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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 684E8C4332F for ; Mon, 25 Oct 2021 21:20:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0C01960C51 for ; Mon, 25 Oct 2021 21:20:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 0C01960C51 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 93FA8940008; Mon, 25 Oct 2021 17:20:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8ED76940007; Mon, 25 Oct 2021 17:20:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7B70B940008; Mon, 25 Oct 2021 17:20:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0139.hostedemail.com [216.40.44.139]) by kanga.kvack.org (Postfix) with ESMTP id 6CDDE940007 for ; Mon, 25 Oct 2021 17:20:48 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 24E061814BA21 for ; Mon, 25 Oct 2021 21:20:48 +0000 (UTC) X-FDA: 78736229376.25.7777880 Received: from mail-pf1-f170.google.com (mail-pf1-f170.google.com [209.85.210.170]) by imf05.hostedemail.com (Postfix) with ESMTP id 4B4AF5085962 for ; Mon, 25 Oct 2021 21:20:38 +0000 (UTC) Received: by mail-pf1-f170.google.com with SMTP id f11so12139079pfc.12 for ; Mon, 25 Oct 2021 14:20:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=NfrrVRCciJICOev8gMVBuAQquLy9VSfP1uEbEqVM24w=; b=H2EpbH8CK+eyq1Svymbl0Dbfo2kpVmHsKpcpd8aOlyPgS9egcampbijVN2rYBa4Rgn p7a+kyLwjWzm6IJXev9oy30YE4CPP1J9p6CFzIEnGFOIGhjk7GBbSz5REtZqbByQpuoA zURwII3gv6rc2pNshcM6TV+ht6kflPX4D3tGE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=NfrrVRCciJICOev8gMVBuAQquLy9VSfP1uEbEqVM24w=; b=vM4NGfJQWaxb3sm1KEWMgKdp8pKEVOpi2Yk7dgvcDZ14IZQgogK6qdZSigazqhRJQF 73bY52dAStLq2L1e76gOqq608h/+kpKpZr+dz6zyWeWFZk2nyWeOW3j3LGZcD/4HL1jl ZuJEpXO0/vGQyDN+RbHTNvFdTfen0YwG8GlJnZ8oG6/DsfvY1ZTYGy5wo9qg1KVSLRCH cJCdU3a4lovXHQZhes18ZNehuVYQbCKqOxDtH9rP3B1Xk+dIVXoDgIU2IrubjTpCuS0t 7gHyQmopPsU2TfR0zJ76OE6uN2py1u5Mcn52APtFHg5ckk8O6Z02elAtQB+jS3kn0joa hhLg== X-Gm-Message-State: AOAM532UGUenFhXMGt5zsG1ia5K0OWxkXswWADDIAGRB07+pgwXCrwNb /nnKjIN9nW1cQWE3puyuS30bRQ== X-Google-Smtp-Source: ABdhPJyh2X1uSEHHHblNKO5f1PiBaklcfwz/rKHbsu1YaXrG1EqQDih9hnPhQ9fPP+X9SJoGD+kUag== X-Received: by 2002:aa7:8d88:0:b0:47b:d965:fbb2 with SMTP id i8-20020aa78d88000000b0047bd965fbb2mr17526856pfr.16.1635196846138; Mon, 25 Oct 2021 14:20:46 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id u4sm20477372pfh.147.2021.10.25.14.20.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Oct 2021 14:20:45 -0700 (PDT) Date: Mon, 25 Oct 2021 14:20:45 -0700 From: Kees Cook To: Yafang Shao Cc: akpm@linux-foundation.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Andrii Nakryiko Subject: Re: [PATCH v6 06/12] samples/bpf/test_overhead_kprobe_kern: make it adopt to task comm size change Message-ID: <202110251420.9D2C7731@keescook> References: <20211025083315.4752-1-laoar.shao@gmail.com> <20211025083315.4752-7-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211025083315.4752-7-laoar.shao@gmail.com> X-Stat-Signature: thhuaat1uufmhj5qma6r9q6ytpggtr3o X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 4B4AF5085962 Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=H2EpbH8C; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf05.hostedemail.com: domain of keescook@chromium.org designates 209.85.210.170 as permitted sender) smtp.mailfrom=keescook@chromium.org X-HE-Tag: 1635196838-854025 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: On Mon, Oct 25, 2021 at 08:33:09AM +0000, Yafang Shao wrote: > bpf_probe_read_kernel_str() will add a nul terminator to the dst, then > we don't care about if the dst size is big enough. This patch also > replaces the hard-coded 16 with TASK_COMM_LEN to make it adopt to task > comm size change. > > Signed-off-by: Yafang Shao > Cc: Mathieu Desnoyers > Cc: Arnaldo Carvalho de Melo > Cc: Andrii Nakryiko > Cc: Peter Zijlstra > Cc: Steven Rostedt > Cc: Al Viro > Cc: Kees Cook > Cc: Petr Mladek As these are samples, I guess it's fine to change their sizes. Reviewed-by: Kees Cook > --- > samples/bpf/test_overhead_kprobe_kern.c | 11 ++++++----- > samples/bpf/test_overhead_tp_kern.c | 5 +++-- > 2 files changed, 9 insertions(+), 7 deletions(-) > > diff --git a/samples/bpf/test_overhead_kprobe_kern.c b/samples/bpf/test_overhead_kprobe_kern.c > index f6d593e47037..8fdd2c9c56b2 100644 > --- a/samples/bpf/test_overhead_kprobe_kern.c > +++ b/samples/bpf/test_overhead_kprobe_kern.c > @@ -6,6 +6,7 @@ > */ > #include > #include > +#include > #include > #include > #include > @@ -22,17 +23,17 @@ int prog(struct pt_regs *ctx) > { > struct signal_struct *signal; > struct task_struct *tsk; > - char oldcomm[16] = {}; > - char newcomm[16] = {}; > + char oldcomm[TASK_COMM_LEN] = {}; > + char newcomm[TASK_COMM_LEN] = {}; > u16 oom_score_adj; > u32 pid; > > tsk = (void *)PT_REGS_PARM1(ctx); > > pid = _(tsk->pid); > - bpf_probe_read_kernel(oldcomm, sizeof(oldcomm), &tsk->comm); > - bpf_probe_read_kernel(newcomm, sizeof(newcomm), > - (void *)PT_REGS_PARM2(ctx)); > + bpf_probe_read_kernel_str(oldcomm, sizeof(oldcomm), &tsk->comm); > + bpf_probe_read_kernel_str(newcomm, sizeof(newcomm), > + (void *)PT_REGS_PARM2(ctx)); > signal = _(tsk->signal); > oom_score_adj = _(signal->oom_score_adj); > return 0; > diff --git a/samples/bpf/test_overhead_tp_kern.c b/samples/bpf/test_overhead_tp_kern.c > index eaa32693f8fc..80edadacb692 100644 > --- a/samples/bpf/test_overhead_tp_kern.c > +++ b/samples/bpf/test_overhead_tp_kern.c > @@ -4,6 +4,7 @@ > * modify it under the terms of version 2 of the GNU General Public > * License as published by the Free Software Foundation. > */ > +#include > #include > #include > > @@ -11,8 +12,8 @@ > struct task_rename { > __u64 pad; > __u32 pid; > - char oldcomm[16]; > - char newcomm[16]; > + char oldcomm[TASK_COMM_LEN]; > + char newcomm[TASK_COMM_LEN]; > __u16 oom_score_adj; > }; > SEC("tracepoint/task/task_rename") > -- > 2.17.1 > -- Kees Cook