Messages in this thread Patch in this message | | | From | Petr Tesarik <> | Subject | [PATCH] Do not round per_cpu_ptr_to_phys to page boundary | Date | Fri, 16 Dec 2011 09:04:23 +0100 |
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The phys_addr_t per_cpu_ptr_to_phys() function ignores the offset within a page, whenever not using a simple translation using __pa().
Without this patch /sys/devices/system/cpu/cpu*/crash_notes shows incorrect values, which breaks kdump. Other things may also be broken.
Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
diff --git a/mm/percpu.c b/mm/percpu.c index 3bb810a..1a1b5ac 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -998,6 +998,7 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr) bool in_first_chunk = false; unsigned long first_low, first_high; unsigned int cpu; + phys_addr_t page_addr; /* * The following test on unit_low/high isn't strictly @@ -1023,9 +1024,10 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr) if (!is_vmalloc_addr(addr)) return __pa(addr); else - return page_to_phys(vmalloc_to_page(addr)); + page_addr = page_to_phys(vmalloc_to_page(addr)); } else - return page_to_phys(pcpu_addr_to_page(addr)); + page_addr = page_to_phys(pcpu_addr_to_page(addr)); + return page_addr + offset_in_page(addr); } /**
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