Commit-ID: 60f583d56aa515b896a9d94f860f52640c1e8a75 Gitweb: http://git.kernel.org/tip/60f583d56aa515b896a9d94f860f52640c1e8a75 Author: Dave Hansen <dave@xxxxxxxx> AuthorDate: Thu, 7 Mar 2013 08:31:51 -0800 Committer: H. Peter Anvin <hpa@xxxxxxxxx> CommitDate: Thu, 7 Mar 2013 13:23:28 -0800 x86: Do not try to sync identity map for non-mapped pages kernel_map_sync_memtype() is called from a variety of contexts. The pat.c code that calls it seems to ensure that it is not called for non-ram areas by checking via pat_pagerange_is_ram(). It is important that it only be called on the actual identity map because there *IS* no map to sync for highmem pages, or for memory holes. The ioremap.c uses are not as careful as those from pat.c, and call kernel_map_sync_memtype() on PCI space which is in the middle of the kernel identity map _range_, but is not actually mapped. This patch adds a check to kernel_map_sync_memtype() which probably duplicates some of the checks already in pat.c. But, it is necessary for the ioremap.c uses and shouldn't hurt other callers. I have reproduced this bug and this patch fixes it for me and the original bug reporter: https://lkml.org/lkml/2013/2/5/396 Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20130307163151.D9B58C4E@xxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Dave Hansen <dave@xxxxxxxx> Tested-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx> --- arch/x86/mm/pat.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 2610bd9..6574388 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -563,6 +563,13 @@ int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags) if (base > __pa(high_memory-1)) return 0; + /* + * some areas in the middle of the kernel identity range + * are not mapped, like the PCI space. + */ + if (!page_is_ram(base >> PAGE_SHIFT)) + return 0; + id_sz = (__pa(high_memory-1) <= base + size) ? __pa(high_memory) - base : size; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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