linux-kernel - Re: [LTP] [PATCH] ioctl_loop06: no validate block size

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Message-ID: <CAASaF6xh7_wXiFn9LakEv-LY-szkZ+5fJ0B67ygdCV0g4T-89Q@mail.gmail.com>
Date: Mon, 26 Aug 2024 15:15:06 +0200
From: Jan Stancek <jstancek@...hat.com>
To: Li Wang <liwang@...hat.com>
Cc: ltp@...ts.linux.it, John Garry <john.g.garry@...cle.com>, 
	Damien Le Moal <dlemoal@...nel.org>, "Michael S. Tsirkin" <mst@...hat.com>, 
	Stefan Hajnoczi <stefanha@...hat.com>, Jens Axboe <axboe@...nel.dk>, 
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [LTP] [PATCH] ioctl_loop06: no validate block size

On Mon, Aug 26, 2024 at 2:46 PM Li Wang <liwang@...hat.com> wrote:
>
> Hi All,
>
> On Mon, Aug 26, 2024 at 8:02 PM Li Wang <liwang@...hat.com> wrote:
>
> > Since commit 9423c653fe6110 ("loop: Don't bother validating blocksize")
> > kernel
> > drop validating blocksize for both loop_configure and loop_set_block_size
> > so
> > that set large block size succeeds.
> >
> > Error log:
> >   12 ioctl_loop06.c:76: TINFO: Using LOOP_SET_BLOCK_SIZE with arg >
> > PAGE_SIZE
> >   13 ioctl_loop06.c:59: TFAIL: Set block size succeed unexpectedly
> >   ...
> >   18 ioctl_loop06.c:76: TINFO: Using LOOP_CONFIGURE with block_size >
> > PAGE_SIZE
> >   19 ioctl_loop06.c:59:  TFAIL: Set block size succeed unexpectedly
> >
>
> Hmm, maybe I was wrong here, the commit says
>
>   "The block queue limits validation does this for us now."
>
> which indicates the validation is still on.
>
> So the test failure probably means a kernel bug but not a test problem.

Before the patch, blk_validate_block_size() did validate original
value as unsigned long,
after patch it's validated after cast to unsigned short.

In LTP thread you mentioned it failed on ppc64le/aarch64 and worked on
x86_64 and s390x.
Is it by chance now failing only on kernels with 64k page size?
(Test attempts to set block size to 2*page size.)

>
> CC block devs to give some advice.
>
>
>
> >
> > Signed-off-by: Li Wang <liwang@...hat.com>
> > ---
> >  testcases/kernel/syscalls/ioctl/ioctl_loop06.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/testcases/kernel/syscalls/ioctl/ioctl_loop06.c
> > b/testcases/kernel/syscalls/ioctl/ioctl_loop06.c
> > index 317f693a0..4aacd284a 100644
> > --- a/testcases/kernel/syscalls/ioctl/ioctl_loop06.c
> > +++ b/testcases/kernel/syscalls/ioctl/ioctl_loop06.c
> > @@ -23,6 +23,7 @@ static char dev_path[1024];
> >  static int dev_num, dev_fd, file_fd, attach_flag, loop_configure_sup = 1;
> >  static unsigned int invalid_value, half_value, unalign_value;
> >  static struct loop_config loopconfig;
> > +static int novalidate_blocksize = 0;
> >
> >  static struct tcase {
> >         unsigned int *setvalue;
> > @@ -74,6 +75,11 @@ static void run(unsigned int n)
> >         struct tcase *tc = &tcases[n];
> >
> >         tst_res(TINFO, "%s", tc->message);
> > +       if ((*(tc->setvalue) == invalid_value) && novalidate_blocksize) {
> > +               tst_res(TCONF, "Kernel doesn't validate block size, skip
> > invalid value test");
> > +               return;
> > +       }
> > +
> >         if (tc->ioctl_flag == LOOP_SET_BLOCK_SIZE) {
> >                 if (!attach_flag) {
> >                         tst_attach_device(dev_path, "test.img");
> > @@ -126,6 +132,9 @@ static void setup(void)
> >                 return;
> >         }
> >         loopconfig.fd = file_fd;
> > +
> > +       if ((tst_kvercmp(6, 11, 0)) >= 0)
> > +               novalidate_blocksize = 1;
> >  }
> >
> >  static void cleanup(void)
> > --
> > 2.46.0
> >
> >
> > --
> > Mailing list info: https://lists.linux.it/listinfo/ltp
> >
> >
>
> --
> Regards,
> Li Wang
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp