Hello Stefan,

On Thu, Dec 01, 2011 at 05:10:23PM +0100, Stefan Hellermann wrote:

Am 01.12.2011 16:39, schrieb Uwe Kleine-K?nig:

quoted

The problem is that the memory for mem_map is allocated using:

	map = alloc_bootmem_node_nopanic(pgdat, size);

without any error checking. The _nopanic was introduced by commit

	8f389a99 (mm: use alloc_bootmem_node_nopanic() on really needed path)

I don't understand the commit's log and don't really see why it should
be allowed to not panic if the allocation failes here but use a NULL
pointer instead.
I put the people involved in 8f389a99 on Cc, maybe someone can comment?

Apart from that it seems I cannot use flatmem as is on my machine. It
has only 128kiB at 0x10000000 + 1MiB at 0x80000000 and needs 14MiB to hold the
table of "struct page"s. :-(

Best regards
Uwe

The commit was made after an bug report from me. I have an old x86
tablet pc with only 8Mb Ram. This machine fails early on bootup without
this commit. I found an archived message of the bug report here:
http://comments.gmane.org/gmane.linux.kernel/1135909

I saw that, too, but still I think that at least the last hunk in this
patch is wrong. (I didn't check the others.) For me the allocation for
mem_map failed and instead of handling the error somehow (be it a panic
or not) just using NULL isn't nice.

Best regards
Uwe

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