Commit-ID: 7c59abb44f1f8b5637b775d14d01a223dc4f1a2d Gitweb: http://git.kernel.org/tip/7c59abb44f1f8b5637b775d14d01a223dc4f1a2d Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> AuthorDate: Fri, 19 Jun 2009 16:57:08 -0700 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Sat, 20 Jun 2009 15:23:45 +0200 perf_counter, x86: Improve interactions with fast-gup, clean up Remove the access_ok() logic from get_user_page_fast() and replace it with a check for canonical addresses. While the access_ok() check is correct too technically, it is wrong to make it more relaxed when KERNEL_DS is set. Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- arch/x86/mm/gup.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c index 2d1d784..71da1bc 100644 --- a/arch/x86/mm/gup.c +++ b/arch/x86/mm/gup.c @@ -303,11 +303,16 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write, start &= PAGE_MASK; addr = start; len = (unsigned long) nr_pages << PAGE_SHIFT; + end = start + len; - if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ, - (void __user *)start, len))) + if (end < start) goto slow_irqon; +#ifdef CONFIG_X86_64 + if (end >> __VIRTUAL_MASK_SHIFT) + goto slow_irqon; +#endif + /* * XXX: batch / limit 'nr', to avoid large irq off latency * needs some instrumenting to determine the common sizes used by -- 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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