Commit 17de1e55 authored by Joel Savitz's avatar Joel Savitz Committed by Andrew Morton
Browse files

selftests: clarify common error when running gup_test 

The gup_test binary will fail showing only the output of perror("open") in
the case that /sys/kernel/debug/gup_test is not found. This will almost
always be due to CONFIG_GUP_TEST not being set, which enables
compilation of a kernel that provides this file.

Add a short error message to clarify this failure and point the user to
the solution.

Link: https://lkml.kernel.org/r/20220502224942.995427-1-jsavitz@redhat.com


Signed-off-by: default avatarJoel Savitz <jsavitz@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0768c8de

tools/testing/selftests/vm/gup_test.c

+2 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
#define FOLL_WRITE	0x01	/* check pte is writable */

#define FOLL_TOUCH	0x02	/* mark page accessed */



#define GUP_TEST_FILE "/sys/kernel/debug/gup_test"



static unsigned long cmd = GUP_FAST_BENCHMARK;

static int gup_fd, repeats = 1;

static unsigned long size = 128 * MB;