Messages in this thread | | | Date | Thu, 17 Mar 2011 13:37:49 -0400 | Subject | Re: [PATCH v2] arm: cmpxchg syscall should data abort if page not write | From | Ashwin Chaugule <> |
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On Thu, Mar 17, 2011 at 1:01 PM, Nicolas Pitre <nicolas.pitre@linaro.org> wrote: > On Tue, 15 Mar 2011, Po-Yu Chuang wrote: > >> From: Po-Yu Chuang <ratbert@faraday-tech.com> >> >> If the page to cmpxchg is user mode read only (not write), >> we should simulate a data abort first. >> >> Signed-off-by: Po-Yu Chuang <ratbert@faraday-tech.com> > > Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org> > >> --- >> v2: >> remove !pte_young() check >> >> arch/arm/kernel/traps.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c >> index 446aee9..eac7c05 100644 >> --- a/arch/arm/kernel/traps.c >> +++ b/arch/arm/kernel/traps.c >> @@ -563,7 +563,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) >> if (!pmd_present(*pmd)) >> goto bad_access; >> pte = pte_offset_map_lock(mm, pmd, addr, &ptl); >> - if (!pte_present(*pte) || !pte_dirty(*pte)) { >> + if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) { >> pte_unmap_unlock(pte, ptl); >> goto bad_access; >> } >> -- >> 1.6.3.3 >>
Just beginning to understand the subtleties involved, so please correct me if I'm wrong. Wont this patch also fix the problem that was brought up with futexes on ARM SMP ?
http://lists.infradead.org/pipermail/linux-arm-kernel/2010-June/017374.html
Cheers, Ashwin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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