* [LTP] [PATCH] syscall/fcntl33.c: fix test on FUSE fs
@ 2016-04-19 17:17 Alexey Kodanev
2016-04-19 18:01 ` Cyril Hrubis
0 siblings, 1 reply; 3+ messages in thread
From: Alexey Kodanev @ 2016-04-19 17:17 UTC (permalink / raw)
To: ltp
Even though a child process is waiting for a parent to be in 'S'
state before triggering SIGIO, the signal might come earlier than
sigtimedwait() being invoked in the parent process. As a result the
parent waited for the event that had already happened.
I can only think about that the parent process may be in a sleep state
somehow while executing open() syscall on which it might sleep while
running it on FUSE FS:
vfs -> fuse kernel driver -> userspace implementation.
It can be fixed if we move open() before fork.
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
---
testcases/kernel/syscalls/fcntl/fcntl33.c | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/testcases/kernel/syscalls/fcntl/fcntl33.c b/testcases/kernel/syscalls/fcntl/fcntl33.c
index 2d69866..13616c6 100644
--- a/testcases/kernel/syscalls/fcntl/fcntl33.c
+++ b/testcases/kernel/syscalls/fcntl/fcntl33.c
@@ -146,16 +146,17 @@ static void setup(void)
static void do_test(int i)
{
- pid_t cpid;
+ fd = SAFE_OPEN(cleanup, "file", O_RDONLY);
+
+ pid_t cpid = tst_fork();
- cpid = tst_fork();
if (cpid < 0)
tst_brkm(TBROK | TERRNO, cleanup, "fork() failed");
- if (cpid == 0)
+ if (cpid == 0) {
+ SAFE_CLOSE(NULL, fd);
do_child(i);
-
- fd = SAFE_OPEN(cleanup, "file", O_RDONLY);
+ }
TEST(fcntl(fd, F_SETLEASE, test_cases[i].lease_type));
if (TEST_RETURN == -1) {
--
1.7.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [LTP] [PATCH] syscall/fcntl33.c: fix test on FUSE fs
2016-04-19 17:17 [LTP] [PATCH] syscall/fcntl33.c: fix test on FUSE fs Alexey Kodanev
@ 2016-04-19 18:01 ` Cyril Hrubis
2016-04-20 10:55 ` Alexey Kodanev
0 siblings, 1 reply; 3+ messages in thread
From: Cyril Hrubis @ 2016-04-19 18:01 UTC (permalink / raw)
To: ltp
Hi!
> Even though a child process is waiting for a parent to be in 'S'
> state before triggering SIGIO, the signal might come earlier than
> sigtimedwait() being invoked in the parent process. As a result the
> parent waited for the event that had already happened.
>
> I can only think about that the parent process may be in a sleep state
> somehow while executing open() syscall on which it might sleep while
> running it on FUSE FS:
> vfs -> fuse kernel driver -> userspace implementation.
That sounds plausible to me. Depending on the actuall FUSE filesystem it
may do basically anything.
> It can be fixed if we move open() before fork.
>
> Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
> ---
> testcases/kernel/syscalls/fcntl/fcntl33.c | 11 ++++++-----
> 1 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/fcntl/fcntl33.c b/testcases/kernel/syscalls/fcntl/fcntl33.c
> index 2d69866..13616c6 100644
> --- a/testcases/kernel/syscalls/fcntl/fcntl33.c
> +++ b/testcases/kernel/syscalls/fcntl/fcntl33.c
> @@ -146,16 +146,17 @@ static void setup(void)
>
> static void do_test(int i)
> {
> - pid_t cpid;
> + fd = SAFE_OPEN(cleanup, "file", O_RDONLY);
> +
> + pid_t cpid = tst_fork();
>
> - cpid = tst_fork();
> if (cpid < 0)
> tst_brkm(TBROK | TERRNO, cleanup, "fork() failed");
>
> - if (cpid == 0)
> + if (cpid == 0) {
> + SAFE_CLOSE(NULL, fd);
> do_child(i);
> -
> - fd = SAFE_OPEN(cleanup, "file", O_RDONLY);
> + }
Looks good.
Another possible solution would be to use checkpoints and wait in the
child before we call tst_process_state_wait() and wake it up from parent
just before we call the fcntl(). But that would be more complicated than
this.
--
Cyril Hrubis
chrubis@suse.cz
^ permalink raw reply [flat|nested] 3+ messages in thread
* [LTP] [PATCH] syscall/fcntl33.c: fix test on FUSE fs
2016-04-19 18:01 ` Cyril Hrubis
@ 2016-04-20 10:55 ` Alexey Kodanev
0 siblings, 0 replies; 3+ messages in thread
From: Alexey Kodanev @ 2016-04-20 10:55 UTC (permalink / raw)
To: ltp
Hi,
On 19.04.2016 21:01, Cyril Hrubis wrote:
>
> static void do_test(int i)
> {
> - pid_t cpid;
> + fd = SAFE_OPEN(cleanup, "file", O_RDONLY);
> +
> + pid_t cpid = tst_fork();
>
> - cpid = tst_fork();
> if (cpid < 0)
> tst_brkm(TBROK | TERRNO, cleanup, "fork() failed");
>
> - if (cpid == 0)
> + if (cpid == 0) {
> + SAFE_CLOSE(NULL, fd);
> do_child(i);
> -
> - fd = SAFE_OPEN(cleanup, "file", O_RDONLY);
> + }
> Looks good.
>
> Another possible solution would be to use checkpoints and wait in the
> child before we call tst_process_state_wait() and wake it up from parent
> just before we call the fcntl(). But that would be more complicated than
> this.
Yes, it would be a more portable alternative instead of waiting for a
sleep state in a child.
Applied the original patch which has a simpler fix.
Thanks,
Alexey
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-04-19 17:17 [LTP] [PATCH] syscall/fcntl33.c: fix test on FUSE fs Alexey Kodanev
2016-04-19 18:01 ` Cyril Hrubis
2016-04-20 10:55 ` Alexey Kodanev
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