Commit ba4f8c35 authored by Peter Xu's avatar Peter Xu Committed by Linus Torvalds
Browse files

userfaultfd/selftests: remove the time() check on delayed uffd 

There seems to have no guarantee that time() will return the same for the
two calls even if there's no delay, e.g.  when a fault is accidentally
crossing the changing of a second.  Meanwhile, this message is also not
helping that much since delay could happen with a lot of reasons, e.g.,
schedule latency of resolving thread.  It may not mean an issue with uffd.

Neither do I saw this error triggered either in the past runs.  Even if it
triggers, it'll be drown in all the rest of test logs.  Remove it.

Link: https://lkml.kernel.org/r/20210412232753.1012412-3-peterx@redhat.com


Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Wang Qing <wangqing@vivo.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d2c6c06f

tools/testing/selftests/vm/userfaultfd.c

+0 −8
Original line number Diff line number Diff line
@@ -395,7 +395,6 @@ static void *locking_thread(void *arg) 
	unsigned long long count;

	char randstate[64];

	unsigned int seed;

	time_t start;



	if (bounces & BOUNCE_RANDOM) {

		seed = (unsigned int) time(NULL) - bounces;
@@ -432,7 +431,6 @@ static void *locking_thread(void *arg) 
			page_nr += 1;

		page_nr %= nr_pages;



		start = time(NULL);

		if (bounces & BOUNCE_VERIFY) {

			count = *area_count(area_dst, page_nr);

			if (!count) {
@@ -495,12 +493,6 @@ static void *locking_thread(void *arg) 
		count++;

		*area_count(area_dst, page_nr) = count_verify[page_nr] = count;

		pthread_mutex_unlock(area_mutex(area_dst, page_nr));



		if (time(NULL) - start > 1)

			fprintf(stderr,

				"userfault too slow %ld "

				"possible false positive with overcommit\n",

				time(NULL) - start);

	}



	return NULL;