Re: ubifs mount failure

[Sascha Hauer]

Hi,

On Tue, Dec 03, 2019 at 04:52:32AM +0000, Naga Sureshkumar Relli wrote:
>    Hi,
> 
>    Â
> 
>    We have upgraded our Linux kernel to 5.4 from 4.19.
> 
>    And I tried mounting ubifs using this kernel on NAND partition with below
>    command and saw that
> 
>    There is an issue with memory allocation.
> 
>    #mount -t ubifs ubi0:data /mnt/
> 
>    mount: mounting ubi0:data on /mnt/ failed: Cannot allocate memory
> 
>    Â
> 
>    I saw that there is a commit on fs/ubifs/sb.c, where it is allocating all
>    the required memories at one shot.
> 
>    [1]https://lkml.org/lkml/2018/9/7/724
> 
>    By reverting the above patch, I am able to mount successfully the ubifs.
> 
>    By reverting this patch, we are allocating, writing and freeing in a
>    manner such that, we donât see memory allocation issues.

Sorry, I can't see how this patch causes failing memory allocations. And
no, this is not expected. Could you sprinkle some printks and track down
where it fails? Is it the obvious place here:

	if (!sup || !mst || !idx || !ino || !cs) {
		err = -ENOMEM;
		goto out;
	}

If yes, which allocation fails and how much memory did we try to allocate?
If no, where does it fail? Also, where are you using UBIFS. Is it NAND flash
or NOR flash?

Sascha

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