linux-kernel - Re: [PATCH] kdump: Write a correct address of mem

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Message-ID: <20180113182621.vypecadghlokdxta@node.shutemov.name>
Date:   Sat, 13 Jan 2018 21:26:21 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Dave Young <dyoung@...hat.com>, Baoquan He <bhe@...hat.com>,
        Vivek Goyal <vgoyal@...hat.com>, kexec@...ts.infradead.org,
        stable@...r.kernel.org
Subject: Re: [PATCH] kdump: Write a correct address of mem_section into
 vmcoreinfo

On Sat, Jan 13, 2018 at 11:48:38AM +0100, Ingo Molnar wrote:
> 
> * Kirill A. Shutemov <kirill.shutemov@...ux.intel.com> wrote:
> 
> > Depending on configuration mem_section can now be an array or a pointer
> > to an array allocated dynamically. In most cases, we can continue to refer
> > to it as 'mem_section' regardless of what it is.
> > 
> > But there's one exception: '&mem_section' means "address of the array" if
> > mem_section is an array, but if mem_section is a pointer, it would mean
> > "address of the pointer".
> > 
> > We've stepped onto this in kdump code. VMCOREINFO_SYMBOL(mem_section)
> > writes down address of pointer into vmcoreinfo, not array as we wanted.
> > 
> > Let's introduce VMCOREINFO_SYMBOL_ARRAY() that would handle the
> > situation correctly for both cases.
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> > Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
> > Cc: stable@...r.kernel.org
> > Acked-by: Baoquan He <bhe@...hat.com>
> > Acked-by: Dave Young <dyoung@...hat.com>
> 
> You forgot the Reported-by - I added that to the commit.

Oops, sorry.

Note, that Andrew has already pick it up and sent it upstream.

-- 
 Kirill A. Shutemov