On Thu, 2013-10-17 at 14:24 +0100, Will Deacon wrote: > During kernel stability testing on an SMP ARMv7 system, Yalin Wang > reported the following panic from the netfilter code: >
> On weakly ordered memory architectures, the writes to table->private > and newinfo->jumpstack from CPU1 can be observed out of order by CPU0. > Furthermore, on architectures which don't respect ordering of address > dependencies (i.e. Alpha), the reads from CPU0 can also be re-ordered. > > This patch adds an smp_wmb() before the assignment to table->private > (which is essentially publishing newinfo) to ensure that all writes to > newinfo will be observed before plugging it into the table structure. > A dependent-read barrier is also added on the consumer side, to ensure > the same ordering requirement are also respected there. > > Cc: Pablo Neira Ayuso <pa...@netfilter.org> > Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> > Reported-by: Wang, Yalin <yalin.w...@sonymobile.com> > Tested-by: Wang, Yalin <yalin.w...@sonymobile.com> > Signed-off-by: Will Deacon <will.dea...@arm.com> > --- Nice catch ! Acked-by: Eric Dumazet <eduma...@google.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
