From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8AD7130F803 for ; Thu, 4 Jun 2026 08:00:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780560029; cv=none; b=Lt/84ozLN9w7+kvBI16u3ounpF9nqGlJtk8W7zzJyuhiqqKXTauXG9RFZFlFpGPas4mUOUehLieM3mXa7eLF7SRZqjJjyFnf8y3fsGhQvTYWFtK2vRX3ftIZ58qTB0Y89bvTRt0Ev9xGiIMVNVEPp+3ZUoFpc3uAgRlm6W0m86c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780560029; c=relaxed/simple; bh=tLNBjb1LxGgsWGmcE25Qk72vSCilUGhydTgk7Zym6qg=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E3p6nU+fz+Po6IHkT8uJwfU1zP51b6x0SWHNFUbB/k7j8g7uzz4jO5pjw1/EjQ1NiUB0Jp+Fb14AyWDr7psaVh3/ZO7dRzg1a8lgdGeZnoenLZjqmyuVeYe52WrbgN4RGhXFb5Y/+jKKgG2O5KTtPq/n6PqVY6qvHPs1vo5P+eU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=YjvY75eA; arc=none smtp.client-ip=209.85.128.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YjvY75eA" Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-490bc6a7958so5321925e9.1 for ; Thu, 04 Jun 2026 01:00:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1780560027; x=1781164827; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=5S/ODxVsZ0F1Hysh5uuXFztTRTMytWGdM0vjEW7pXv0=; b=YjvY75eADabUucunowoYWwHqVIXmxoS7hbodzR0L1O/gfSJ5DvEai8MqQqmms/QU04 kYr0O6bTFoeu7/Cyr/ZsD+axvHsuf7Pc1dqhceEkEEuAFfRFaEF7o+2n3odGlSXSUZ0g m4sIorctztaxg399WRqgdqDckdK39aDf5zz0eN50n5ZmlYfHIr/T4y/AGs30IX8gn1Sk nOWgNIYQRWQFFcfu3iogyVLN17TO0Ficrffpgu5bk9xMFRHVhBluMA8dqnZB8KrZhF6g vE0yuWxST1vv6MXbSmrAxWewfH9YZhs+ymBra4UWJed58jDhvhK+rkHSzgC/y1iiIOot WV0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780560027; x=1781164827; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=5S/ODxVsZ0F1Hysh5uuXFztTRTMytWGdM0vjEW7pXv0=; b=L3UwRCsONr3cENpn3sgDAOkzVo289wYPU649tjSAT+0LZ+M9LNS7Er8nsUejWImi/m KCb7IZS4saIZEZuGXEdxrAeHkn1yBMUjtZYxqinCVCanegkIWTuZpAFGXgjCRlvHebwu hbXdpvwHWit/m3LlOHS2q2l/L/OVGKOTVyLHXyaxRPHNl3aF/Z35Z9oKM0vS/v0CROjB ydpBa/s9ZigRjjTTpcR1hRH/iUuSdV7fn10NpSRD3fRWsr8e7xIYz0h+JOOtl17JNovn yHxrpAF03i7QswEaCqZj0F67GmI2xYLc5fV+awUVQLOcXJIXz687rxXwiH6ftf2xKsNR 3ziw== X-Forwarded-Encrypted: i=1; AFNElJ//vZW4MRFX32EVyAAi6KKvmNsY+gm0fgucg8bd/7OGwUNWOhoIloUXT8HzLuAQSqc6MjVmCkbOC4As0uBmu2/KLAg=@vger.kernel.org X-Gm-Message-State: AOJu0YycEZqy/LFPgjmeMWe2kkw6wJ4yLmT73qEcWCXVz3k74W5KEJkB ptjQ28ZGD/DgigkNLKhUHMt1eKeoZlfEK0prUikR5Pg0pV4Iu8/JVShv X-Gm-Gg: Acq92OFAkE9Jg7dDVCYJaE+/5FZQ+05GZT+Lt3LDfyVbm9psYVVl2jVQyEGDFL6uTPV 8yWr2uSzL28B6iLJehtQGwhpMCIafYHAJxqSac/7/8WxjukrCvK+hpfHv7KGfNAmV4+NxA6nan+ VMGXR/Ge7auEwcYn9cgiihJdtqFGOfo6kC4CIRqH4ZOxUDL7tp80EwZg5N2a9CRdoep7k5FmrhQ 6WlGifkzUpfb2GbdNy2RMwSK3y5visxZfGGubzgjXT/KawYkUU8gCjI9ZFCBNw9lE72a8Pr95Gs vnMMFSa/cFWWMBL3An2MYrDIUdPdzYAxEMu5EVOGiNHbLNoz6HqubksgjNKnV7nL6guLdKf75if nDWm3Ms7TNahrljuf8N8f5Qq1Xl5ntNzIqrMiGI/NEYl2UN1hMUR0qLJsyZMWNOfgYRt0+gLDfs A3JOwIOtiv8rLz2BSfJAN/43c3Fw== X-Received: by 2002:a05:600c:6095:b0:490:bb60:68ca with SMTP id 5b1f17b1804b1-490bc4b54b4mr34914705e9.3.1780560026574; Thu, 04 Jun 2026 01:00:26 -0700 (PDT) Received: from krava ([2a02:8308:a00c:e200:b655:ff13:e355:16a3]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-490b7e6c774sm67383595e9.1.2026.06.04.01.00.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Jun 2026 01:00:26 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Thu, 4 Jun 2026 10:00:23 +0200 To: bot+bpf-ci@kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, kafai@fb.com, eddyz87@gmail.com, songliubraving@fb.com, yhs@fb.com, menglong8.dong@gmail.com, rostedt@kernel.org, martin.lau@kernel.org, yonghong.song@linux.dev, clm@meta.com, ihor.solodrai@linux.dev Subject: Re: [PATCHv7 bpf-next 13/29] bpf: Add support for tracing multi link Message-ID: References: <20260603110554.29590-14-jolsa@kernel.org> <6e738b0697b9ee06e9cbaa325a3330f0447f4cd12ae54d6b2c82365d58c4c525@mail.kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6e738b0697b9ee06e9cbaa325a3330f0447f4cd12ae54d6b2c82365d58c4c525@mail.kernel.org> On Wed, Jun 03, 2026 at 11:52:13AM +0000, bot+bpf-ci@kernel.org wrote: > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > > index d853f97bd154..9e3cb547651e 100644 > > --- a/kernel/trace/bpf_trace.c > > +++ b/kernel/trace/bpf_trace.c > > @@ -42,6 +42,7 @@ > > > > #define MAX_UPROBE_MULTI_CNT (1U << 20) > > #define MAX_KPROBE_MULTI_CNT (1U << 20) > > +#define MAX_TRACING_MULTI_CNT (1U << 20) > > [ ... ] > > > @@ -3641,3 +3642,132 @@ __bpf_kfunc int bpf_copy_from_user_task_str_dynptr(const struct bpf_dynptr *dptr > > [ ... ] > > > +static int check_dup_ids(u32 *ids, u32 cnt) > > +{ > > + int err = 0; > > + > > + /* > > + * Sort ids array (together with cookies array if defined) > > + * and check it for duplicates. The ids and cookies arrays > > + * are left sorted. > > + */ > > + sort_r_nonatomic(ids, cnt, sizeof(ids[0]), ids_cmp_r, ids_swap_r, NULL); > > The sort here can run over up to MAX_TRACING_MULTI_CNT (1 << 20) elements > without ever yielding the CPU. Can this hold the CPU long enough to trip > RCU stalls or the soft lockup watchdog when cnt is large? > > This was raised on an earlier posting of the series, with the suggestion > to add a cond_resched() somewhere in the path. The reply noted that in > practice the count is expected to be closer to 100k rather than the full > 1M limit, and that it was unclear where the cond_resched() should go, so > the code was left as is. Since MAX_TRACING_MULTI_CNT is still 1 << 20, > would it be worth revisiting whether a reschedule point is needed here? we now use sort_r_nonatomic which calls cond_resched, I don't think loop below needs the cond_resched call jirka > > > + > > + for (int i = 1; i < cnt; i++) { > > + if (ids[i] == ids[i - 1]) { > > + err = -EINVAL; > > + break; > > + } > > + } > > + return err; > > +} > > > --- > AI reviewed your patch. Please fix the bug or email reply why it's not a bug. > See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md > > CI run summary: https://github.com/kernel-patches/bpf/actions/runs/26881310426