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Date:   Tue, 27 Jul 2021 09:38:17 +0200
From:   Michal Hocko <>
To:     "Matthew Wilcox (Oracle)" <>
Cc:     Al Viro <>,
        Qualys Security Advisory <>,
        Eric Sandeen <>,
        Linus Torvalds <>,,
Subject: Re: [PATCH] mm: Make kvmalloc refuse to allocate more than 2GB

On Wed 21-07-21 19:41:31, Matthew Wilcox wrote:
> It's generally dangerous to allocate such large quantities of memory
> within the kernel owing to our propensity to use 'int' to represent
> a length.  If somebody really needs it, we can add a kvmalloc_large()
> later, but let's default to "You can't allocate that much memory".

I do agree that limiting kvmalloc allocation size is a reasonable thing
to do but I do not really see why we should remove the check from
seq_buf_alloc. Implicitly relying on kvmalloc to workaround a bug that
was in seq_buf code seems like a step backwards to me.
Michal Hocko

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