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authorEric Dumazet <edumazet@google.com>2016-05-03 16:56:03 -0700
committerDavid S. Miller <davem@davemloft.net>2016-05-04 16:55:11 -0400
commit46cc6e4976e3d9058490f20d93bc7805f7f2d81e (patch)
tree5856b8bab06927f7fc934b7f07a272f5ae680d9c /include/linux/u64_stats_sync.h
parent5332174a83720921a5ef6db8080a8691f7ccbc27 (diff)
tcp: fix lockdep splat in tcp_snd_una_update()
tcp_snd_una_update() and tcp_rcv_nxt_update() call u64_stats_update_begin() either from process context or BH handler. This triggers a lockdep splat on 32bit & SMP builds. We could add u64_stats_update_begin_bh() variant but this would slow down 32bit builds with useless local_disable_bh() and local_enable_bh() pairs, since we own the socket lock at this point. I add sock_owned_by_me() helper to have proper lockdep support even on 64bit builds, and new u64_stats_update_begin_raw() and u64_stats_update_end_raw methods. Fixes: c10d9310edf5 ("tcp: do not assume TCP code is non preemptible") Reported-by: Fabio Estevam <festevam@gmail.com> Diagnosed-by: Francois Romieu <romieu@fr.zoreil.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Tested-by: Fabio Estevam <fabio.estevam@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/u64_stats_sync.h')
-rw-r--r--include/linux/u64_stats_sync.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h
index df89c9bcba7d..d3a2bb712af3 100644
--- a/include/linux/u64_stats_sync.h
+++ b/include/linux/u64_stats_sync.h
@@ -89,6 +89,20 @@ static inline void u64_stats_update_end(struct u64_stats_sync *syncp)
#endif
}
+static inline void u64_stats_update_begin_raw(struct u64_stats_sync *syncp)
+{
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+ raw_write_seqcount_begin(&syncp->seq);
+#endif
+}
+
+static inline void u64_stats_update_end_raw(struct u64_stats_sync *syncp)
+{
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+ raw_write_seqcount_end(&syncp->seq);
+#endif
+}
+
static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *syncp)
{
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)