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From: "hjl.tools at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug string/25933] Off by one error in __strncmp_avx2 when length=VEC_SIZE*4 and strings are at page boundaries can cause a segfault
Date: Sun, 07 Jun 2020 18:30:45 +0000 [thread overview]
Message-ID: <bug-25933-131-fahslx5cNb@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-25933-131@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=25933
--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Sunil Pandey from comment #4)
> Created attachment 12601 [details]
> strncmp_avx2 patch for pr25933
>
> Tested attached patch on
>
> https://gitlab.com/x86-glibc/glibc/-/commits/users/hjl/pr25933/master
Looks good. Please try this
diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S
b/sysdeps/x86_64/multiarch/strcmp-avx2.S
index 48d03a9f46..dabc3e7590 100644
--- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
+++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
@@ -256,6 +256,11 @@ L(next_3_vectors):
vpmovmskb %ymm0, %ecx
testl %ecx, %ecx
jne L(return_3_vec_size)
+# ifdef USE_AS_STRNCMP
+ /* Check if VEC_SIZE * 4 already exceeded max compare count %r11 */
+ cmpq $(VEC_SIZE * 4), %r11
+ jbe L(zero)
+# endif
L(main_loop_header):
leaq (VEC_SIZE * 4)(%rdi), %rdx
movl $PAGE_SIZE, %ecx
--
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next prev parent reply other threads:[~2020-06-07 18:30 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-06 23:49 [Bug string/25933] New: " dpmendenhall at gmail dot com
2020-05-07 0:46 ` [Bug string/25933] " hjl.tools at gmail dot com
2020-05-07 2:23 ` dpmendenhall at gmail dot com
2020-05-07 13:07 ` adhemerval.zanella at linaro dot org
2020-05-07 14:26 ` hjl.tools at gmail dot com
2020-05-08 23:03 ` lsg.tools at gmail dot com
2020-05-19 16:52 ` skpgkp2 at gmail dot com
2020-05-19 17:39 ` hjl.tools at gmail dot com
2020-06-07 18:15 ` skpgkp2 at gmail dot com
2020-06-07 18:30 ` hjl.tools at gmail dot com [this message]
2020-06-07 20:03 ` skpgkp2 at gmail dot com
2020-06-07 20:43 ` hjl.tools at gmail dot com
2020-06-07 21:46 ` skpgkp2 at gmail dot com
2020-06-07 21:58 ` hjl.tools at gmail dot com
2020-06-07 22:01 ` hjl.tools at gmail dot com
2020-06-07 23:05 ` hjl.tools at gmail dot com
2020-06-08 1:26 ` hjl.tools at gmail dot com
2020-06-09 2:30 ` hjl.tools at gmail dot com
2020-06-10 8:21 ` skpgkp2 at gmail dot com
2020-06-10 13:11 ` hjl.tools at gmail dot com
2020-06-11 2:03 ` skpgkp2 at gmail dot com
2020-06-11 2:04 ` skpgkp2 at gmail dot com
2020-06-11 2:06 ` skpgkp2 at gmail dot com
2020-06-11 2:08 ` skpgkp2 at gmail dot com
2020-06-11 2:11 ` skpgkp2 at gmail dot com
2020-06-11 16:05 ` hjl.tools at gmail dot com
2020-06-13 11:27 ` hjl.tools at gmail dot com
2020-06-13 11:27 ` hjl.tools at gmail dot com
2020-06-13 11:27 ` hjl.tools at gmail dot com
2020-06-13 11:28 ` hjl.tools at gmail dot com
2020-06-13 11:28 ` hjl.tools at gmail dot com
2020-06-13 11:28 ` hjl.tools at gmail dot com
2020-07-04 16:47 ` cvs-commit at gcc dot gnu.org
2020-07-04 16:52 ` cvs-commit at gcc dot gnu.org
2020-07-04 17:02 ` cvs-commit at gcc dot gnu.org
2020-07-04 17:21 ` cvs-commit at gcc dot gnu.org
2020-07-04 17:22 ` hjl.tools at gmail dot com
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