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-rw-r--r--arch/arm/mm/alignment.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
index d073b64ae87..724ba3bce72 100644
--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c
@@ -885,8 +885,23 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
if (ai_usermode & UM_SIGNAL)
force_sig(SIGBUS, current);
- else
- set_cr(cr_no_alignment);
+ else {
+ /*
+ * We're about to disable the alignment trap and return to
+ * user space. But if an interrupt occurs before actually
+ * reaching user space, then the IRQ vector entry code will
+ * notice that we were still in kernel space and therefore
+ * the alignment trap won't be re-enabled in that case as it
+ * is presumed to be always on from kernel space.
+ * Let's prevent that race by disabling interrupts here (they
+ * are disabled on the way back to user space anyway in
+ * entry-common.S) and disable the alignment trap only if
+ * there is no work pending for this thread.
+ */
+ raw_local_irq_disable();
+ if (!(current_thread_info()->flags & _TIF_WORK_MASK))
+ set_cr(cr_no_alignment);
+ }
return 0;
}