[PATCH v2] nptl: Fix __libc_cleanup_pop_restore asynchronous restore (BZ#29214)

[PATCH v2] nptl: Fix __libc_cleanup_pop_restore asynchronous restore (BZ#29214)

[Adhemerval Zanella]

This was due a wrong revert done on 404656009b459658.

Checked on x86_64-linux-gnu.
---
v2: Fixed sleep syscall handling.
---
 nptl/libc-cleanup.c            |  3 +-
 sysdeps/pthread/Makefile       |  1 +
 sysdeps/pthread/tst-cancel30.c | 82 ++++++++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/pthread/tst-cancel30.c

diff --git a/nptl/libc-cleanup.c b/nptl/libc-cleanup.c
index c4a83591bf..2ce59388d4 100644
--- a/nptl/libc-cleanup.c
+++ b/nptl/libc-cleanup.c
@@ -57,7 +57,8 @@ __libc_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer)
   THREAD_SETMEM (self, cleanup, buffer->__prev);
 
   int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
-  if (cancelhandling & CANCELTYPE_BITMASK)
+  if (buffer->__canceltype != PTHREAD_CANCEL_DEFERRED
+      && (cancelhandling & CANCELTYPE_BITMASK) == 0)
     {
       int newval;
       do
diff --git a/sysdeps/pthread/Makefile b/sysdeps/pthread/Makefile
index 8cebe7a784..7d1670da87 100644
--- a/sysdeps/pthread/Makefile
+++ b/sysdeps/pthread/Makefile
@@ -126,6 +126,7 @@ tests += tst-cnd-basic tst-mtx-trylock tst-cnd-broadcast \
 	 tst-pthread-raise-blocked-self \
 	 tst-pthread_kill-exited \
 	 tst-pthread_kill-exiting \
+	 tst-cancel30 \
 	 # tests
 
 tests-time64 += \
diff --git a/sysdeps/pthread/tst-cancel30.c b/sysdeps/pthread/tst-cancel30.c
new file mode 100644
index 0000000000..f7327c8786
--- /dev/null
+++ b/sysdeps/pthread/tst-cancel30.c
@@ -0,0 +1,82 @@
+/* Check if printf like functions does not disable asynchronous cancellation
+   mode (BZ#29214).
+
+   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 <support/check.h>
+#include <support/xstdio.h>
+#include <support/xthread.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+static pthread_barrier_t b;
+
+static void *
+tf (void *arg)
+{
+  int old;
+
+  TEST_COMPARE (pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, NULL), 0);
+
+  TEST_COMPARE (pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, &old), 0);
+  TEST_COMPARE (old, PTHREAD_CANCEL_ASYNCHRONOUS);
+
+  /* Check if internal lock cleanup routines restore the cancellation type
+     correctly.  */
+  printf ("...\n");
+  TEST_COMPARE (pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, &old), 0);
+  TEST_COMPARE (old, PTHREAD_CANCEL_ASYNCHRONOUS);
+
+  xpthread_barrier_wait (&b);
+
+  /* Wait indefinitely for cancellation, which only works if asynchronous
+     cancellation is enabled.  */
+#ifdef SYS_pause
+  syscall (__NR_pause);
+#elif defined SYS_ppoll || defined SYS_ppoll_time64
+# ifndef SYS_ppoll_time64
+#  define SYS_ppoll_time64 SYS_ppoll
+# endif
+  syscall (SYS_ppoll_time64, NULL, 0, NULL, NULL);
+#else
+  for (;;);
+#endif
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  xpthread_barrier_init (&b, NULL, 2);
+
+  pthread_t th = xpthread_create (NULL, tf, NULL);
+
+  xpthread_barrier_wait (&b);
+
+  xpthread_cancel (th);
+
+  void *status = xpthread_join (th);
+  TEST_VERIFY (status == PTHREAD_CANCELED);
+
+  return 0;
+}
+
+/* There is no need to wait full TIMEOUT if asynchronous is not working.  */
+#define TIMEOUT 3
+#include <support/test-driver.c>
-- 
2.34.1

Re: [PATCH v2] nptl: Fix __libc_cleanup_pop_restore asynchronous restore (BZ#29214)

[Andreas Schwab]

On Jun 07 2022, Adhemerval Zanella via Libc-alpha wrote:

> This was due a wrong revert done on 404656009b459658.

Ok.

> +  /* Wait indefinitely for cancellation, which only works if asynchronous
> +     cancellation is enabled.  */
> +#ifdef SYS_pause
> +  syscall (__NR_pause);

That should be SYS_pause.

-- 
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 v2] nptl: Fix __libc_cleanup_pop_restore asynchronous restore (BZ#29214)

[Adhemerval Zanella]

On 07/06/2022 12:48, Andreas Schwab wrote:
> On Jun 07 2022, Adhemerval Zanella via Libc-alpha wrote:
> 
>> This was due a wrong revert done on 404656009b459658.
> 
> Ok.
> 
>> +  /* Wait indefinitely for cancellation, which only works if asynchronous
>> +     cancellation is enabled.  */
>> +#ifdef SYS_pause
>> +  syscall (__NR_pause);
> 
> That should be SYS_pause.
> 

Ok, I will fix it.