net: Use u64_stats_fetch_begin_irq() for stats fetch.
commit 278d3ba61563ceed3cb248383ced19e14ec7bc1f upstream. On 32bit-UP u64_stats_fetch_begin() disables only preemption. If the reader is in preemptible context and the writer side (u64_stats_update_begin*()) runs in an interrupt context (IRQ or softirq) then the writer can update the stats during the read operation. This update remains undetected. Use u64_stats_fetch_begin_irq() to ensure the stats fetch on 32bit-UP are not interrupted by a writer. 32bit-SMP remains unaffected by this change. Cc: "David S. Miller" <davem@davemloft.net> Cc: Catherine Sullivan <csully@google.com> Cc: David Awogbemila <awogbemila@google.com> Cc: Dimitris Michailidis <dmichail@fungible.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Jeroen de Borst <jeroendb@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Simon Horman <simon.horman@corigine.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-wireless@vger.kernel.org Cc: netdev@vger.kernel.org Cc: oss-drivers@corigine.com Cc: stable@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Greg Kroah-Hartman

parent
685f4e5671
commit
d71a1c9fce
@@ -67,10 +67,10 @@ nsim_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
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unsigned int start;
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do {
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start = u64_stats_fetch_begin(&ns->syncp);
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start = u64_stats_fetch_begin_irq(&ns->syncp);
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stats->tx_bytes = ns->tx_bytes;
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stats->tx_packets = ns->tx_packets;
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} while (u64_stats_fetch_retry(&ns->syncp, start));
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} while (u64_stats_fetch_retry_irq(&ns->syncp, start));
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}
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static int
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