There are reports for hang in __check_pf:
https://github.com/JoeDog/siege/issues/4
It is reproducible only under specific configurations:
1. Large number of cores (>= 64) and large number of threads (> 3X of
the number of cores) with long lived socket connection.
2. Low power (frequency) mode.
3. Power management is enabled.
While holding lock, __check_pf calls make_request which calls __sendto
and __recvmsg. Since __sendto and __recvmsg are cancellation points,
lock held by __check_pf won't be released and can cause deadlock when
thread cancellation happens in __sendto or __recvmsg. Add a cancellation
cleanup handler for __check_pf to unlock the lock when cancelled by
another thread. This fixes BZ #20975 and the siege hang issue.
sysdep_routines += \
netlink_assert_response \
# sysdep_routines
+
+CFLAGS-check_pf.c += -fexceptions
endif
# Don't compile the ctype glue code, since there is no old non-GNU C library.
return NULL;
}
+#ifdef __EXCEPTIONS
+static void
+cancel_handler (void *arg __attribute__((unused)))
+{
+ /* Release the lock. */
+ __libc_lock_unlock (lock);
+}
+#endif
void
attribute_hidden
struct cached_data *olddata = NULL;
struct cached_data *data = NULL;
+#ifdef __EXCEPTIONS
+ /* Make sure that lock is released when the thread is cancelled. */
+ __libc_cleanup_push (cancel_handler, NULL);
+#endif
__libc_lock_lock (lock);
if (cache_valid_p ())
}
}
+#ifdef __EXCEPTIONS
+ __libc_cleanup_pop (0);
+#endif
__libc_lock_unlock (lock);
if (data != NULL)