| Message ID | 20210714180840.160798-1-amir73il@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | syscalls/fanotify: Fix running tests in a loop | expand |
Hi Amir, > Both fanotify19 and fanotify18 leaked fds when run in a loop. > fanotify19 was not checking child process exit status correctly > which resulted in random failures. Thanks for a quick fix! Reviewed-by: Petr Vorel <pvorel@suse.cz> FYI both fixes prolonged running for about 100% (comparing with runs on master which don't fail). Of course, that's not a problem at all, it's just interesting for me how simple closing of file descriptor can be expensive. Kind regards, Petr # time ./fanotify19 -i40 Summary: passed 360 failed 0 broken 0 skipped 0 warnings 0 real 0m0,871s user 0m0,028s sys 0m0,116s vs. Summary: passed 360 failed 0 broken 0 skipped 0 warnings 0 real 0m0,387s user 0m0,016s sys 0m0,122s # time ./fanotify19 -i10 Summary: passed 160 failed 0 broken 0 skipped 0 warnings 0 real 0m0,436s user 0m0,032s sys 0m0,128s vs. Summary: passed 160 failed 0 broken 0 skipped 0 warnings 0 real 0m0,876s user 0m0,052s sys 0m0,105s
On Thu, Jul 15, 2021 at 10:08 AM Petr Vorel <pvorel@suse.cz> wrote: > > Hi Amir, > > > Both fanotify19 and fanotify18 leaked fds when run in a loop. > > fanotify19 was not checking child process exit status correctly > > which resulted in random failures. > > Thanks for a quick fix! > Reviewed-by: Petr Vorel <pvorel@suse.cz> > > FYI both fixes prolonged running for about 100% (comparing with runs on master > which don't fail). Of course, that's not a problem at all, it's just interesting > for me how simple closing of file descriptor can be expensive. > Nice observation! LTP is not the only test suite that observed this issue. See: https://lore.kernel.org/linux-fsdevel/CAC-ggsFLmFpz5Y=-9MMLwxuO2LOS9rhpewDp_-u2hrT9J79ryg@mail.gmail.com/ In order to fix that issue we will need some LTP helpers to take care of closing fanotify/inotify fds in batches for loop runs, which is kind of what happened before the fd leak fix only the batch was infinite... Attached sample patch for fanotify18. You will need to run some more experiments to see if it is worth it or not and then if it is worth it, probably generalize the helpers. Thanks, Amir. > Kind regards, > Petr > > # time ./fanotify19 -i40 > > Summary: > passed 360 > failed 0 > broken 0 > skipped 0 > warnings 0 > > real 0m0,871s > user 0m0,028s > sys 0m0,116s > > vs. > > Summary: > passed 360 > failed 0 > broken 0 > skipped 0 > warnings 0 > > real 0m0,387s > user 0m0,016s > sys 0m0,122s > > # time ./fanotify19 -i10 > Summary: > passed 160 > failed 0 > broken 0 > skipped 0 > warnings 0 > > real 0m0,436s > user 0m0,032s > sys 0m0,128s > > vs. > > Summary: > passed 160 > failed 0 > broken 0 > skipped 0 > warnings 0 > > real 0m0,876s > user 0m0,052s > sys 0m0,105s
Hi Amir, ... > > FYI both fixes prolonged running for about 100% (comparing with runs on master > > which don't fail). Of course, that's not a problem at all, it's just interesting > > for me how simple closing of file descriptor can be expensive. > Nice observation! LTP is not the only test suite that observed this issue. See: > https://lore.kernel.org/linux-fsdevel/CAC-ggsFLmFpz5Y=-9MMLwxuO2LOS9rhpewDp_-u2hrT9J79ryg@mail.gmail.com/ > In order to fix that issue we will need some LTP helpers to take care of closing > fanotify/inotify fds in batches for loop runs, which is kind of what > happened before > the fd leak fix only the batch was infinite... > Attached sample patch for fanotify18. > You will need to run some more experiments to see if it is worth it or not > and then if it is worth it, probably generalize the helpers. Thanks for detailed info and patch. I'm going to merge the original patch as it's not an issue to run tests slower (more important is to actually fix the issue) and have look into your patchset whether it's worth of adding it. Kind regards, Petr
Hi Amir, merged, thanks! Kind regards, Petr
diff --git a/testcases/kernel/syscalls/fanotify/fanotify18.c b/testcases/kernel/syscalls/fanotify/fanotify18.c index 8a7eebba3..54a4b8ba0 100644 --- a/testcases/kernel/syscalls/fanotify/fanotify18.c +++ b/testcases/kernel/syscalls/fanotify/fanotify18.c @@ -136,7 +136,7 @@ static void test_fanotify(unsigned int n) (tc->mark_flags & DISALLOWED_MARK_FLAGS || tc->mark_mask & FAN_ALL_PERM_EVENTS)) { tst_res(TPASS, "Received result EPERM, as expected"); - return; + goto out; } tst_brk(TBROK | TERRNO, @@ -151,6 +151,9 @@ static void test_fanotify(unsigned int n) tst_res(TPASS, "fanotify_init() and fanotify_mark() returned successfully, " "as expected"); + +out: + SAFE_CLOSE(fd_notify); } static void setup(void) diff --git a/testcases/kernel/syscalls/fanotify/fanotify19.c b/testcases/kernel/syscalls/fanotify/fanotify19.c index 60714408d..fac257bb4 100644 --- a/testcases/kernel/syscalls/fanotify/fanotify19.c +++ b/testcases/kernel/syscalls/fanotify/fanotify19.c @@ -132,7 +132,7 @@ static void do_fork(void) SAFE_WAITPID(child, &status, 0); - if (WIFEXITED(child) && WEXITSTATUS(child) != 0) + if (WIFEXITED(status) && WEXITSTATUS(status) != 0) tst_brk(TBROK, "Child process terminated incorrectly. Aborting"); } @@ -255,6 +255,8 @@ static void test_fanotify(unsigned int n) event = FAN_EVENT_NEXT(event, len); } } + + SAFE_CLOSE(fd_notify); } static void setup(void)
Both fanotify19 and fanotify18 leaked fds when run in a loop. fanotify19 was not checking child process exit status correctly which resulted in random failures. Reported-by: Petr Vorel <pvorel@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> --- testcases/kernel/syscalls/fanotify/fanotify18.c | 5 ++++- testcases/kernel/syscalls/fanotify/fanotify19.c | 4 +++- 2 files changed, 7 insertions(+), 2 deletions(-)