Commit-ID: f27d7759ad1ff48673831e598d6df4c76b2bcd06 Gitweb: http://git.kernel.org/tip/f27d7759ad1ff48673831e598d6df4c76b2bcd06 Author: H. Peter Anvin <[email protected]> AuthorDate: Thu, 13 Feb 2014 07:46:04 -0800 Committer: H. Peter Anvin <[email protected]> CommitDate: Thu, 13 Feb 2014 07:50:45 -0800
x86, smap: smap_violation() is bogus if CONFIG_X86_SMAP is off If CONFIG_X86_SMAP is disabled, smap_violation() tests for conditions which are incorrect (as the AC flag doesn't matter), causing spurious faults. The dynamic disabling of SMAP (nosmap on the command line) is fine because it disables X86_FEATURE_SMAP, therefore causing the static_cpu_has() to return false. Found by Fengguang Wu's test system. Reported-by: Fengguang Wu <[email protected]> Link: http://lkml.kernel.org/r/20140213124550.GA30497@localhost Signed-off-by: H. Peter Anvin <[email protected]> Cc: <[email protected]> # v3.7+ --- arch/x86/mm/fault.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 9d591c8..4b39bb7 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1087,12 +1087,14 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code) if (unlikely(error_code & PF_RSVD)) pgtable_bad(regs, error_code, address); +#ifdef CONFIG_X86_SMAP if (static_cpu_has(X86_FEATURE_SMAP)) { if (unlikely(smap_violation(error_code, regs))) { bad_area_nosemaphore(regs, error_code, address); return; } } +#endif /* * If we're in an interrupt, have no user context or are running -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
