[PATCH] debug: make __read_chk a cancellation point (bug 29274)

[PATCH] debug: make __read_chk a cancellation point (bug 29274)

[Andreas Schwab]

The __read_chk function, as the implementation behind the fortified read
function, must be a cancellation point, thus it cannot use INLINE_SYSCALL.
---
 debug/Makefile              |  7 ++++++
 debug/read_chk.c            | 10 --------
 debug/tst-read-chk-cancel.c | 50 +++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+), 10 deletions(-)
 create mode 100644 debug/tst-read-chk-cancel.c

diff --git a/debug/Makefile b/debug/Makefile
index 96029f32ee..456b349c4d 100644
--- a/debug/Makefile
+++ b/debug/Makefile
@@ -110,6 +110,7 @@ CPPFLAGS-tst-longjmp_chk2.c += -D_FORTIFY_SOURCE=1
 CFLAGS-tst-longjmp_chk3.c += -fexceptions -fasynchronous-unwind-tables
 CPPFLAGS-tst-longjmp_chk3.c += -D_FORTIFY_SOURCE=1
 CPPFLAGS-tst-realpath-chk.c += -D_FORTIFY_SOURCE=2
+CPPFLAGS-tst-read-chk-cancel.c += -D_FORTIFY_SOURCE=2
 
 # _FORTIFY_SOURCE tests.
 # Auto-generate tests for _FORTIFY_SOURCE for different levels, compilers and
@@ -204,6 +205,10 @@ ifeq ($(have-ssp),yes)
 tests += tst-ssp-1
 endif
 
+ifeq ($(have-thread-library), yes)
+tests += tst-read-chk-cancel
+endif
+
 ifeq (,$(CXX))
 tests-unsupported = $(tests-cc-chk)
 endif
@@ -242,3 +247,5 @@ $(objpfx)xtrace: xtrace.sh
 	    -e 's|@BINDIR@|$(bindir)|' -e 's|@PKGVERSION@|$(PKGVERSION)|' \
 	    -e 's|@REPORT_BUGS_TO@|$(REPORT_BUGS_TO)|' $^ > $@.new \
 	&& rm -f $@ && mv $@.new $@ && chmod +x $@
+
+$(objpfx)tst-read-chk-cancel: $(shared-thread-library)
diff --git a/debug/read_chk.c b/debug/read_chk.c
index 0cd58db8cb..274b4f93e9 100644
--- a/debug/read_chk.c
+++ b/debug/read_chk.c
@@ -16,12 +16,6 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <unistd.h>
-#include <sys/param.h>
-#ifdef HAVE_INLINED_SYSCALLS
-# include <errno.h>
-# include <sysdep.h>
-#endif
-
 
 ssize_t
 __read_chk (int fd, void *buf, size_t nbytes, size_t buflen)
@@ -29,9 +23,5 @@ __read_chk (int fd, void *buf, size_t nbytes, size_t buflen)
   if (nbytes > buflen)
     __chk_fail ();
 
-#ifdef HAVE_INLINED_SYSCALLS
-  return INLINE_SYSCALL (read, 3, fd, buf, nbytes);
-#else
   return __read (fd, buf, nbytes);
-#endif
 }
diff --git a/debug/tst-read-chk-cancel.c b/debug/tst-read-chk-cancel.c
new file mode 100644
index 0000000000..7e06afb596
--- /dev/null
+++ b/debug/tst-read-chk-cancel.c
@@ -0,0 +1,50 @@
+/* Test that __read_chk is a cancellation point (BZ #29274)
+   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 <stdint.h>
+#include <support/xunistd.h>
+#include <support/xthread.h>
+
+static int pipe_fds[2];
+static pthread_barrier_t barrier;
+
+static void *
+read_thread (void *n)
+{
+  xpthread_barrier_wait (&barrier);
+  char c;
+  /* This call should be forwarded to __read_chk because the buffer size
+     is known, but the read length is non-constant.  */
+  if (read (pipe_fds[0], &c, (uintptr_t) n) != 1)
+    return (void *) -1L;
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  xpthread_barrier_init (&barrier, 0, 2);
+  xpipe (pipe_fds);
+  pthread_t thr = xpthread_create (0, read_thread, (void *) 1L);
+  xpthread_barrier_wait (&barrier);
+  xpthread_cancel (thr);
+  xpthread_join (thr);
+  return 0;
+}
+
+#include <support/test-driver.c>
-- 
2.35.3


-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: [PATCH] debug: make __read_chk a cancellation point (bug 29274)

[Siddhesh Poyarekar]

On 22/06/2022 20:14, Andreas Schwab via Libc-alpha wrote:
> The __read_chk function, as the implementation behind the fortified read
> function, must be a cancellation point, thus it cannot use INLINE_SYSCALL.
> ---
>   debug/Makefile              |  7 ++++++
>   debug/read_chk.c            | 10 --------
>   debug/tst-read-chk-cancel.c | 50 +++++++++++++++++++++++++++++++++++++
>   3 files changed, 57 insertions(+), 10 deletions(-)
>   create mode 100644 debug/tst-read-chk-cancel.c

LGTM.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

> 
> diff --git a/debug/Makefile b/debug/Makefile
> index 96029f32ee..456b349c4d 100644
> --- a/debug/Makefile
> +++ b/debug/Makefile
> @@ -110,6 +110,7 @@ CPPFLAGS-tst-longjmp_chk2.c += -D_FORTIFY_SOURCE=1
>   CFLAGS-tst-longjmp_chk3.c += -fexceptions -fasynchronous-unwind-tables
>   CPPFLAGS-tst-longjmp_chk3.c += -D_FORTIFY_SOURCE=1
>   CPPFLAGS-tst-realpath-chk.c += -D_FORTIFY_SOURCE=2
> +CPPFLAGS-tst-read-chk-cancel.c += -D_FORTIFY_SOURCE=2
>   
>   # _FORTIFY_SOURCE tests.
>   # Auto-generate tests for _FORTIFY_SOURCE for different levels, compilers and
> @@ -204,6 +205,10 @@ ifeq ($(have-ssp),yes)
>   tests += tst-ssp-1
>   endif
>   
> +ifeq ($(have-thread-library), yes)
> +tests += tst-read-chk-cancel
> +endif
> +
>   ifeq (,$(CXX))
>   tests-unsupported = $(tests-cc-chk)
>   endif
> @@ -242,3 +247,5 @@ $(objpfx)xtrace: xtrace.sh
>   	    -e 's|@BINDIR@|$(bindir)|' -e 's|@PKGVERSION@|$(PKGVERSION)|' \
>   	    -e 's|@REPORT_BUGS_TO@|$(REPORT_BUGS_TO)|' $^ > $@.new \
>   	&& rm -f $@ && mv $@.new $@ && chmod +x $@
> +
> +$(objpfx)tst-read-chk-cancel: $(shared-thread-library)
> diff --git a/debug/read_chk.c b/debug/read_chk.c
> index 0cd58db8cb..274b4f93e9 100644
> --- a/debug/read_chk.c
> +++ b/debug/read_chk.c
> @@ -16,12 +16,6 @@
>      <https://www.gnu.org/licenses/>.  */
>   
>   #include <unistd.h>
> -#include <sys/param.h>
> -#ifdef HAVE_INLINED_SYSCALLS
> -# include <errno.h>
> -# include <sysdep.h>
> -#endif
> -
>   
>   ssize_t
>   __read_chk (int fd, void *buf, size_t nbytes, size_t buflen)
> @@ -29,9 +23,5 @@ __read_chk (int fd, void *buf, size_t nbytes, size_t buflen)
>     if (nbytes > buflen)
>       __chk_fail ();
>   
> -#ifdef HAVE_INLINED_SYSCALLS
> -  return INLINE_SYSCALL (read, 3, fd, buf, nbytes);
> -#else
>     return __read (fd, buf, nbytes);
> -#endif
>   }
> diff --git a/debug/tst-read-chk-cancel.c b/debug/tst-read-chk-cancel.c
> new file mode 100644
> index 0000000000..7e06afb596
> --- /dev/null
> +++ b/debug/tst-read-chk-cancel.c
> @@ -0,0 +1,50 @@
> +/* Test that __read_chk is a cancellation point (BZ #29274)
> +   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 <stdint.h>
> +#include <support/xunistd.h>
> +#include <support/xthread.h>
> +
> +static int pipe_fds[2];
> +static pthread_barrier_t barrier;
> +
> +static void *
> +read_thread (void *n)
> +{
> +  xpthread_barrier_wait (&barrier);
> +  char c;
> +  /* This call should be forwarded to __read_chk because the buffer size
> +     is known, but the read length is non-constant.  */
> +  if (read (pipe_fds[0], &c, (uintptr_t) n) != 1)
> +    return (void *) -1L;
> +  return 0;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  xpthread_barrier_init (&barrier, 0, 2);
> +  xpipe (pipe_fds);
> +  pthread_t thr = xpthread_create (0, read_thread, (void *) 1L);
> +  xpthread_barrier_wait (&barrier);
> +  xpthread_cancel (thr);
> +  xpthread_join (thr);
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>

Re: [PATCH] debug: make __read_chk a cancellation point (bug 29274)

[Adhemerval Zanella]

> On 22 Jun 2022, at 11:44, Andreas Schwab via Libc-alpha <libc-alpha@sourceware.org> wrote:
> 
> The __read_chk function, as the implementation behind the fortified read
> function, must be a cancellation point, thus it cannot use INLINE_SYSCALL.
> ---
> debug/Makefile              |  7 ++++++
> debug/read_chk.c            | 10 --------
> debug/tst-read-chk-cancel.c | 50 +++++++++++++++++++++++++++++++++++++

Maybe add a tst-cancel4-chk that builds with _FORTIFY_SOURCE=2 so we can tests
more cancellation entrypoints?

[PATCH] debug: test for more required cacellation points (bug 29274)

[Andreas Schwab]

Generalize the test for cancellation point in __read_chk to also test the
other fortified functions with required cancellation points.
---
 debug/Makefile              |   6 +-
 debug/tst-chk-cancel.c      | 108 ++++++++++++++++++++++++++++++++++++
 debug/tst-read-chk-cancel.c |  50 -----------------
 3 files changed, 111 insertions(+), 53 deletions(-)
 create mode 100644 debug/tst-chk-cancel.c
 delete mode 100644 debug/tst-read-chk-cancel.c

diff --git a/debug/Makefile b/debug/Makefile
index 456b349c4d..99cdf3221b 100644
--- a/debug/Makefile
+++ b/debug/Makefile
@@ -110,7 +110,7 @@ CPPFLAGS-tst-longjmp_chk2.c += -D_FORTIFY_SOURCE=1
 CFLAGS-tst-longjmp_chk3.c += -fexceptions -fasynchronous-unwind-tables
 CPPFLAGS-tst-longjmp_chk3.c += -D_FORTIFY_SOURCE=1
 CPPFLAGS-tst-realpath-chk.c += -D_FORTIFY_SOURCE=2
-CPPFLAGS-tst-read-chk-cancel.c += -D_FORTIFY_SOURCE=2
+CPPFLAGS-tst-chk-cancel.c += -D_FORTIFY_SOURCE=2
 
 # _FORTIFY_SOURCE tests.
 # Auto-generate tests for _FORTIFY_SOURCE for different levels, compilers and
@@ -206,7 +206,7 @@ tests += tst-ssp-1
 endif
 
 ifeq ($(have-thread-library), yes)
-tests += tst-read-chk-cancel
+tests += tst-chk-cancel
 endif
 
 ifeq (,$(CXX))
@@ -248,4 +248,4 @@ $(objpfx)xtrace: xtrace.sh
 	    -e 's|@REPORT_BUGS_TO@|$(REPORT_BUGS_TO)|' $^ > $@.new \
 	&& rm -f $@ && mv $@.new $@ && chmod +x $@
 
-$(objpfx)tst-read-chk-cancel: $(shared-thread-library)
+$(objpfx)tst-chk-cancel: $(shared-thread-library)
diff --git a/debug/tst-chk-cancel.c b/debug/tst-chk-cancel.c
new file mode 100644
index 0000000000..dec85ef067
--- /dev/null
+++ b/debug/tst-chk-cancel.c
@@ -0,0 +1,108 @@
+/* Test for required cancellation points in fortified functions (BZ #29274)
+   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 <stdint.h>
+#include <poll.h>
+#include <support/xunistd.h>
+#include <support/xthread.h>
+
+static int pipe_fds[2];
+static pthread_barrier_t barrier;
+
+static void *
+read_thread (void *n)
+{
+  xpthread_barrier_wait (&barrier);
+  char c;
+  /* This call should be forwarded to __read_chk because the buffer size
+     is known, but the read length is non-constant.  */
+  if (read (pipe_fds[0], &c, (uintptr_t) n) != 1)
+    return (void *) -1L;
+  return 0;
+}
+
+static void *
+pread_thread (void *n)
+{
+  xpthread_barrier_wait (&barrier);
+  char c;
+  /* This call should be forwarded to __pread_chk because the buffer size
+     is known, but the read length is non-constant.  */
+  if (pread (pipe_fds[0], &c, (uintptr_t) n, 0) != 1)
+    return (void *) -1L;
+  return 0;
+}
+
+static void *
+pread64_thread (void *n)
+{
+  xpthread_barrier_wait (&barrier);
+  char c;
+  /* This call should be forwarded to __pread64_chk because the buffer size
+     is known, but the read length is non-constant.  */
+  if (pread64 (pipe_fds[0], &c, (uintptr_t) n, 0) != 1)
+    return (void *) -1L;
+  return 0;
+}
+
+static void *
+poll_thread (void *n)
+{
+  xpthread_barrier_wait (&barrier);
+  struct pollfd pfd = { pipe_fds[0], POLLIN, 0 };
+  /* This call should be forwarded to __poll_chk because the pollfd size
+     is known, but the number of entries is non-constant.  */
+  if (poll (&pfd, (uintptr_t) n, -1) != 1)
+    return (void *) -1L;
+  return 0;
+}
+
+static void *
+ppoll_thread (void *n)
+{
+  xpthread_barrier_wait (&barrier);
+  struct pollfd pfd = { pipe_fds[0], POLLIN, 0 };
+  /* This call should be forwarded to __ppoll_chk because the pollfd size
+     is known, but the number of entries is non-constant.  */
+  if (ppoll (&pfd, (uintptr_t) n, 0, 0) != 1)
+    return (void *) -1L;
+  return 0;
+}
+
+static void *(*thread_fct[]) (void *) =
+  {
+    read_thread, pread_thread, pread64_thread, poll_thread, ppoll_thread
+  };
+  
+static int
+do_test (void)
+{
+  xpthread_barrier_init (&barrier, 0, 2);
+  xpipe (pipe_fds);
+  for (int i = 0; i < sizeof (thread_fct) / sizeof (thread_fct[0]); i++)
+    {
+      pthread_t thr = xpthread_create (0, thread_fct[i], (void *) 1L);
+      xpthread_barrier_wait (&barrier);
+      xpthread_cancel (thr);
+      xpthread_join (thr);
+    }
+  xpthread_barrier_destroy (&barrier);
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/debug/tst-read-chk-cancel.c b/debug/tst-read-chk-cancel.c
deleted file mode 100644
index 7e06afb596..0000000000
--- a/debug/tst-read-chk-cancel.c
+++ /dev/null
@@ -1,50 +0,0 @@
-/* Test that __read_chk is a cancellation point (BZ #29274)
-   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 <stdint.h>
-#include <support/xunistd.h>
-#include <support/xthread.h>
-
-static int pipe_fds[2];
-static pthread_barrier_t barrier;
-
-static void *
-read_thread (void *n)
-{
-  xpthread_barrier_wait (&barrier);
-  char c;
-  /* This call should be forwarded to __read_chk because the buffer size
-     is known, but the read length is non-constant.  */
-  if (read (pipe_fds[0], &c, (uintptr_t) n) != 1)
-    return (void *) -1L;
-  return 0;
-}
-
-static int
-do_test (void)
-{
-  xpthread_barrier_init (&barrier, 0, 2);
-  xpipe (pipe_fds);
-  pthread_t thr = xpthread_create (0, read_thread, (void *) 1L);
-  xpthread_barrier_wait (&barrier);
-  xpthread_cancel (thr);
-  xpthread_join (thr);
-  return 0;
-}
-
-#include <support/test-driver.c>
-- 
2.35.3


-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: [PATCH] debug: test for more required cacellation points (bug 29274)

[Adhemerval Zanella]

> On 23 Jun 2022, at 06:00, Andreas Schwab <schwab@suse.de> wrote:
> 
> Generalize the test for cancellation point in __read_chk to also test the
> other fortified functions with required cancellation points.

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> ---
> debug/Makefile              |   6 +-
> debug/tst-chk-cancel.c      | 108 ++++++++++++++++++++++++++++++++++++
> debug/tst-read-chk-cancel.c |  50 -----------------
> 3 files changed, 111 insertions(+), 53 deletions(-)
> create mode 100644 debug/tst-chk-cancel.c
> delete mode 100644 debug/tst-read-chk-cancel.c
> 
> diff --git a/debug/Makefile b/debug/Makefile
> index 456b349c4d..99cdf3221b 100644
> --- a/debug/Makefile
> +++ b/debug/Makefile
> @@ -110,7 +110,7 @@ CPPFLAGS-tst-longjmp_chk2.c += -D_FORTIFY_SOURCE=1
> CFLAGS-tst-longjmp_chk3.c += -fexceptions -fasynchronous-unwind-tables
> CPPFLAGS-tst-longjmp_chk3.c += -D_FORTIFY_SOURCE=1
> CPPFLAGS-tst-realpath-chk.c += -D_FORTIFY_SOURCE=2
> -CPPFLAGS-tst-read-chk-cancel.c += -D_FORTIFY_SOURCE=2
> +CPPFLAGS-tst-chk-cancel.c += -D_FORTIFY_SOURCE=2
> 
> # _FORTIFY_SOURCE tests.
> # Auto-generate tests for _FORTIFY_SOURCE for different levels, compilers and
> @@ -206,7 +206,7 @@ tests += tst-ssp-1
> endif
> 
> ifeq ($(have-thread-library), yes)
> -tests += tst-read-chk-cancel
> +tests += tst-chk-cancel
> endif
> 
> ifeq (,$(CXX))
> @@ -248,4 +248,4 @@ $(objpfx)xtrace: xtrace.sh
> 	    -e 's|@REPORT_BUGS_TO@|$(REPORT_BUGS_TO)|' $^ > $@.new \
> 	&& rm -f $@ && mv $@.new $@ && chmod +x $@
> 
> -$(objpfx)tst-read-chk-cancel: $(shared-thread-library)
> +$(objpfx)tst-chk-cancel: $(shared-thread-library)

Ok.

> diff --git a/debug/tst-chk-cancel.c b/debug/tst-chk-cancel.c
> new file mode 100644
> index 0000000000..dec85ef067
> --- /dev/null
> +++ b/debug/tst-chk-cancel.c
> @@ -0,0 +1,108 @@
> +/* Test for required cancellation points in fortified functions (BZ #29274)
> +   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 <stdint.h>
> +#include <poll.h>
> +#include <support/xunistd.h>
> +#include <support/xthread.h>
> +
> +static int pipe_fds[2];
> +static pthread_barrier_t barrier;
> +
> +static void *
> +read_thread (void *n)
> +{
> +  xpthread_barrier_wait (&barrier);
> +  char c;
> +  /* This call should be forwarded to __read_chk because the buffer size
> +     is known, but the read length is non-constant.  */
> +  if (read (pipe_fds[0], &c, (uintptr_t) n) != 1)
> +    return (void *) -1L;
> +  return 0;
> +}
> +
> +static void *
> +pread_thread (void *n)
> +{
> +  xpthread_barrier_wait (&barrier);
> +  char c;
> +  /* This call should be forwarded to __pread_chk because the buffer size
> +     is known, but the read length is non-constant.  */
> +  if (pread (pipe_fds[0], &c, (uintptr_t) n, 0) != 1)
> +    return (void *) -1L;
> +  return 0;
> +}
> +
> +static void *
> +pread64_thread (void *n)
> +{
> +  xpthread_barrier_wait (&barrier);
> +  char c;
> +  /* This call should be forwarded to __pread64_chk because the buffer size
> +     is known, but the read length is non-constant.  */
> +  if (pread64 (pipe_fds[0], &c, (uintptr_t) n, 0) != 1)
> +    return (void *) -1L;
> +  return 0;
> +}
> +
> +static void *
> +poll_thread (void *n)
> +{
> +  xpthread_barrier_wait (&barrier);
> +  struct pollfd pfd = { pipe_fds[0], POLLIN, 0 };
> +  /* This call should be forwarded to __poll_chk because the pollfd size
> +     is known, but the number of entries is non-constant.  */
> +  if (poll (&pfd, (uintptr_t) n, -1) != 1)
> +    return (void *) -1L;
> +  return 0;
> +}
> +
> +static void *
> +ppoll_thread (void *n)
> +{
> +  xpthread_barrier_wait (&barrier);
> +  struct pollfd pfd = { pipe_fds[0], POLLIN, 0 };
> +  /* This call should be forwarded to __ppoll_chk because the pollfd size
> +     is known, but the number of entries is non-constant.  */
> +  if (ppoll (&pfd, (uintptr_t) n, 0, 0) != 1)
> +    return (void *) -1L;
> +  return 0;
> +}
> +
> +static void *(*thread_fct[]) (void *) =
> +  {
> +    read_thread, pread_thread, pread64_thread, poll_thread, ppoll_thread
> +  };
> +  
> +static int
> +do_test (void)
> +{
> +  xpthread_barrier_init (&barrier, 0, 2);
> +  xpipe (pipe_fds);
> +  for (int i = 0; i < sizeof (thread_fct) / sizeof (thread_fct[0]); i++)
> +    {
> +      pthread_t thr = xpthread_create (0, thread_fct[i], (void *) 1L);
> +      xpthread_barrier_wait (&barrier);
> +      xpthread_cancel (thr);
> +      xpthread_join (thr);
> +    }
> +  xpthread_barrier_destroy (&barrier);
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>

Ok.

> diff --git a/debug/tst-read-chk-cancel.c b/debug/tst-read-chk-cancel.c
> deleted file mode 100644
> index 7e06afb596..0000000000
> --- a/debug/tst-read-chk-cancel.c
> +++ /dev/null
> @@ -1,50 +0,0 @@
> -/* Test that __read_chk is a cancellation point (BZ #29274)
> -   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 <stdint.h>
> -#include <support/xunistd.h>
> -#include <support/xthread.h>
> -
> -static int pipe_fds[2];
> -static pthread_barrier_t barrier;
> -
> -static void *
> -read_thread (void *n)
> -{
> -  xpthread_barrier_wait (&barrier);
> -  char c;
> -  /* This call should be forwarded to __read_chk because the buffer size
> -     is known, but the read length is non-constant.  */
> -  if (read (pipe_fds[0], &c, (uintptr_t) n) != 1)
> -    return (void *) -1L;
> -  return 0;
> -}
> -
> -static int
> -do_test (void)
> -{
> -  xpthread_barrier_init (&barrier, 0, 2);
> -  xpipe (pipe_fds);
> -  pthread_t thr = xpthread_create (0, read_thread, (void *) 1L);
> -  xpthread_barrier_wait (&barrier);
> -  xpthread_cancel (thr);
> -  xpthread_join (thr);
> -  return 0;
> -}
> -
> -#include <support/test-driver.c>
> -- 
> 2.35.3
> 

Ok.

> 
> -- 
> Andreas Schwab, SUSE Labs, schwab@suse.de
> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
> "And now for something completely different."

Re: [PATCH] debug: test for more required cacellation points (bug 29274)

[Andreas Schwab]

It doesn't work.  pread absolutely requires a seekable file, but I don't
know how to create a seekable *and* blocking file.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: [PATCH] debug: test for more required cacellation points (bug 29274)

[Florian Weimer]

* Andreas Schwab via Libc-alpha:

> It doesn't work.  pread absolutely requires a seekable file, but I don't
> know how to create a seekable *and* blocking file.

It should be possible to achieve that using FUSE.

Thanks,
Florian

Re: [PATCH] debug: test for more required cacellation points (bug 29274)

[Adhemerval Zanella]

> On 23 Jun 2022, at 11:13, Andreas Schwab <schwab@suse.de> wrote:
> 
> It doesn't work.  pread absolutely requires a seekable file, but I don't
> know how to create a seekable *and* blocking file.

sysdeps/pthread/tst-cancel4.c check if pread works with a pending
cancelation.  Maybe add the same strategy on this new test.

> 
> -- 
> Andreas Schwab, SUSE Labs, schwab@suse.de
> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
> "And now for something completely different."