locktorture: Print ratio of acquisitions, not failures

commit 80c503e0e68fbe271680ab48f0fe29bc034b01b7 upstream.

The __torture_print_stats() function in locktorture.c carefully
initializes local variable "min" to statp[0].n_lock_acquired, but
then compares it to statp[i].n_lock_fail.  Given that the .n_lock_fail
field should normally be zero, and given the initialization, it seems
reasonable to display the maximum and minimum number acquisitions
instead of miscomputing the maximum and minimum number of failures.
This commit therefore switches from failures to acquisitions.

And this turns out to be not only a day-zero bug, but entirely my
own fault.  I hate it when that happens!

Fixes: 0af3fe1efa53 ("locktorture: Add a lock-torture kernel module")
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 7d0b0ed744042d827886554951a24329879b93f0..95395ef5922ac9262211921507a00a452c332aaf 100644 (file)
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -710,10 +710,10 @@ static void __torture_print_stats(char *page,
                if (statp[i].n_lock_fail)
                        fail = true;
                sum += statp[i].n_lock_acquired;
-               if (max < statp[i].n_lock_fail)
-                       max = statp[i].n_lock_fail;
-               if (min > statp[i].n_lock_fail)
-                       min = statp[i].n_lock_fail;
+               if (max < statp[i].n_lock_acquired)
+                       max = statp[i].n_lock_acquired;
+               if (min > statp[i].n_lock_acquired)
+                       min = statp[i].n_lock_acquired;
        }
        page += sprintf(page,
                        "%s:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",