From 4c721f24fc190d1dc935eb0bab283de7cf13182e Mon Sep 17 00:00:00 2001 From: caiyinyu Date: Tue, 28 Feb 2023 16:21:41 +0800 Subject: [PATCH] x86: Fix bug about glibc.cpu.hwcaps. Recorded in [BZ #30183]: 1. export GLIBC_TUNABLES=glibc.cpu.hwcaps=-AVX512 2. Add _dl_printf("p -- %s\n", p); just before switch(nl) in sysdeps/x86/cpu-tunables.c 3. compiled and run ./testrun.sh /usr/bin/ls you will get: p -- -AVX512 p -- LC_ADDRESS=en_US.UTF-8 p -- LC_NUMERIC=C ... The function, TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp), checks far more than it should and it should stop at end of "-AVX512". --- sysdeps/x86/cpu-tunables.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index d3e1367..772fb0c 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -107,13 +107,13 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) NOTE: the IFUNC selection may change over time. Please check all multiarch implementations when experimenting. */ - const char *p = valp->strval; + const char *p = valp->strval, *c; struct cpu_features *cpu_features = &GLRO(dl_x86_cpu_features); size_t len; do { - const char *c, *n; + const char *n; bool disable; size_t nl; @@ -283,7 +283,7 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) } p += len + 1; } - while (*p != '\0'); + while (*c != '\0'); } # if CET_ENABLED -- 2.7.4