zero exception with recent versions of GCC 
+  (bsc#1236038)
+  * add 0001-x86-work-around-legacy_max_proc-being-0-while-HTT-fe.patch
+
 -------------------------------------------------------------------
 Tue Jan  7 08:56:48 UTC 2025 - Thomas Blume <Thomas.Blume@suse.com>
 

hwloc.spec

@@ -35,6 +35,8 @@ Summary:        Portable Hardware Locality
 License:        BSD-3-Clause
 URL:            https://www.open-mpi.org/projects/hwloc/
 Source0:        https://download.open-mpi.org/release/hwloc/v2.11/hwloc-%{version}.tar.bz2
+Patch0:         0001-x86-work-around-legacy_max_proc-being-0-while-HTT-fe.patch
+
 BuildRequires:  autoconf
 BuildRequires:  automake
 BuildRequires:  doxygen
@@ -137,6 +139,7 @@ HW accelerators from AMD and NVIDIA
 
 %prep
 %setup -q
+%autopatch -p1
 
 %build
 autoreconf -fvi