MALLOC_CHECK_ and MALLOC_PERTURB_ environment variables have been replaced in glibc 2.34 by GLIBC_TUNABLES settings[1][2]. In addition the new glibc requires that you preload a new library called libc_malloc_debug.so.0 to get these features. These features never worked in non-glibc (but the environment variables are ignored). Only define MALLOC_* environment variables when we detect glibc < 2.34, using the ordinary glibc macros[3]. For glibc >= 2.34, use the new library and GLIBC_TUNABLES. Note this relies on LD_PRELOAD warning but otherwise not breaking if a preload library does not exist. [1] https://www.gnu.org/software/libc/manual/html_node/Memory-Allocation-Tuna... [2] https://sourceware.org/pipermail/libc-alpha/2021-August/129718.html [3] https://sourceforge.net/p/predef/wiki/Libraries/ Thanks: Eric Blake --- configure.ac | 24 ++++++++++++++++++++++++ tests/Makefile.am | 23 +++++++++++++++++------ 2 files changed, 41 insertions(+), 6 deletions(-) diff --git a/configure.ac b/configure.ac index 9eb9b174..bdb56b37 100644 --- a/configure.ac +++ b/configure.ac @@ -569,6 +569,30 @@ AS_IF([test "x$is_windows" = "xyes"],[ AC_SEARCH_LIBS([getaddrinfo], [network socket]) +dnl Does this libc have MALLOC_CHECK_ and MALLOC_PERTURB_ (both glibc) +dnl and does the feature require libc_malloc_debug.so (glibc >= 2.34)? +AC_MSG_CHECKING([if this is glibc]) +AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ +#include <limits.h> +#ifndef __GLIBC__ +#error "not glibc" +#endif + ]])], [is_glibc=yes], [is_glibc=no] +) +AC_MSG_RESULT([$is_glibc]) +AM_CONDITIONAL([HAVE_GLIBC], [test "x$is_glibc" = "xyes"]) + +AC_MSG_CHECKING([if this is glibc >= 2.34]) +AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ +#include <limits.h> +#if !defined(__GLIBC__) || __GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 34) +#error "not glibc 2.34" +#endif + ]])], [is_glibc_234=yes], [is_glibc_234=no] +) +AC_MSG_RESULT([$is_glibc_234]) +AM_CONDITIONAL([HAVE_GLIBC_234], [test "x$is_glibc_234" = "xyes"]) + dnl Check for SELinux socket labelling (optional). PKG_CHECK_MODULES([LIBSELINUX], [libselinux], [ AC_SUBST([LIBSELINUX_CFLAGS]) diff --git a/tests/Makefile.am b/tests/Makefile.am index a6e27d95..5919187b 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -61,21 +61,32 @@ EXTRA_DIST = README.tests EXTRA_PROGRAMS = # Use the 'direct' backend, and ensure maximum libguestfs debugging. -# # Enable libnbd debugging. -# -# Enable malloc-check as a cheap way to find some use-after-free and -# uninitialized read problems when using glibc, and doesn't affect -# normal operation or other libc. TESTS_ENVIRONMENT = \ SRCDIR=$(srcdir) \ LIBGUESTFS_ATTACH_METHOD=appliance \ LIBGUESTFS_DEBUG=1 \ LIBGUESTFS_TRACE=1 \ LIBNBD_DEBUG=1 \ + $(NULL) + +# Enable malloc-check as a cheap way to find some use-after-free and +# uninitialized read problems when using glibc, and doesn't affect +# normal operation or other libc. +random = $(shell bash -c 'echo $$(( 1 + (RANDOM & 255) ))') +if HAVE_GLIBC_234 +TESTS_ENVIRONMENT += \ + LD_PRELOAD="$${LD_PRELOAD:+"$$LD_PRELOAD:"}$(libdir)/libc_malloc_debug.so.0" \ + GLIBC_TUNABLES=glibc.malloc.check=1:glibc.malloc.perturb=$(random) \ + $(NULL) +else +if HAVE_GLIBC +TESTS_ENVIRONMENT += \ MALLOC_CHECK_=1 \ - MALLOC_PERTURB_=$(shell bash -c 'echo $$(( 1 + (RANDOM & 255) ))') \ + MALLOC_PERTURB_=$(random) \ $(NULL) +endif +endif if !IS_WINDOWS # Ensure we're testing the local copy by running everything through -- 2.32.0

On Sun, Aug 22, 2021 at 01:57:16PM +0100, Richard W.M. Jones wrote: Good point about reducing the cross-interference between glibc and what valgrind wants to prove. I'm fine if we permanently disable glibc's malloc checking when we know we are running under valgrind. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org