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Date: Sat, 13 Jan 2018 21:26:21 +0300
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Ingo Molnar <mingo@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>, x86@kernel.org,
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        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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        Vivek Goyal <vgoyal@redhat.com>, kexec@lists.infradead.org,
        stable@vger.kernel.org
Subject: Re: [PATCH] kdump: Write a correct address of mem_section into
 vmcoreinfo
Message-ID: <20180113182621.vypecadghlokdxta@node.shutemov.name>
References: <20180112162532.35896-1-kirill.shutemov@linux.intel.com>
 <20180113104838.ht57uooqk3fo546o@gmail.com>
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On Sat, Jan 13, 2018 at 11:48:38AM +0100, Ingo Molnar wrote:
> 
> * Kirill A. Shutemov <kirill.shutemov@linux.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@linux.intel.com>
> > Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
> > Cc: stable@vger.kernel.org
> > Acked-by: Baoquan He <bhe@redhat.com>
> > Acked-by: Dave Young <dyoung@redhat.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