From f51c8367685dc888a02f7304c729ed5277904aff Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Thu, 24 May 2018 14:39:18 +0200 Subject: [PATCH] Don't write beyond destination in __mempcpy_avx512_no_vzeroupper (bug 23196) When compiled as mempcpy, the return value is the end of the destination buffer, thus it cannot be used to refer to the start of it. (cherry picked from commit 9aaaab7c6e4176e61c59b0a63c6ba906d875dc0e) --- ChangeLog | 9 +++++++++ NEWS | 7 +++++++ string/test-mempcpy.c | 1 + sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S | 5 +++-- 4 files changed, 20 insertions(+), 2 deletions(-) diff --git a/string/test-mempcpy.c b/string/test-mempcpy.c index c08fba8..d98ecdd 100644 --- a/string/test-mempcpy.c +++ b/string/test-mempcpy.c @@ -18,6 +18,7 @@ . */ #define MEMCPY_RESULT(dst, len) (dst) + (len) +#define MIN_PAGE_SIZE 131072 #define TEST_MAIN #define TEST_NAME "mempcpy" #include "test-string.h" diff --git a/sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S b/sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S index 23c0f7a..effc3ac 100644 --- a/sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S +++ b/sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S @@ -336,6 +336,7 @@ L(preloop_large): vmovups (%rsi), %zmm4 vmovups 0x40(%rsi), %zmm5 + mov %rdi, %r11 /* Align destination for access with non-temporal stores in the loop. */ mov %rdi, %r8 and $-0x80, %rdi @@ -366,8 +367,8 @@ L(gobble_256bytes_nt_loop): cmp $256, %rdx ja L(gobble_256bytes_nt_loop) sfence - vmovups %zmm4, (%rax) - vmovups %zmm5, 0x40(%rax) + vmovups %zmm4, (%r11) + vmovups %zmm5, 0x40(%r11) jmp L(check) L(preloop_large_bkw): -- 2.9.3