From patchwork Fri Oct 6 15:49:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13411715 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 61D45250EA; Fri, 6 Oct 2023 15:49:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="HjJJuLvB"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="o2Ywy+Xx" Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 514F59E; Fri, 6 Oct 2023 08:49:37 -0700 (PDT) Date: Fri, 6 Oct 2023 17:49:33 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1696607375; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9q17Rnwalf8d2r5qhJCl4UbgZm/wHnyRkams51NJ4NA=; b=HjJJuLvBW4NjHffGM2tQbwZPggXBlC4NfRrzhBjOS6BDqqDHsxc4uLUkb7PE8mdx/kjXg/ GFwhJlR1yxb7o9DS2OLpM4POchai9snnwERphxaNPXclmfVy5niudTtbVdH+qtaojke/NJ Woa310BRs/lFN3B12sfIiZdMArVp4M9F1UoBL4FaA4bMJ/xnlotHHmCRMVX++y4hPSqfT3 YZE2IL0g7BBf27yNC3J5FqaJGdY+6aUYZlM6gioyhohpBxEqUskTBdd0jX3VCu2G5YNQQl 1mmkCtA4Rw4oscpZvcgsSYwSwQimpn0fRuwoxc66PbAnzagRWXaywn3yA/nxWQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1696607375; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9q17Rnwalf8d2r5qhJCl4UbgZm/wHnyRkams51NJ4NA=; b=o2Ywy+Xxv4644j7E3z5iXmU9bWY93aesw3JQJreuO6MDgKa9XBBlpMr6/08b8Kr3uLF34U 2T0GbLhtiNCRYeCA== From: Sebastian Andrzej Siewior To: Jakub Kicinski Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, "David S. Miller" , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Eric Dumazet , Hao Luo , Jesper Dangaard Brouer , Jiri Olsa , John Fastabend , Jonathan Lemon , KP Singh , Maciej Fijalkowski , Magnus Karlsson , Martin KaFai Lau , Paolo Abeni , Song Liu , Stanislav Fomichev , Thomas Gleixner , Yonghong Song Subject: [PATCH bpf-next v2] net: Add a warning if NAPI cb missed xdp_do_flush(). Message-ID: <20231006154933.mQgxQHHt@linutronix.de> References: <20230929165825.RvwBYGP1@linutronix.de> <20231004070926.5b4ba04c@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20231004070926.5b4ba04c@kernel.org> X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net A few drivers were missing a xdp_do_flush() invocation after XDP_REDIRECT. Add three helper functions each for one of the per-CPU lists. Return true if the per-CPU list is non-empty and flush the list. Add xdp_do_check_flushed() which invokes each helper functions and creats a warning if one of the functions had a non-empty list. Hide everything behind CONFIG_DEBUG_NET. Suggested-by: Jesper Dangaard Brouer Signed-off-by: Sebastian Andrzej Siewior Acked-by: Jakub Kicinski --- v1…v2: - Moved xdp_do_check_flushed() to net/core/dev.h. - Stripped __ from function names. - Removed empty lines within an ifdef block. - xdp_do_check_flushed() is now behind CONFIG_DEBUG_NET && CONFIG_BPF_SYSCALL. dev_check_flush and cpu_map_check_flush are now only behind CONFIG_DEBUG_NET. They have no empty inline function for the !CONFIG_DEBUG_NET case since they are only called in CONFIG_DEBUG_NET case. include/linux/bpf.h | 3 +++ include/net/xdp_sock.h | 9 +++++++++ kernel/bpf/cpumap.c | 10 ++++++++++ kernel/bpf/devmap.c | 10 ++++++++++ net/core/dev.c | 2 ++ net/core/dev.h | 6 ++++++ net/core/filter.c | 14 ++++++++++++++ net/xdp/xsk.c | 10 ++++++++++ 8 files changed, 64 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a34ac7f00c86c..584adabd411fc 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2478,6 +2478,9 @@ void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data, enum bpf_dynptr_type type, u32 offset, u32 size); void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr); void bpf_dynptr_set_rdonly(struct bpf_dynptr_kern *ptr); + +bool dev_check_flush(void); +bool cpu_map_check_flush(void); #else /* !CONFIG_BPF_SYSCALL */ static inline struct bpf_prog *bpf_prog_get(u32 ufd) { diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h index 69b472604b86f..7dd0df2f6f8e6 100644 --- a/include/net/xdp_sock.h +++ b/include/net/xdp_sock.h @@ -109,4 +109,13 @@ static inline void __xsk_map_flush(void) #endif /* CONFIG_XDP_SOCKETS */ +#if defined(CONFIG_XDP_SOCKETS) && defined(CONFIG_DEBUG_NET) +bool xsk_map_check_flush(void); +#else +static inline bool xsk_map_check_flush(void) +{ + return false; +} +#endif + #endif /* _LINUX_XDP_SOCK_H */ diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index e42a1bdb7f536..8a0bb80fe48a3 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -764,6 +764,16 @@ void __cpu_map_flush(void) } } +#ifdef CONFIG_DEBUG_NET +bool cpu_map_check_flush(void) +{ + if (list_empty(this_cpu_ptr(&cpu_map_flush_list))) + return false; + __cpu_map_flush(); + return true; +} +#endif + static int __init cpu_map_init(void) { int cpu; diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 4d42f6ed6c11a..a936c704d4e77 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -418,6 +418,16 @@ void __dev_flush(void) } } +#ifdef CONFIG_DEBUG_NET +bool dev_check_flush(void) +{ + if (list_empty(this_cpu_ptr(&dev_flush_list))) + return false; + __dev_flush(); + return true; +} +#endif + /* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or * by local_bh_disable() (from XDP calls inside NAPI). The * rcu_read_lock_bh_held() below makes lockdep accept both. diff --git a/net/core/dev.c b/net/core/dev.c index 606a366cc2095..9273b12ecf6fa 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6526,6 +6526,8 @@ static int __napi_poll(struct napi_struct *n, bool *repoll) if (test_bit(NAPI_STATE_SCHED, &n->state)) { work = n->poll(n, weight); trace_napi_poll(n, work, weight); + + xdp_do_check_flushed(n); } if (unlikely(work > weight)) diff --git a/net/core/dev.h b/net/core/dev.h index e075e198092cc..f66125857af77 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -136,4 +136,10 @@ static inline void netif_set_gro_ipv4_max_size(struct net_device *dev, } int rps_cpumask_housekeeping(struct cpumask *mask); + +#if defined(CONFIG_DEBUG_NET) && defined(CONFIG_BPF_SYSCALL) +void xdp_do_check_flushed(struct napi_struct *napi); +#else +static inline void xdp_do_check_flushed(struct napi_struct *napi) { } +#endif #endif diff --git a/net/core/filter.c b/net/core/filter.c index a094694899c99..5d5921c0ab4a3 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4207,6 +4207,20 @@ void xdp_do_flush(void) } EXPORT_SYMBOL_GPL(xdp_do_flush); +#if defined(CONFIG_DEBUG_NET) && defined(CONFIG_BPF_SYSCALL) +void xdp_do_check_flushed(struct napi_struct *napi) +{ + bool ret; + + ret = dev_check_flush(); + ret |= cpu_map_check_flush(); + ret |= xsk_map_check_flush(); + + WARN_ONCE(ret, "Missing xdp_do_flush() invocation after NAPI by %ps\n", + napi->poll); +} +#endif + void bpf_clear_redirect_map(struct bpf_map *map) { struct bpf_redirect_info *ri; diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index f5e96e0d6e01d..ba070fd37d244 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -391,6 +391,16 @@ void __xsk_map_flush(void) } } +#ifdef CONFIG_DEBUG_NET +bool xsk_map_check_flush(void) +{ + if (list_empty(this_cpu_ptr(&xskmap_flush_list))) + return false; + __xsk_map_flush(); + return true; +} +#endif + void xsk_tx_completed(struct xsk_buff_pool *pool, u32 nb_entries) { xskq_prod_submit_n(pool->cq, nb_entries);