From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="VXkjzuM/" Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E962210F8; Fri, 8 Dec 2023 12:36:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Vwp6H7hbWYuJntJS7kS+l0fw/Z+oOc8mMbOkVe4byro=; b=VXkjzuM/7GoObftnaEWoZgdFYY L5xDBcOtO5SXticci6clYrj1K1KscYr+MoTjFYUkZz0ZWWNRoMSMcKuxO0tsaM3zEfH6eF3zU5j8O cUQI6yZ66caIvr7dscGTiK/hdDneafs8+XW2NtmcUWud886gJjMgBetRpivFI+2k3nYvnsQp65YfB hU4YX9RUqEib/aVz06p8+wivpoxMEz+kH1paTVnnirP857fswwl5sTiNJ8EbLZQRfKs655qDWsKpA jp0nWHX5uHWgqj/v4iexBNwei3DfCgzFy0X4rATHIUUHZG65pJYjJNbS3wxpBgX7DtbfBf97DzDCW GFrHBhQQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1rBhZP-006WtK-Ib; Fri, 08 Dec 2023 20:35:35 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 3799630050D; Fri, 8 Dec 2023 21:35:35 +0100 (CET) Date: Fri, 8 Dec 2023 21:35:35 +0100 From: Peter Zijlstra To: Alexei Starovoitov Cc: Jiri Olsa , Song Liu , Song Liu , Paul Walmsley , Palmer Dabbelt , Albert Ou , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , X86 ML , "H. Peter Anvin" , "David S. Miller" , David Ahern , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Arnd Bergmann , Sami Tolvanen , Kees Cook , Nathan Chancellor , Nick Desaulniers , linux-riscv , LKML , Network Development , bpf , linux-arch , clang-built-linux , Josh Poimboeuf , Joao Moreira , Mark Rutland Subject: Re: [PATCH v2 2/2] x86/cfi,bpf: Fix BPF JIT call Message-ID: <20231208203535.GG36716@noisy.programming.kicks-ass.net> References: <20231206163814.GB36423@noisy.programming.kicks-ass.net> <20231206183713.GA35897@noisy.programming.kicks-ass.net> <20231207093105.GA28727@noisy.programming.kicks-ass.net> <20231208102940.GB28727@noisy.programming.kicks-ass.net> <20231208134041.GD28727@noisy.programming.kicks-ass.net> <20231208172152.GD36716@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-arch@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: On Fri, Dec 08, 2023 at 11:40:27AM -0800, Alexei Starovoitov wrote: > typedef void (*btf_dtor_kfunc_t)(void *); > btf_dtor_kfunc_t dtor; > but the bpf_cgroup_release takes 'struct cgroup*'. > From kcfi pov void * == struct cgroup * ? > Do we need to change it to 'void *cgrp' ? Yes, doing that naively like the below, gets me lovely things like: validate_case:FAIL:expect_msg unexpected error: -22 VERIFIER LOG: ============= ============= EXPECTED MSG: 'Possibly NULL pointer passed to trusted arg0' #48/7 cgrp_kfunc/cgrp_kfunc_acquire_untrusted:FAIL run_subtest:PASS:obj_open_mem 0 nsec libbpf: extern (func ksym) 'bpf_cgroup_release': func_proto [148] incompatible with vmlinux [125610] libbpf: failed to load object 'cgrp_kfunc_failure' But let me try rebuilding everything.. --- diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index b3be5742d6f1..078b207af7f0 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2145,10 +2145,11 @@ __bpf_kfunc struct task_struct *bpf_task_acquire(struct task_struct *p) * bpf_task_release - Release the reference acquired on a task. * @p: The task on which a reference is being released. */ -__bpf_kfunc void bpf_task_release(struct task_struct *p) +__bpf_kfunc void bpf_task_release(void *p) { put_task_struct_rcu_user(p); } +EXPORT_SYMBOL_GPL(bpf_task_release); #ifdef CONFIG_CGROUPS /** @@ -2169,10 +2170,11 @@ __bpf_kfunc struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp) * drops to 0. * @cgrp: The cgroup on which a reference is being released. */ -__bpf_kfunc void bpf_cgroup_release(struct cgroup *cgrp) +__bpf_kfunc void bpf_cgroup_release(void *cgrp) { cgroup_put(cgrp); } +EXPORT_SYMBOL_GPL(bpf_cgroup_release); /** * bpf_cgroup_ancestor - Perform a lookup on an entry in a cgroup's ancestor