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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2020-11-26 10:54:04 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2020-11-27 09:59:13 -0300
commitaa69f19a937b679816ef10e8620ea1141bb1734b (patch)
treefda886e3c6899912d8ebb5e65ace4710075bbc0f /nptl/pthread_cond_wait.c
parent71eeae0325a95f5e5d7ec4a27a6a6c357e0c8ef4 (diff)
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nptl: Add EOVERFLOW checks for futex calls
Some futex-internal calls require additional check for EOVERFLOW (as
indicated by [1] [2] [3]).  For both mutex and rwlock code, EOVERFLOW is
handle as ETIMEDOUT; since it indicate to the caller that the blocking
operation could not be issued.

For mutex it avoids a possible issue where PTHREAD_MUTEX_ROBUST_* might
assume EOVERFLOW indicate futex has succeed, and for PTHREAD_MUTEX_PP_*
it avoid a potential busy infinite loop.  For rwlock and semaphores, it
also avoids potential busy infinite loops.

Checked on x86_64-linux-gnu and i686-linux-gnu, although EOVERFLOW
won't be possible with current usage (since all timeouts on 32-bit
architectures with 32-bit time_t support will be in the range of
32-bit time_t).

[1] https://sourceware.org/pipermail/libc-alpha/2020-November/120079.html
[2] https://sourceware.org/pipermail/libc-alpha/2020-November/120080.html
[3] https://sourceware.org/pipermail/libc-alpha/2020-November/120127.html
Diffstat (limited to 'nptl/pthread_cond_wait.c')
-rw-r--r--nptl/pthread_cond_wait.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
index 685dbca32f..02d11c61db 100644
--- a/nptl/pthread_cond_wait.c
+++ b/nptl/pthread_cond_wait.c
@@ -506,7 +506,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
 
 	  __pthread_cleanup_pop (&buffer, 0);
 
-	  if (__glibc_unlikely (err == ETIMEDOUT))
+	  if (__glibc_unlikely (err == ETIMEDOUT || err == EOVERFLOW))
 	    {
 	      __condvar_dec_grefs (cond, g, private);
 	      /* If we timed out, we effectively cancel waiting.  Note that
@@ -515,7 +515,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
 		 __condvar_quiesce_and_switch_g1 and us trying to acquire
 		 the lock during cancellation is not possible.  */
 	      __condvar_cancel_waiting (cond, seq, g, private);
-	      result = ETIMEDOUT;
+	      result = err;
 	      goto done;
 	    }
 	  else