https://bugs.kde.org/show_bug.cgi?id=383010
--- Comment #107 from Michał Dec <moog...@gmail.com> --- (In reply to Mark Wielaard from comment #103) > Normally glibc uses ifuncs which check whether avx512 is available. Since > valgrind doesn't advertise avx512 being available glibc should normally not > use it. Do you know why it does? How is your glibc build? What error do you > see under valgrind? > Do you know why it does? I don't know, that's why I'm asking. From what I understand in my next answer, I should disable multiarch and recompile glibc without AVX-512. But I don't wanna reboot for nothing. I have an AM5 system and I really hate rebooting it, it takes forever. > How is your glibc build? At the time of writing, this is the recipe for building the version of glibc considered stable on amd64: https://gitweb.gentoo.org/repo/gentoo.git/tree/sys-libs/glibc/glibc-2.39-r6.ebuild?id=9adf7dbf124f3810b77c28a04f7dd7995d238854 The flags I have enabled in my build are pretty common ones: cet multiarch ssp stack-realign > What error do you see under valgrind? ``` vex amd64->IR: unhandled instruction bytes: 0x62 0xD2 0xFD 0x28 0x7C 0xC0 0x48 0x89 0xC6 0x31 vex amd64->IR: REX=0 REX.W=0 REX.R=0 REX.X=0 REX.B=0 vex amd64->IR: VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=NONE vex amd64->IR: PFX.66=0 PFX.F2=0 PFX.F3=0 ==28914== valgrind: Unrecognised instruction at address 0x484f0cf. ==28914== at 0x484F0CF: memset (vg_replace_strmem.c:1390) ==28914== by 0x4A47F71: memset (string_fortified.h:59) ==28914== by 0x4A47F71: CRYPTO_zalloc (mem.c:224) ==28914== by 0x4A5A220: CRYPTO_THREAD_lock_new (threads_pthread.c:684) ==28914== by 0x4B330FC: do_rand_init (rand_lib.c:51) ==28914== by 0x4B330FC: do_rand_init_ossl_ (rand_lib.c:48) ==28914== by 0x4DE340F: __pthread_once_slow (pthread_once.c:116) ==28914== by 0x4DE3526: pthread_once@@GLIBC_2.34 (pthread_once.c:143) ==28914== by 0x4A5A31C: CRYPTO_THREAD_run_once (threads_pthread.c:786) ==28914== by 0x4B33B4C: RAND_get_rand_method (rand_lib.c:190) ==28914== by 0x4B347DC: RAND_bytes_ex (rand_lib.c:368) ==28914== by 0x10996B: (a function that calls RAND_bytes) (src.c:191) ==28914== by 0x109427: main (src.c:516) ``` I've ran this program through valgrind on a machine that doesn't have AVX-512, and it runs fine. No leaks, not even a single complaint about uninitialized variables being read. -- You are receiving this mail because: You are watching all bug changes.
