Messages in this thread Patch in this message | | | Date | Sun, 29 Jan 2006 21:04:44 +0100 | From | Eric Dumazet <> | Subject | [PATCH] i386: instead of poisoning .init zone, change protection bits to force a fault |
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Chasing some invalid accesses to .init zone, I found that free_init_pages() was properly freeing the pages but virtual was still usable.
A poisoning (memset(page, 0xcc, PAGE_SIZE)) was done but this is not reliable.
Applying this patch at least in mm is a good thing...
(After that we could map non possible cpu percpu data to the initial percpudata that is included in .init and discarded in free_initmem())
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
--- linux-2.6.16-rc1-mm3/arch/i386/mm/init.c 2006-01-25 10:17:24.000000000 +0100 +++ linux-2.6.16-rc1-mm3-ed/arch/i386/mm/init.c 2006-01-29 21:46:39.000000000 +0100 @@ -750,11 +750,12 @@ for (addr = begin; addr < end; addr += PAGE_SIZE) { ClearPageReserved(virt_to_page(addr)); set_page_count(virt_to_page(addr), 1); - memset((void *)addr, 0xcc, PAGE_SIZE); + change_page_attr(virt_to_page(addr), 1, __pgprot(0)); free_page(addr); totalram_pages++; } printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10); + global_flush_tlb(); } void free_initmem(void) | |