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SubjectRe: [PATCH v2] MIPS: Kernel crashes on boot with SPARSEMEM + HIGHMEM enabled
On 03/31/2011 05:27 PM, Kevin Cernekee wrote:
> From: Michael Sundius<msundius@cisco.com>
>
> Fix 3 problems in the MIPS SPARSEMEM implementation:
>
> 1) mem_init() sets/clears PG_reserved on all pages in the HIGHMEM range
> without checking to see whether the page descriptor actually exists.
>
> 2) bootmem_init() never calls memory_present() on HIGHMEM pages, so
> page descriptors are never created for them if SPARSEMEM is enabled.
>
> 3) bootmem_init() calls memory_present() on lowmem pages before bootmem
> is fully set up. This is bad because memory_present() can allocate
> bootmem in some circumstances (e.g. if SPARSEMEM_EXTREME ever got
> enabled).
>


I think this may do the same thing as my patch:

http://patchwork.linux-mips.org/patch/1988/

Although my patch had different motivations, and changes some other
things around too.

David Daney


> Signed-off-by: Michael Sundius<msundius@cisco.com>
> Signed-off-by: Kevin Cernekee<cernekee@gmail.com>
> Cc: stable@kernel.org
> ---
> arch/mips/kernel/setup.c | 18 +++++++++++++++++-
> arch/mips/mm/init.c | 3 +++
> 2 files changed, 20 insertions(+), 1 deletions(-)
>
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index 8ad1d56..1f9f902 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -390,7 +390,6 @@ static void __init bootmem_init(void)
>
> /* Register lowmem ranges */
> free_bootmem(PFN_PHYS(start), size<< PAGE_SHIFT);
> - memory_present(0, start, end);
> }
>
> /*
> @@ -402,6 +401,23 @@ static void __init bootmem_init(void)
> * Reserve initrd memory if needed.
> */
> finalize_initrd();
> +
> + /*
> + * Call memory_present() on all valid ranges, for SPARSEMEM.
> + * This must be done after setting up bootmem, since memory_present()
> + * may allocate bootmem.
> + */
> + for (i = 0; i< boot_mem_map.nr_map; i++) {
> + unsigned long start, end;
> +
> + if (boot_mem_map.map[i].type != BOOT_MEM_RAM)
> + continue;
> +
> + start = PFN_UP(boot_mem_map.map[i].addr);
> + end = PFN_DOWN(boot_mem_map.map[i].addr
> + + boot_mem_map.map[i].size);
> + memory_present(0, start, end);
> + }
> }
>
> #endif /* CONFIG_SGI_IP27 */
> diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
> index 279599e..78a4cf2 100644
> --- a/arch/mips/mm/init.c
> +++ b/arch/mips/mm/init.c
> @@ -392,6 +392,9 @@ void __init mem_init(void)
> for (tmp = highstart_pfn; tmp< highend_pfn; tmp++) {
> struct page *page = pfn_to_page(tmp);
>
> + if (!pfn_valid(tmp))
> + continue;
> +
> if (!page_is_ram(tmp)) {
> SetPageReserved(page);
> continue;



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