From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-179.mta0.migadu.com (out-179.mta0.migadu.com [91.218.175.179]) (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 A0D5723182C for ; Thu, 29 May 2025 19:11:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748545885; cv=none; b=Bx3WaUWc3hget/5O5eZrq/EhouDBEqG55QVzFvi1X7ILEmMn87GYG2nVA45CGrkNGR1TPWnzAT4XuUUWR4z4BkgYs0C92XSScTCBZCzDryDijpHS/Jj7xq/Baqd0FPFDo0qpsPF2M4S0gtai3GyAvYhS3w99BaX80YTV165i8xU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748545885; c=relaxed/simple; bh=2GfZWnG2Z9jmk7IVPvdqOZKTBamXSAvEzhnT6ZVuIog=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cP1daJAABzgQaUHIqmwzA3WIRJQWCw84f6ehKmING+rJEA8WDyO4IiRdSTOP7wC7S/ux3yKzMF4kAWUYv5waJSKje2b/XlKSwdkv6VGDKGOWiVnm4znlsSu9R7fCwSLstZg2vNjE3SHIgEH52EVUQV3Wo10Ktco5d9JXir5ckeo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=saOQuajq; arc=none smtp.client-ip=91.218.175.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="saOQuajq" Message-ID: <99d3b3ef-44f7-4f93-a8e8-ec303dd6d750@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1748545878; 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=GsLNV8w5Mk5SRqqTg1+3C9oZjlD06gLMBrLL9uNprEU=; b=saOQuajqoTkxw/CTjSJ5QTYXkA1wa5YMrGDGrX455yd9mnEV32eM5Ul+RCw8NPGs1xV66x dZ0VhI0JOjZr4vuwtRguud1YYPDAVvqMa96JVQLC65s4drPC5Ch5A8BY78fqHacvICuu1j 612gdrzzD4QySu6dJvJKhhK2BbGur90= Date: Thu, 29 May 2025 12:11:11 -0700 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v4 1/5] cgroup: move rstat base stat objects into their own struct Content-Language: en-GB To: Ihor Solodrai , JP Kobryn , tj@kernel.org, shakeel.butt@linux.dev, yosryahmed@google.com, mkoutny@suse.com, hannes@cmpxchg.org, akpm@linux-foundation.org Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, kernel-team@meta.com, bpf@vger.kernel.org References: <20250404011050.121777-1-inwardvessel@gmail.com> <20250404011050.121777-2-inwardvessel@gmail.com> <6f688f2e-7d26-423a-9029-d1b1ef1c938a@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yonghong Song In-Reply-To: <6f688f2e-7d26-423a-9029-d1b1ef1c938a@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 5/29/25 11:58 AM, Ihor Solodrai wrote: > On 4/3/25 6:10 PM, JP Kobryn wrote: >> This non-functional change serves as preparation for moving to >> subsystem-based rstat trees. The base stats are not an actual subsystem, >> but in future commits they will have exclusive rstat trees just as other >> subsystems will. >> >> Moving the base stat objects into a new struct allows the >> cgroup_rstat_cpu >> struct to become more compact since it now only contains the minimum >> amount >> of pointers needed for rstat participation. Subsystems will (in future >> commits) make use of the compact cgroup_rstat_cpu struct while >> avoiding the >> memory overhead of the base stat objects which they will not use. >> >> An instance of the new struct cgroup_rstat_base_cpu was placed on the >> cgroup struct so it can retain ownership of these base stats common >> to all >> cgroups. A helper function was added for looking up the cpu-specific >> base >> stats of a given cgroup. Finally, initialization and variable names were >> adjusted where applicable. >> >> Signed-off-by: JP Kobryn >> --- >>   include/linux/cgroup-defs.h | 38 ++++++++++------- >>   kernel/cgroup/cgroup.c      |  8 +++- >>   kernel/cgroup/rstat.c       | 84 ++++++++++++++++++++++--------------- >>   3 files changed, 79 insertions(+), 51 deletions(-) >> > > Hi everyone. > > BPF CI started failing after recent upstream merges (tip: 90b83efa6701). > I bisected the issue to this patch, see a log snippet below [1]: > >     ##[error]#44/9 btf_tag/btf_type_tag_percpu_vmlinux_helper >     load_btfs:PASS:could not load vmlinux BTF 0 nsec >     test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu 0 nsec >     libbpf: prog 'test_percpu_helper': BPF program load failed: -EACCES >     libbpf: prog 'test_percpu_helper': -- BEGIN PROG LOAD LOG -- >     0: R1=ctx() R10=fp0 >     ; int BPF_PROG(test_percpu_helper, struct cgroup *cgrp, const char > *path) @ btf_type_tag_percpu.c:58 >     0: (79) r1 = *(u64 *)(r1 +0) >     func 'cgroup_mkdir' arg0 has btf_id 437 type STRUCT 'cgroup' >     1: R1_w=trusted_ptr_cgroup() >     ; cpu = bpf_get_smp_processor_id(); @ btf_type_tag_percpu.c:63 >     1: (7b) *(u64 *)(r10 -8) = r1         ; R1_w=trusted_ptr_cgroup() > R10=fp0 fp-8_w=trusted_ptr_cgroup() >     2: (85) call bpf_get_smp_processor_id#8       ; > R0_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=1,var_off=(0x0; 0x1)) >     3: (79) r1 = *(u64 *)(r10 -8)         ; R1_w=trusted_ptr_cgroup() > R10=fp0 fp-8_w=trusted_ptr_cgroup() >     ; cgrp->self.rstat_cpu, cpu); @ btf_type_tag_percpu.c:65 >     4: (79) r1 = *(u64 *)(r1 +32)         ; > R1_w=percpu_ptr_css_rstat_cpu() >     ; rstat = (struct cgroup_rstat_cpu *)bpf_per_cpu_ptr( @ > btf_type_tag_percpu.c:64 >     5: (bc) w2 = w0                       ; > R0_w=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=1,var_off=(0x0; > 0x1)) > R2_w=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=1,var_off=(0x0; > 0x1)) >     6: (85) call bpf_per_cpu_ptr#153      ; > R0=ptr_or_null_css_rstat_cpu(id=2) >     ; if (rstat) { @ btf_type_tag_percpu.c:66 >     7: (15) if r0 == 0x0 goto pc+1        ; R0=ptr_css_rstat_cpu() >     ; *(volatile int *)rstat; @ btf_type_tag_percpu.c:68 >     8: (61) r1 = *(u32 *)(r0 +0) >     cannot access ptr member updated_children with moff 0 in struct > css_rstat_cpu with off 0 size 4 >     processed 9 insns (limit 1000000) max_states_per_insn 0 > total_states 1 peak_states 1 mark_read 1 >     -- END PROG LOAD LOG -- >     libbpf: prog 'test_percpu_helper': failed to load: -EACCES >     libbpf: failed to load object 'btf_type_tag_percpu' >     libbpf: failed to load BPF skeleton 'btf_type_tag_percpu': -EACCES > test_btf_type_tag_vmlinux_percpu:FAIL:btf_type_tag_percpu_helper > unexpected error: -13 (errno 13) > > The test in question [2]: > > SEC("tp_btf/cgroup_mkdir") > int BPF_PROG(test_percpu_helper, struct cgroup *cgrp, const char *path) > { >     struct cgroup_rstat_cpu *rstat; >     __u32 cpu; > >     cpu = bpf_get_smp_processor_id(); >     rstat = (struct cgroup_rstat_cpu > *)bpf_per_cpu_ptr(cgrp->rstat_cpu, cpu); >     if (rstat) { >         /* READ_ONCE */ >         *(volatile int *)rstat; // BPF verification fails here >     } > >     return 0; > } > > Any ideas about how to properly fix this? The struct cgroup_rstat_cpu is renamed to css_rstat_cpu. Most likely the test needs change. I will take a look. > > Thanks. > > [1] > https://github.com/kernel-patches/bpf/actions/runs/15316839796/job/43125242673 > [2] > https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/tree/tools/testing/selftests/bpf/progs/btf_type_tag_percpu.c#n68 [...]