Re: ubifs mount failure

[Richard Weinberger <richard.weinberger@xxxxxxxxx>]

On Tue, Dec 3, 2019 at 11:46 AM Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote:
>
> On Tue, Dec 03, 2019 at 04:06:12PM +0530, naga suresh kumar wrote:
> > Hi Richard,
> >
> > On Tue, Dec 3, 2019 at 2:40 PM Richard Weinberger <richard@xxxxxx> wrote:
> > >
> > > ----- Ursprüngliche Mail -----
> > > > Von: "Naga Sureshkumar Relli" <nagasure@xxxxxxxxxx>
> > > > https://elixir.bootlin.com/linux/v5.4/source/fs/ubifs/sb.c#L164
> > > > we are trying to allocate 4325376 (~4MB)
> > >
> > > 4MiB? Is ->min_io_size that large?
> > if you see https://elixir.bootlin.com/linux/latest/source/fs/ubifs/sb.c#L164
> > The size is actually ALIGN(tmp, c->min_io_size).
> > Here tmp is of 4325376 Bytes and min_io_size is 16384 Bytes
>
> 'tmp' contains bogus values. Try this:
>
> ----------------------------8<--------------------------------
>
> From 34f687fce189085f55706b4cddcb288a08f4ee06 Mon Sep 17 00:00:00 2001
> From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> Date: Tue, 3 Dec 2019 11:41:20 +0100
> Subject: [PATCH] ubifs: Fix wrong memory allocation
>
> In create_default_filesystem() when we allocate the idx node we must use
> the idx_node_size we calculated just one line before, not tmp, which
> contains completely other data.
>
> Fixes: c4de6d7e4319 ("ubifs: Refactor create_default_filesystem()")
> Reported-by: Naga Sureshkumar Relli <nagasure@xxxxxxxxxx>
> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> ---
>  fs/ubifs/sb.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
> index a551eb3e9b89..6681c18e52b8 100644
> --- a/fs/ubifs/sb.c
> +++ b/fs/ubifs/sb.c
> @@ -161,7 +161,7 @@ static int create_default_filesystem(struct ubifs_info *c)
>         sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL);
>         mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
>         idx_node_size = ubifs_idx_node_sz(c, 1);
> -       idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
> +       idx = kzalloc(ALIGN(idx_node_size, c->min_io_size), GFP_KERNEL);
>         ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL);
>         cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL);

Oh, looks good! Thanks for fixing, Sascha!

Thanks,
//richard

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