[v1,2/2] nptl: Add a testcase for inputs racey to {w}memcmp{eq} BZ #29863
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Commit Message
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 <goldstein.w.n@gmail.com>
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.
---
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
Comments
On Mon, Dec 19, 2022 at 11:27 AM Noah Goldstein <goldstein.w.n@gmail.com> 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 <goldstein.w.n@gmail.com>
> 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 <hjl.tools@gmail.com>",
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
> + <https://www.gnu.org/licenses/>. */
> +
> +/* 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 <stdio.h>
> +#include <stdint.h>
> +#include <string.h>
> +#include <string/test-string.h>
> +#include <support/xthread.h>
> +
> +#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 <support/test-driver.c>
> 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
> + <https://www.gnu.org/licenses/>. */
> +#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
> + <https://www.gnu.org/licenses/>. */
> +#include <wchar.h>
> +#define WIDE 1
> +#include "tst-memcmp-race.c"
> --
> 2.34.1
>
On Mon, Dec 19, 2022 at 11:28 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Mon, Dec 19, 2022 at 11:27 AM Noah Goldstein <goldstein.w.n@gmail.com> 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 <goldstein.w.n@gmail.com>
> > 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 <hjl.tools@gmail.com>",
> 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
> > + <https://www.gnu.org/licenses/>. */
> > +
> > +/* 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 <stdio.h>
> > +#include <stdint.h>
> > +#include <string.h>
> > +#include <string/test-string.h>
> > +#include <support/xthread.h>
> > +
> > +#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 <support/test-driver.c>
> > 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
> > + <https://www.gnu.org/licenses/>. */
> > +#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
> > + <https://www.gnu.org/licenses/>. */
> > +#include <wchar.h>
> > +#define WIDE 1
> > +#include "tst-memcmp-race.c"
> > --
> > 2.34.1
> >
ping.
On Thu, Dec 29, 2022 at 8:41 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Mon, Dec 19, 2022 at 11:28 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > On Mon, Dec 19, 2022 at 11:27 AM Noah Goldstein <goldstein.w.n@gmail.com> 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 <goldstein.w.n@gmail.com>
> > > 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 <hjl.tools@gmail.com>",
> > 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
> > > + <https://www.gnu.org/licenses/>. */
> > > +
> > > +/* 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 <stdio.h>
> > > +#include <stdint.h>
> > > +#include <string.h>
> > > +#include <string/test-string.h>
> > > +#include <support/xthread.h>
> > > +
> > > +#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 <support/test-driver.c>
> > > 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
> > > + <https://www.gnu.org/licenses/>. */
> > > +#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
> > > + <https://www.gnu.org/licenses/>. */
> > > +#include <wchar.h>
> > > +#define WIDE 1
> > > +#include "tst-memcmp-race.c"
> > > --
> > > 2.34.1
> > >
> ping.
ping2.
@@ -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 \
new file mode 100644
@@ -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
+ <https://www.gnu.org/licenses/>. */
+
+/* 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 <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <string/test-string.h>
+#include <support/xthread.h>
+
+#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 <support/test-driver.c>
new file mode 100644
@@ -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
+ <https://www.gnu.org/licenses/>. */
+#define TEST_MEMCMPEQ 1
+#include "tst-memcmp-race.c"
new file mode 100644
@@ -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
+ <https://www.gnu.org/licenses/>. */
+#include <wchar.h>
+#define WIDE 1
+#include "tst-memcmp-race.c"