From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 34941E66886 for ; Sat, 20 Dec 2025 03:20:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8560B6B0089; Fri, 19 Dec 2025 22:20:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7FFAA6B008A; Fri, 19 Dec 2025 22:20:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 702456B008C; Fri, 19 Dec 2025 22:20:19 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 60CCC6B0089 for ; Fri, 19 Dec 2025 22:20:19 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 07F7A140426 for ; Sat, 20 Dec 2025 03:20:19 +0000 (UTC) X-FDA: 84238396158.03.4CF8C63 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) by imf04.hostedemail.com (Postfix) with ESMTP id 22D0B40005 for ; Sat, 20 Dec 2025 03:20:16 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=AqfSN9En; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf04.hostedemail.com: domain of roman.gushchin@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1766200817; a=rsa-sha256; cv=none; b=fIuP+3dzfk8Z7Inj4cA20RYaUsqfWHZoG3x+Ojl1efx74YGWtEagKKEkvhy2HVGcn8cP/2 R/BoPBBaFLY3hDIITFg+ngAqHaDkdXWGTocWsIT7Hqgm4CNIuTd9UsuGGROVPl4fnTihat tSf0dYE3yONW4x9EQ+8Z9bllR2HDO/Q= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=AqfSN9En; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf04.hostedemail.com: domain of roman.gushchin@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1766200817; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=KSWnxPF7s7XrgaAgGOnY7K1GNIzL+YqDV6JYLvAhZaU=; b=Bk3EVGMkVRlJcq43MpLmXZYeUSRrtfnCVlWz1ZeENIissqthe+q/2jx73vJ+Y947OGR/Wx JaR8fbZwsEr7EoeME9qiSnxGxLCc74BnB6EZmc/SrvL1FyvmtBr5/TP65B7MmzxyxIFlbR weTJA2OS9RHSLiUed3AvlbUD3FNqshY= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1766200810; 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: in-reply-to:in-reply-to:references:references; bh=KSWnxPF7s7XrgaAgGOnY7K1GNIzL+YqDV6JYLvAhZaU=; b=AqfSN9EnBu+pQ+55c6KrxraFWofHwRehkLXlObC2WQPuyODI6sRp51PUDiCH3FSpSQ7hHV WCMjBb/r91usuQ1LiKsr/XDzXH2rvZl2CtPrYl/dV9uHmZAF0fjFp3qytDa7/4JaXToPF3 h06Y8zGnLjlifMc3TK1SqU1GZykFUFQ= From: Roman Gushchin To: Shakeel Butt Cc: bpf@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, JP Kobryn , Alexei Starovoitov , Daniel Borkmann , Michal Hocko , Johannes Weiner Subject: Re: [PATCH bpf-next v1 6/6] bpf: selftests: selftests for memcg stat kfuncs In-Reply-To: <2xhmcrporen72rskghn6hmg6obnojptuerwzqgu7mqzhnxaxs5@33dxlwa6rqlh> (Shakeel Butt's message of "Fri, 19 Dec 2025 15:07:11 -0800") References: <20251219015750.23732-1-roman.gushchin@linux.dev> <20251219015750.23732-7-roman.gushchin@linux.dev> <2xhmcrporen72rskghn6hmg6obnojptuerwzqgu7mqzhnxaxs5@33dxlwa6rqlh> Date: Fri, 19 Dec 2025 19:20:04 -0800 Message-ID: <87cy49g7q3.fsf@linux.dev> MIME-Version: 1.0 Content-Type: text/plain X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 22D0B40005 X-Stat-Signature: 8oej84nxu8nms8cpranhkuayuodzse3k X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1766200816-244508 X-HE-Meta: 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 m3IcToAv H8DtR2QotoQqdKm3cInTe3mnPGqyeEUSfQCdV3NH3asHDxJQxKrZrj0fnQ6xoKwOL4LOy4rSh37UUAOJbEnXh9jXNz3FoKShb1zNzuMGUbEbqNfSDwgE1tBsx3ZdzlbajJQdZ4X/ZX4bNe6Y1iyCeNK94lE3Qd6OlPVNVdkkMuLR07aPi/E5tqu8auBvFEL7fhp6LvxTOucfhhzf1dNdVGyxirQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Shakeel Butt writes: > On Thu, Dec 18, 2025 at 05:57:50PM -0800, Roman Gushchin wrote: >> From: JP Kobryn >> >> Add test coverage for the kfuncs that fetch memcg stats. Using some common >> stats, test scenarios ensuring that the given stat increases by some >> arbitrary amount. The stats selected cover the three categories represented >> by the enums: node_stat_item, memcg_stat_item, vm_event_item. >> >> Since only a subset of all stats are queried, use a static struct made up >> of fields for each stat. Write to the struct with the fetched values when >> the bpf program is invoked and read the fields in the user mode program for >> verification. >> >> Signed-off-by: JP Kobryn > > Need your signoff Sure, will add, thanks. > > [...] >> + >> +#define NR_PIPES 64 >> +static void test_kmem(struct bpf_link *link, struct memcg_query *memcg_query) >> +{ >> + int fds[NR_PIPES][2], i; >> + >> + /* >> + * Increase kmem value by creating pipes which will allocate some >> + * kernel buffers. >> + */ >> + for (i = 0; i < NR_PIPES; i++) { >> + if (!ASSERT_OK(pipe(fds[i]), "pipe")) >> + goto cleanup; >> + } >> + >> + if (!ASSERT_OK(read_stats(link), "read stats")) >> + goto cleanup; >> + >> + ASSERT_GT(memcg_query->memcg_kmem, 0, "kmem value"); >> + >> +cleanup: >> + for (i = 0; i < NR_PIPES; i++) { > > Instead of from 0 to NR_PIPES, we need to go from i-1 to (and equal to) 0 > otherwise we can potentially close() junk values. Good catch, will fix. > >> + close(fds[i][0]); >> + close(fds[i][1]); >> + } >> +} >> + > > [...] > >> + >> +SEC("iter.s/cgroup") >> +int cgroup_memcg_query(struct bpf_iter__cgroup *ctx) >> +{ >> + struct cgroup *cgrp = ctx->cgroup; >> + struct cgroup_subsys_state *css; >> + struct mem_cgroup *memcg; >> + >> + if (!cgrp) >> + return 1; >> + >> + css = &cgrp->self; >> + if (!css) > > Will css ever be NULL here? Hm, I think previously the verifier wasn't smart enough to understand that it's always a valid pointer, but I just tested it with linux-next and it worked well. I'll drop the check. Thanks!