Re: [LTP] [PATCH 5/5] syscalls/fanotify10: Add test cases for evictable ignore mark

[Jan Stancek <jstancek@redhat.com>]

On Thu, Jun 30, 2022 at 10:21 AM Amir Goldstein <amir73il@gmail.com> wrote:
>
> On Thu, Jun 30, 2022 at 9:27 AM Jan Stancek <jstancek@redhat.com> wrote:
> >
> > On Mon, Jun 13, 2022 at 4:39 PM Amir Goldstein <amir73il@gmail.com> wrote:
> > >
> > > Test multiple groups with evictable mark with ignore mask
> > >
> > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > ---
> > >  .../kernel/syscalls/fanotify/fanotify10.c     | 78 +++++++++++++++++++
> > >  1 file changed, 78 insertions(+)
> > >
> > > diff --git a/testcases/kernel/syscalls/fanotify/fanotify10.c b/testcases/kernel/syscalls/fanotify/fanotify10.c
> > > index b9a50672d..52277d0b7 100644
> > > --- a/testcases/kernel/syscalls/fanotify/fanotify10.c
> > > +++ b/testcases/kernel/syscalls/fanotify/fanotify10.c
> > > @@ -71,6 +71,7 @@ static char event_buf[EVENT_BUF_LEN];
> > >  static int exec_events_unsupported;
> > >  static int fan_report_dfid_unsupported;
> > >  static int filesystem_mark_unsupported;
> > > +static int evictable_mark_unsupported;
> > >
> > >  #define MOUNT_PATH "fs_mnt"
> > >  #define MNT2_PATH "mntpoint"
> > > @@ -90,6 +91,10 @@ static int filesystem_mark_unsupported;
> > >  #define FILE_EXEC_PATH2 MNT2_PATH"/"TEST_APP
> > >  #define FILE2_EXEC_PATH2 MNT2_PATH"/"TEST_APP2
> > >
> > > +#define DROP_CACHES_FILE "/proc/sys/vm/drop_caches"
> > > +#define CACHE_PRESSURE_FILE "/proc/sys/vm/vfs_cache_pressure"
> > > +
> > > +static int old_cache_pressure;
> > >  static pid_t child_pid;
> > >  static int bind_mount_created;
> > >  static unsigned int num_classes = NUM_CLASSES;
> > > @@ -98,12 +103,14 @@ enum {
> > >         FANOTIFY_INODE,
> > >         FANOTIFY_MOUNT,
> > >         FANOTIFY_FILESYSTEM,
> > > +       FANOTIFY_EVICTABLE,
> > >  };
> > >
> > >  static struct fanotify_mark_type fanotify_mark_types[] = {
> > >         INIT_FANOTIFY_MARK_TYPE(INODE),
> > >         INIT_FANOTIFY_MARK_TYPE(MOUNT),
> > >         INIT_FANOTIFY_MARK_TYPE(FILESYSTEM),
> > > +       INIT_FANOTIFY_MARK_TYPE(EVICTABLE),
> > >  };
> > >
> > >  static struct tcase {
> > > @@ -289,14 +296,59 @@ static struct tcase {
> > >                 0,
> > >                 FILE_PATH, FAN_OPEN, FAN_OPEN
> > >         },
> > > +       /* Evictable ignore mark test cases */
> > > +       {
> > > +               "don't ignore mount events created on file with evicted ignore mark",
> > > +               MOUNT_PATH, FANOTIFY_MOUNT,
> > > +               FILE_PATH, FANOTIFY_EVICTABLE,
> > > +               0,
> > > +               FILE_PATH, FAN_OPEN, FAN_OPEN
> > > +       },
> > > +       {
> > > +               "don't ignore fs events created on a file with evicted ignore mark",
> > > +               MOUNT_PATH, FANOTIFY_FILESYSTEM,
> > > +               FILE_PATH, FANOTIFY_EVICTABLE,
> > > +               0,
> > > +               FILE_PATH, FAN_OPEN, FAN_OPEN
> > > +       },
> > > +       {
> > > +               "don't ignore mount events created inside a parent with evicted ignore mark",
> > > +               MOUNT_PATH, FANOTIFY_MOUNT,
> > > +               DIR_PATH, FANOTIFY_EVICTABLE,
> > > +               FAN_EVENT_ON_CHILD,
> > > +               FILE_PATH, FAN_OPEN, FAN_OPEN
> > > +       },
> > > +       {
> > > +               "don't ignore fs events created inside a parent with evicted ignore mark",
> > > +               MOUNT_PATH, FANOTIFY_FILESYSTEM,
> > > +               DIR_PATH, FANOTIFY_EVICTABLE,
> > > +               FAN_EVENT_ON_CHILD,
> > > +               FILE_PATH, FAN_OPEN, FAN_OPEN
> > > +       },
> >
> > Hi,
> >
> > we are seeing some sporadic failures from this last testcase, with
> > recent upstream kernels (v5.19-rc4-14-g941e3e791269).
> > Has anyone also ran into it and knows if it's bug on test side or kernel?
> >
> > fanotify10.c:496: TINFO: Test #27: don't ignore fs events created
> > inside a parent with evicted ignore mark
> > fanotify10.c:338: TPASS: No fanotify inode marks as expected
> > fanotify10.c:338: TPASS: No fanotify inode marks as expected
> > fanotify10.c:338: TPASS: No fanotify inode marks as expected
> > fanotify10.c:340: TFAIL: Unexpected inode mark (mflags=240,
> > mask=8000020 ignored_mask=20)
>
> It is a test bug.
> The problem is that we want to evict an inode, but there is no
> reliable mechanism to do that.
>
> This is the reason for this workaround in fanotify23:
>
>         /* Shrinkers on other fs do not work reliably enough to
> guarantee mark eviction on drop_caches */
>         .dev_fs_type = "ext2",
>
> I did not encounter the problem with fanotify10 myself, but it should
> be the same.
> fanotify10 is not filesystem dependent, so if you can apply the same workaround
> from fanotify23 and it works on your systems we can do that.

Test is using default fs type, which should already be ext2.
Here's a more complete log from failed test:
https://s3.us-east-1.amazonaws.com/arr-cki-prod-datawarehouse-public/datawarehouse-public/2022/06/30/redhat:576928171/build_ppc64le_redhat:576928171_ppc64le/tests/1/results_0001/job.01/recipes/12221009/tasks/8/logs/syscalls.fail.log


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