From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 2D293374E41; Tue, 1 Sep 2026 00:47:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788223633; cv=none; b=dv/g0YWoozk7WfRtMNed6SDkAyYh9TAE78n1X9I5mM3EY7SZDTcpVIGcSWLuFxuLC2I4G0jhJyYjDdgSATjjbkyCPZKr09vfxkyEqJ8GFTV7FEeotr+TtBdAAkU8DPKWkBELiv6Coz4DYT/3ZVbsUkaqq2K/9I6+Nx0CYk9aOhQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788223633; c=relaxed/simple; bh=0VJbYk95hqb2RJMnHeFsM0o8Xpi+Qg3RyKqte29gyRc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=cxyOSSM09O4RFW/98SlgTgbquTnEXQqItJWfBf5OFOzFavARpUqlvTyycDAwFrKU7aNcPW5S8Wehpwc2Ay5IgOPX7QGIMGg2DeUlq/4zCK+44J8LZ6iIB/vppQePipvi3fm7i6P1u4L0jDv901i9tv/s/e0HCOdPV5bTW+7JYh0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TnG5pWFb; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TnG5pWFb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07CAC1F000E9; Tue, 1 Sep 2026 00:47:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788223631; bh=nzdGXIZl7GaCZWCVfOEL58DKl2VbcTdF/XvyWbO/X5w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TnG5pWFbzs9HzWErrtFXrtRuc54bTrvlIgTYwlKthes4y/0dP/VsAHvrUHmi/ur9C YLAKMW3PLsSzKscMOBye/f3hm9aj8uh/twDGA8KVIfQ1F87V89HIK/e0zPanVI23OT MqRi3Of/7MtrJw/+3q9E5KrAMVS91gHuuUyJICPtGlm80BsZ17O+se6LPLNmvA2iER T4muY8o+eL+kgnD6qt/nhfZ1sezwPeddi7A0MR5J8M5lrtWy+NiO6xoePN5Q39u/C4 eagacR7uqLPNcjVOxXMcc1XwK8C0qjAzlriVkvt/E502d3lPBjObB+U/EHyPxmcOLD wHF7DdXdAEk3g== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Peter Zijlstra , Ingo Molnar , x86@kernel.org Cc: Jinchao Wang , Mathieu Desnoyers , Masami Hiramatsu , Thomas Gleixner , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Alexander Shishkin , Ian Rogers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH v2 1/2] tracing/probes: Fix anon_stack check for unnamed bitfields in btf_find_struct_member Date: Tue, 1 Sep 2026 09:47:05 +0900 Message-ID: <178822362571.115597.5746407820036730968.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <178822361441.115597.11442662641658772793.stgit@devnote2> References: <178822361441.115597.11442662641658772793.stgit@devnote2> User-Agent: StGit/0.19 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="utf-8" Content-Transfer-Encoding: 8bit From: Masami Hiramatsu (Google) btf_find_struct_member() traverses into nested anonymous structures and unions by pushing members with !member->name_off onto anon_stack. However, it does not consider the unnamed bitfields (e.g. `int : 5` or `unsigned int : 0`) which also have member->name_off == 0. If such an unnamed bitfield is pushed to anon_stack, the btf_find_struct_member() return an error even if there are other valid entries in anon_stack. To fix this, only push unnamed struct/union members to anon_stack. Also move the btf_type_is_struct() check to the entry of this function because now it is sure only struct/union are pushed to anon_stack. Fixes: 302db0f5b3d8 ("tracing/probes: Add a function to search a member of a struct/union") Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260830143859.D56991F00A3D@smtp.kernel.org/ Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt --- Changes in v2: - added tags. --- kernel/trace/trace_btf.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace_btf.c b/kernel/trace/trace_btf.c index 00172f301f25..d3ba356d5503 100644 --- a/kernel/trace/trace_btf.c +++ b/kernel/trace/trace_btf.c @@ -74,24 +74,24 @@ const struct btf_member *btf_find_struct_member(struct btf *btf, { struct btf_anon_stack *anon_stack; const struct btf_member *member; + const struct btf_type *mtype; u32 tid, cur_offset = 0; const char *name; int i, top = 0; + if (!btf_type_is_struct(type)) + return ERR_PTR(-EINVAL); + anon_stack = kzalloc_objs(*anon_stack, BTF_ANON_STACK_MAX); if (!anon_stack) return ERR_PTR(-ENOMEM); retry: - if (!btf_type_is_struct(type)) { - member = ERR_PTR(-EINVAL); - goto out; - } - for_each_member(i, type, member) { if (!member->name_off) { /* Anonymous union/struct: push it for later use */ - if (btf_type_skip_modifiers(btf, member->type, &tid) && + mtype = btf_type_skip_modifiers(btf, member->type, &tid); + if (mtype && btf_type_is_struct(mtype) && top < BTF_ANON_STACK_MAX) { anon_stack[top].tid = tid; anon_stack[top++].offset =