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authorDima Zavin <dima@android.com>2012-04-30 10:26:14 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-05-02 11:12:27 +0100
commit435a7ef52db7d86e67a009b36cac1457f8972391 (patch)
tree6d6bad75b3faf12e96e628e8ea90efa8c262bc1f /arch/arm/kernel/head.S
parent3e0f5a15f5003f4576c35498814f0f1567860449 (diff)
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ARM: 7409/1: Do not call flush_cache_user_range with mmap_sem held
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)] Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Dima Zavin <dima@android.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/head.S')
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