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

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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 see 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/20210310004511.51996-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

(cherry picked from commit 9c08bd6a7410e916a8d38e932d913bb240219745
https: //git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm)
Link: https://lore.kernel.org/patchwork/patch/1392477/
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Bug: 160737021
Bug: 169683130
Change-Id: I09b7b75425115653ee6082e7f1846984fba197fe
This commit is contained in:
Peter Xu
2021-03-18 17:01:52 +11:00
committed by Todd Kjos
parent 1e1eb31e95
commit 56cfdd46b8
1 changed files with 0 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
tools/testing/selftests/vm/userfaultfd.c
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@@ -558,7 +558,6 @@ 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;
@@ -595,7 +594,6 @@ 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) {
@@ -658,12 +656,6 @@ 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;