Hello Eli Billauer,
The patch 48bae0507410: "staging: New driver: Xillybus generic
interface for FPGA" from Jun 24, 2013, leads to the following static
checker warning:
drivers/char/xillybus/xillybus_core.c:941 xillybus_read()
error: double unlock 'mutex:&channel->wr_mutex'
drivers/char/xillybus/xillybus_core.c
904
905 if (mutex_lock_interruptible(
906 &channel->wr_mutex))
907 goto interrupted;
^^^^^^^^^^^^^^^^
We were interrupted before we could take the lock.
908 } while (channel->wr_sleepy);
909
910 continue;
911
912 interrupted: /* Mutex is not held if got here */
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Comment agrees.
913 if (channel->endpoint->fatal_error)
914 return -EIO;
915 if (bytes_done)
916 return bytes_done;
917 if (filp->f_flags & O_NONBLOCK)
918 return -EAGAIN; /* Don't admit snoozing */
919 return -EINTR;
920 }
921
922 left_to_sleep = deadline - ((long) jiffies);
923
924 /*
925 * If our time is out, skip the waiting. We may miss wr_sleepy
926 * being deasserted but hey, almost missing the train is like
927 * missing it.
928 */
929
930 if (left_to_sleep > 0) {
931 left_to_sleep =
932 wait_event_interruptible_timeout(
933 channel->wr_wait,
934 (!channel->wr_sleepy),
935 left_to_sleep);
936
937 if (left_to_sleep > 0) /* wr_sleepy deasserted */
938 continue;
939
940 if (left_to_sleep < 0) { /* Interrupt */
941 mutex_unlock(&channel->wr_mutex);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The static checker thinks we still don't have the lock sio it complains.
Possibly a false positive though because of the wait earlier?
942 if (channel->endpoint->fatal_error)
943 return -EIO;
944 if (bytes_done)
945 return bytes_done;
946 return -EINTR;
947 }
948 }
regards,
dan carpenter
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