On Fri, 2012-05-25 at 15:38 +0100, Will Deacon wrote: > From: Dima Zavin <d...@android.com> > > commit 435a7ef52db7d86e67a009b36cac1457f8972391 upstream > > We can't be holding the mmap_sem while calling flush_cache_user_range > because the flush can fault. If we fault on a user address, the > page fault handler will try to take mmap_sem again. Since both places > acquire the read lock, most of the time it succeeds. However, if another > thread tries to acquire the write lock on the mmap_sem (e.g. mmap) in > between the call to flush_cache_user_range and the fault, the down_read > in do_page_fault will deadlock. > > [will: removed drop of vma parameter as already queued by rmk (7365/1)] > > Cc: <stable@vger.kernel.org> # 2.6.32+: 4542b6a0: ARM: 7365/1 > Cc: <stable@vger.kernel.org> # 2.6.32+ > Acked-by: Catalin Marinas <catalin.mari...@arm.com> > Signed-off-by: Dima Zavin <d...@android.com> > Signed-off-by: John Stultz <john.stu...@linaro.org> > Signed-off-by: Will Deacon <will.dea...@arm.com> > Signed-off-by: Russell King <rmk+ker...@arm.linux.org.uk> > --- > > Greg: This patch is a candidate for -stable, but its dependency (listed > above) wasn't marked as such, hence this retrospective submission. [...]
Both queued up for 3.2.y, thanks. Ben. -- Ben Hutchings You can't have everything. Where would you put it?
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