From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x532.google.com (mail-ed1-x532.google.com [IPv6:2a00:1450:4864:20::532]) by sourceware.org (Postfix) with ESMTPS id 3E18A3858D33 for ; Tue, 10 Jan 2023 23:03:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 3E18A3858D33 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-ed1-x532.google.com with SMTP id b4so346044edf.0 for ; Tue, 10 Jan 2023 15:03:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=BI0M6NKZCwV4+YTWsA0dKDppI1w0WB6HBqC0iOUUb8k=; b=FWk2Zyj2V9hB7uAykJZHK9o/cIEil8CNiKhBJr7wHfXYrnwsFisb2UBpw+UVIObR3i h7BOu5Pz2/FGWZl+t/APC+kPMosN/q/n/sg2zpth5/3gNO35Mr9E5L5oJdjVg4ZEzyrh ivFoR685uhvhQ6o/mOWjoa8dsga5SGh9xBNSLomdYEvWoNOFRsM/SAQJqhzwivN1cqmH 9f376GuyG+L6EAKA/IP66gz6eo/8sH2Flk+QA6olDcCXrFep8ShPuAW+dJ2uJSpbGt3g 7nlSOwKSdVEnH2KyQ+ZQuv00KOY2808mcTIM1Um/8aYmg52ieYGZZtxCqp8aQ193i98f Bfzw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=BI0M6NKZCwV4+YTWsA0dKDppI1w0WB6HBqC0iOUUb8k=; b=1OL5TMBdAF7o0ktWtGgdrFrpCERri4IFGgIVmNORR/w1OwHu7VwExag1YSNBbNnDXY apAzwzzyVCI+wlp+9QrddrBEg85Txbzyf3DgT5d6dBy+g9J0TdXd4/K1BY3L6YGbIwwA fr9KbGIZR/+0LfT6qY04ZaF0QSwZhX1bXDqnqcs6WGsBuSIGqoTAdwn50Wb5Vo5jYCY2 SHgIfHZLXMPfssoeW0VN1DG0PvY4Q+Tj1tuPW3vyXpyo4HD5mUeZVl77mv6JVpnnClPw 5rSL5c5VSi7+fRfb6TJ44dpXc5pLvuix9/ksdqYbY4f71Ym+BgWEv5ne8VUQXZpF3e3o ndXw== X-Gm-Message-State: AFqh2kqJLsv6zXUk7vGSwk27X3guBo5+oY1egUwSbDPPLZl3bvPnsZVF FwSk2tpjh8dtUwz0lSSeuPsPG7YRprlk4LHE2eBvTpTa X-Google-Smtp-Source: AMrXdXuA3d1TqHw5lsF5lg07/pSPWKIlJese/HjZg7SZlhC4EUS1m63gAkeYK/9BjpLkpPh/kHKj16SUWVKjaxi+S0w= X-Received: by 2002:a05:6402:2408:b0:47b:2514:f2e7 with SMTP id t8-20020a056402240800b0047b2514f2e7mr8655582eda.142.1673391792203; Tue, 10 Jan 2023 15:03:12 -0800 (PST) MIME-Version: 1.0 References: <20221219192726.999818-1-goldstein.w.n@gmail.com> <20221219192726.999818-2-goldstein.w.n@gmail.com> In-Reply-To: From: Noah Goldstein Date: Tue, 10 Jan 2023 15:03:00 -0800 Message-ID: Subject: Re: [PATCH v1 2/2] nptl: Add a testcase for inputs racey to {w}memcmp{eq} BZ #29863 To: libc-alpha@sourceware.org Cc: hjl.tools@gmail.com, carlos@systemhalted.org Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-9.4 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,GIT_PATCH_0,KAM_NUMSUBJECT,KAM_SHORT,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Thu, Dec 29, 2022 at 8:41 AM Noah Goldstein wrote: > > On Mon, Dec 19, 2022 at 11:28 AM Noah Goldstein wrote: > > > > On Mon, Dec 19, 2022 at 11:27 AM Noah Goldstein wrote: > > > > > > Add test that modifies data as {w}memcmp{eq} runs (creating a race > > > condition). Failures from this tests do not inherently mean the > > > {w}memcmp{eq} implementation is buggy, but is at the very least > > > something we should be aware of. > > > > > > Success is no SIGSEGV. Failure is a SIGSEGV. > > > > > > Verified test failed 10/10 times without: > > > > > > commit b712be52645282c706a5faa038242504feb06db5 > > > Author: Noah Goldstein > > > Date: Wed Dec 14 10:52:10 2022 -0800 > > > > > > x86: Prevent SIGSEGV in memcmp-sse2 when data is concurrently modified [BZ #29863] > > > > > > And passes with the fix. > > > > NB: Forget tag "Co-authored-by: H.J. Lu ", > > will add before commit or next version if more revisions are needed. > > > --- > > > nptl/Makefile | 7 ++ > > > nptl/tst-memcmp-race.c | 149 +++++++++++++++++++++++++++++++++++++++ > > > nptl/tst-memcmpeq-race.c | 19 +++++ > > > nptl/tst-wmemcmp-race.c | 20 ++++++ > > > 4 files changed, 195 insertions(+) > > > create mode 100644 nptl/tst-memcmp-race.c > > > create mode 100644 nptl/tst-memcmpeq-race.c > > > create mode 100644 nptl/tst-wmemcmp-race.c > > > > > > diff --git a/nptl/Makefile b/nptl/Makefile > > > index fc955cd604..5f56bdc80a 100644 > > > --- a/nptl/Makefile > > > +++ b/nptl/Makefile > > > @@ -285,6 +285,8 @@ tests = \ > > > tst-exec4 \ > > > tst-exec5 \ > > > tst-initializers1 $(addprefix tst-initializers1-,c89 gnu89 c99 gnu99 c11 gnu11) \ > > > + tst-memcmp-race \ > > > + tst-memcmpeq-race \ > > > tst-minstack-cancel \ > > > tst-minstack-exit \ > > > tst-minstack-throw \ > > > @@ -348,8 +350,13 @@ tests = \ > > > tst-thread_local1 \ > > > tst-tsd3 \ > > > tst-tsd4 \ > > > + tst-wmemcmp-race \ > > > # tests > > > > > > +CFLAGS-tst-memcmp-race.c += -O0 > > > +CFLAGS-tst-memcmpeq-race.c += -O0 > > > +CFLAGS-tst-wmemcmp-race.c += -O0 > > > + > > > tests-nolibpthread = \ > > > tst-pthread_exit-nothreads \ > > > tst-pthread_exit-nothreads-static \ > > > diff --git a/nptl/tst-memcmp-race.c b/nptl/tst-memcmp-race.c > > > new file mode 100644 > > > index 0000000000..56e62b2f7b > > > --- /dev/null > > > +++ b/nptl/tst-memcmp-race.c > > > @@ -0,0 +1,149 @@ > > > +/* Test case for memcmp with race condition. > > > + Copyright (C) 2022 Free Software Foundation, Inc. > > > + This file is part of the GNU C Library. > > > + > > > + The GNU C Library is free software; you can redistribute it and/or > > > + modify it under the terms of the GNU Lesser General Public > > > + License as published by the Free Software Foundation; either > > > + version 2.1 of the License, or (at your option) any later version. > > > + > > > + The GNU C Library is distributed in the hope that it will be useful, > > > + but WITHOUT ANY WARRANTY; without even the implied warranty of > > > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > > + Lesser General Public License for more details. > > > + > > > + You should have received a copy of the GNU Lesser General Public > > > + License along with the GNU C Library; if not, see > > > + . */ > > > + > > > +/* Verify that there is no segfault when one thread is updating the > > > + memory block of memcmp and the other thread is doing memcmp. > > > + > > > + NOTE: This test failing does not automatically mean the > > > + {w}memcmp{eq} is incorrect. This is testing UB and behavior that > > > + is supported. That being said, users may expect that the mem* > > > + functions never access out of bounds data (even with data races) > > > + and we should be aware of the cases when we do. */ > > > + > > > +#define TEST_MAIN > > > +#define MIN_PAGE_SIZE 4096 > > > + > > > +#ifdef TEST_MEMCMPEQ > > > +# define MEMCMP __memcmpeq > > > +# define TEST_NAME "__memcmpeq" > > > +#elif defined WIDE > > > +# define MEMCMP wmemcmp > > > +# define TEST_NAME "wmemcmp" > > > +#else > > > +# define MEMCMP memcmp > > > +# define TEST_NAME "memcmp" > > > +#endif > > > + > > > +#ifdef WIDE > > > +# define MEMSET wmemset > > > +# define CHAR wchar_t > > > +#else > > > +# define MEMSET memset > > > +# define CHAR char > > > +#endif > > > + > > > +#include > > > +#include > > > +#include > > > +#include > > > +#include > > > + > > > +#define NUM_THREADS 2 > > > +#define LOOP1 10000 > > > +#define LOOP2 1000000 > > > + > > > +typedef int (*proto_t) (const CHAR *, const CHAR *, size_t); > > > + > > > +IMPL (MEMCMP, 1) > > > + > > > +struct arg > > > +{ > > > + proto_t func; > > > + CHAR *a; > > > + CHAR *b; > > > + size_t len; > > > + size_t wpos; > > > + int todo; > > > +}; > > > + > > > +static void * > > > +childThread (void *tArgs) > > > +{ > > > + struct arg *args = (struct arg *) tArgs; > > > + int i; > > > + if (0 == args->todo % 2) > > > + { > > > + for (i = 0; i < LOOP1; i++) > > > + { > > > + volatile int result = args->func (args->a, args->b, args->len); > > > + (void)(result); > > > + } > > > + } > > > + else > > > + { > > > + for (i = 0; i < LOOP2; i++) > > > + args->a[args->wpos] = i & 1; > > > + args->a[args->wpos] = 1; > > > + } > > > + return NULL; > > > +} > > > + > > > +static void > > > +do_one_test (proto_t func, size_t len) > > > +{ > > > + int r; > > > + if (len * sizeof (CHAR) > page_size) > > > + return; > > > + for (r = 0; r < 2; ++r) > > > + { > > > + size_t wpos; > > > + for (wpos = 1; wpos < 128 && wpos <= len; wpos = wpos + wpos + 1) > > > + { > > > + int i; > > > + size_t off; > > > + pthread_t threads[NUM_THREADS]; > > > + struct arg a[NUM_THREADS]; > > > + > > > + off = r ? (page_size - len * sizeof (CHAR)) : 0; > > > + for (i = 0; i < NUM_THREADS; ++i) > > > + { > > > + a[i].func = func; > > > + a[i].a = (CHAR *) (buf1 + off); > > > + a[i].b = (CHAR *) (buf2 + off); > > > + a[i].len = len; > > > + a[i].wpos = len - wpos; > > > + a[i].todo = i; > > > + threads[i] = xpthread_create (NULL, childThread, (void *) &a[i]); > > > + } > > > + > > > + for (i = 0; i < NUM_THREADS; ++i) > > > + xpthread_join (threads[i]); > > > + } > > > + } > > > +} > > > + > > > +int > > > +test_main (void) > > > +{ > > > + test_init (); > > > + > > > + MEMSET ((CHAR *) buf1, 1, page_size / sizeof (CHAR)); > > > + MEMSET ((CHAR *) buf2, 1, page_size / sizeof (CHAR)); > > > + for (size_t i = 1; i <= 1024; i += i) > > > + { > > > + FOR_EACH_IMPL (impl, 0) > > > + { > > > + do_one_test ((proto_t) impl->fn, i); > > > + do_one_test ((proto_t) impl->fn, i + 1); > > > + do_one_test ((proto_t) impl->fn, i - 1); > > > + } > > > + } > > > + return 0; > > > +} > > > + > > > +#include > > > diff --git a/nptl/tst-memcmpeq-race.c b/nptl/tst-memcmpeq-race.c > > > new file mode 100644 > > > index 0000000000..7088928f49 > > > --- /dev/null > > > +++ b/nptl/tst-memcmpeq-race.c > > > @@ -0,0 +1,19 @@ > > > +/* Test case for __memcmpeq with race condition. > > > + Copyright (C) 2022 Free Software Foundation, Inc. > > > + This file is part of the GNU C Library. > > > + > > > + The GNU C Library is free software; you can redistribute it and/or > > > + modify it under the terms of the GNU Lesser General Public > > > + License as published by the Free Software Foundation; either > > > + version 2.1 of the License, or (at your option) any later version. > > > + > > > + The GNU C Library is distributed in the hope that it will be useful, > > > + but WITHOUT ANY WARRANTY; without even the implied warranty of > > > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > > + Lesser General Public License for more details. > > > + > > > + You should have received a copy of the GNU Lesser General Public > > > + License along with the GNU C Library; if not, see > > > + . */ > > > +#define TEST_MEMCMPEQ 1 > > > +#include "tst-memcmp-race.c" > > > diff --git a/nptl/tst-wmemcmp-race.c b/nptl/tst-wmemcmp-race.c > > > new file mode 100644 > > > index 0000000000..8278f71842 > > > --- /dev/null > > > +++ b/nptl/tst-wmemcmp-race.c > > > @@ -0,0 +1,20 @@ > > > +/* Test case for wmemcmp with race condition. > > > + Copyright (C) 2022 Free Software Foundation, Inc. > > > + This file is part of the GNU C Library. > > > + > > > + The GNU C Library is free software; you can redistribute it and/or > > > + modify it under the terms of the GNU Lesser General Public > > > + License as published by the Free Software Foundation; either > > > + version 2.1 of the License, or (at your option) any later version. > > > + > > > + The GNU C Library is distributed in the hope that it will be useful, > > > + but WITHOUT ANY WARRANTY; without even the implied warranty of > > > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > > + Lesser General Public License for more details. > > > + > > > + You should have received a copy of the GNU Lesser General Public > > > + License along with the GNU C Library; if not, see > > > + . */ > > > +#include > > > +#define WIDE 1 > > > +#include "tst-memcmp-race.c" > > > -- > > > 2.34.1 > > > > ping. ping2.