[14/15] nptl: Use exit_lock when accessing TID on pthread_setschedprio

Message ID 20210930200051.1017457-15-adhemerval.zanella@linaro.org
State New
Headers show
Series
  • Fix various NPTL synchronization issues
Related show

Commit Message

Florian Weimer via Libc-alpha Sept. 30, 2021, 8 p.m.
Checked on x86_64-linux-gnu
---
 nptl/pthread_setschedprio.c          | 45 +++++++++++++++-------------
 sysdeps/pthread/tst-pthread-exited.c |  5 ++++
 2 files changed, 30 insertions(+), 20 deletions(-)

-- 
2.30.2

Patch

diff --git a/nptl/pthread_setschedprio.c b/nptl/pthread_setschedprio.c
index c095e346c8..65cf8912ca 100644
--- a/nptl/pthread_setschedprio.c
+++ b/nptl/pthread_setschedprio.c
@@ -15,25 +15,13 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <sched.h>
-#include <string.h>
-#include <sched.h>
-#include "pthreadP.h"
-#include <lowlevellock.h>
+#include <libc-lock.h>
+#include <pthreadP.h>
 #include <shlib-compat.h>
 
-int
-__pthread_setschedprio (pthread_t threadid, int prio)
+static int
+setschedprio (struct pthread *pd, int prio)
 {
-  struct pthread *pd = (struct pthread *) threadid;
-
-  /* Make sure the descriptor is valid.  */
-  if (INVALID_TD_P (pd))
-    /* Not a valid thread handle.  */
-    return ESRCH;
-
-  int result = 0;
   struct sched_param param;
   param.sched_priority = prio;
 
@@ -42,13 +30,12 @@  __pthread_setschedprio (pthread_t threadid, int prio)
 
   /* If the thread should have higher priority because of some
      PTHREAD_PRIO_PROTECT mutexes it holds, adjust the priority.  */
-  if (__builtin_expect (pd->tpp != NULL, 0) && pd->tpp->priomax > prio)
+  if (pd->tpp != NULL && pd->tpp->priomax > prio)
     param.sched_priority = pd->tpp->priomax;
 
   /* Try to set the scheduler information.  */
-  if (__glibc_unlikely (__sched_setparam (pd->tid, &param) == -1))
-    result = errno;
-  else
+  int r = INTERNAL_SYSCALL_CALL (sched_setparam, pd->tid, &param);
+  if (r == 0)
     {
       /* We succeeded changing the kernel information.  Reflect this
 	 change in the thread descriptor.  */
@@ -59,6 +46,24 @@  __pthread_setschedprio (pthread_t threadid, int prio)
 
   lll_unlock (pd->lock, LLL_PRIVATE);
 
+  return -r;
+}
+
+int
+__pthread_setschedprio (pthread_t threadid, int prio)
+{
+  struct pthread *pd = (struct pthread *) threadid;
+
+  /* Block all signals, as required by pd->exit_lock.  */
+  sigset_t old_mask;
+  __libc_signal_block_all (&old_mask);
+  __libc_lock_lock (pd->exit_lock);
+
+  int result = pd->tid != 0 ? setschedprio (pd, prio) : ESRCH;
+
+  __libc_lock_unlock (pd->exit_lock);
+  __libc_signal_restore_set (&old_mask);
+
   return result;
 }
 versioned_symbol (libc, __pthread_setschedprio, pthread_setschedprio,
diff --git a/sysdeps/pthread/tst-pthread-exited.c b/sysdeps/pthread/tst-pthread-exited.c
index bfb3870cb6..03cf2e21a1 100644
--- a/sysdeps/pthread/tst-pthread-exited.c
+++ b/sysdeps/pthread/tst-pthread-exited.c
@@ -88,6 +88,11 @@  do_test (void)
     TEST_COMPARE (r, ESRCH);
   }
 
+  {
+    int r = pthread_setschedprio (thr, 0);
+    TEST_COMPARE (r, ESRCH);
+  }
+
   xpthread_join (thr);
 
   return 0;