| Message ID | 1462319763.5535.329.camel@edumazet-glaptop3.roam.corp.google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, May 3, 2016 at 8:56 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > From: Eric Dumazet <edumazet@google.com> > > 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> Thanks for the fix, Eric and Francois! This allows me to do NFS boot again: Tested-by: Fabio Estevam <fabio.estevam@nxp.com> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Tue, 03 May 2016 16:56:03 -0700 > From: Eric Dumazet <edumazet@google.com> > > 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> Applied. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h index df89c9bcba7db8dbde3bbf2b99f9af6ed562b112..d3a2bb712af3b9613b98ef9c3219f8dcd31568a5 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) diff --git a/include/net/sock.h b/include/net/sock.h index 45f5b492c65883cd22e2f615e019fe0d0ba31167..c9c8b19df27c558354687119db60c0716909ea3f 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1421,11 +1421,16 @@ static inline void unlock_sock_fast(struct sock *sk, bool slow) * accesses from user process context. */ -static inline bool sock_owned_by_user(const struct sock *sk) +static inline void sock_owned_by_me(const struct sock *sk) { #ifdef CONFIG_LOCKDEP WARN_ON_ONCE(!lockdep_sock_is_held(sk) && debug_locks); #endif +} + +static inline bool sock_owned_by_user(const struct sock *sk) +{ + sock_owned_by_me(sk); return sk->sk_lock.owned; } diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 6171f92be0903f5a5d17f027dbe6b31829bcc043..a914e0607895dd9321559f93c1008f8de13b73ad 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3355,9 +3355,10 @@ static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) { u32 delta = ack - tp->snd_una; - u64_stats_update_begin(&tp->syncp); + sock_owned_by_me((struct sock *)tp); + u64_stats_update_begin_raw(&tp->syncp); tp->bytes_acked += delta; - u64_stats_update_end(&tp->syncp); + u64_stats_update_end_raw(&tp->syncp); tp->snd_una = ack; } @@ -3366,9 +3367,10 @@ static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq) { u32 delta = seq - tp->rcv_nxt; - u64_stats_update_begin(&tp->syncp); + sock_owned_by_me((struct sock *)tp); + u64_stats_update_begin_raw(&tp->syncp); tp->bytes_received += delta; - u64_stats_update_end(&tp->syncp); + u64_stats_update_end_raw(&tp->syncp); tp->rcv_nxt = seq; }