From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794275675; b=27ejqcf83/qHyG53D7MslZhXxgKnc5aeGxUiKOw9bG4C3dLmlroDvNehAJQFpK6mK0+i mUQlverlHwDHMe1UUZsxMIvijw0xz3xE/AFSj20UaIQuTixkyFOtS6N/z0H5T8QSct6nx +t0BaUiODuCWqwuti3HpcbCgUGMRZBiPyZGdwjWLVf1WMV4pRarili82nMVJOS1BB6hPH Mp9IDTRdScs6ne9XOiKmJGGVgWfM0DZ5tyRU4y0ieGp2DKKxOQAptmvF3BGnGqCAXwUhI FDt8AF41CY2a6oeW6ib62DiaT+1sfjGxD72j1WaqLMDpRbQ4lreLoVGFqw7QRq78cGw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794275675; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=54yQrXtTo6n4glyDMJvBhVg56JBFe8LLpx850k4k4Zg=; b=n0CZePChRBRMDIzxObPt7HzymbeRHs/JCg1QY7i4k+WXK+Oa47rNlR51jcjQCXs8wvPC IiKJR9xjvWLX9tVaWFv/YzqWzNwZXk2xY6qRHAQoXUaUnBDeNcq1arJ23OHClOesMr9Fk y1rfOdL/xy3X1kqvtQSsC9E5d3tMJeENKWx2h+MmWB568NbN/yyRO47Pom7+9K/Yj+bvT Wz7OYbasg+gExMjoi+Kpo3z+EBtBoNOjnzdqCGm3bMAsAHSbK8nwpM6kReBZcFvnt9All /MCzC+xNS1upqg5Oi2ELSi/3WkE0bHrdYiL08s1tWyTVyQzQEgD4yh+37+iYZYWqyhA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=LnWHx1jo; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A148606A321; Tue, 10 Nov 2026 01:54:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=LnWHx1jo Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E18C1F0089F; Tue, 10 Nov 2026 01:54:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794275675; bh=54yQrXtTo6n4glyDMJvBhVg56JBFe8LLpx850k4k4Zg=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=LnWHx1joezvBzDTRHvu09MaFP2S6CZpYZDF5ERfZemweOc3X5JtbkUrw3KVlcLTKu GI8nCmhZJan1ktXLWyxyABEZYsHZO5Ea+6pnBAlGVLqSJwj9QgoHywmlR3V2wuCxzc FepWZ9BweL4nPJ7C3kCSRnfaT7KSayxTWGVju5kId6OoYatT/kvbi5YYv1EYjBgcL2 chUQWA9CNQYKnUie5UJsD2R1oTZOMaZnVt1rkiI/gp9UR0mBP3aGAN+y+L58fweDL5 gRyLKckX/3fA10+Bl1PExtYJbOhBIAaoxNY2oxZkUC0iEtEflE5YT4zEs1u0fdKXyV JyMf8k6sSVTrg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v7 04/10] riscv: stacktrace: Add frame record metadata Reply-To: sashiko-reviews@lists.linux.dev To: "Shuai Xue" , palmer@dabbelt.com, pjw@kernel.org, aou@eecs.berkeley.edu Cc: alex@ghiti.fr, oleg@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, mark.rutland@arm.com, peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, james.clark@linaro.org, jpoimboe@kernel.org, jikos@kernel.org, mbenes@suse.cz, pmladek@suse.com, joe.lawrence@redhat.com, shuah@kernel.org, mpdesouza@suse.com, martin@kaiser.cx, kmehltretter@gmail.com, oliver.yang@linux.alibaba.com, zhuo.song@linux.alibaba.com, jkchen@linux.alibaba.com, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, live-patching@vger.kernel.org In-Reply-To: <20261110013750.36800-5-xueshuai@linux.alibaba.com> References: <20260914092648.51254-1-xueshuai@linux.alibaba.com> <20261110013750.36800-1-xueshuai@linux.alibaba.com> <20261110013750.36800-5-xueshuai@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 10 Nov 2026 01:54:33 +0000 X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Thank you for your contribution! Sashiko AI review found 1 potential issue to consider: - [Medium] riscv: entry: use call instead of tail for handle_bad_stack() -- commit ed05329452fecde9e16a00910af1efec91f2922b Author: Wang Han riscv: stacktrace: Add frame record metadata This commit adds a metadata frame record to struct pt_regs and initializes it across exception, overflow, boot, and task-creation entry boundaries for frame-pointer stack unwinding. > diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S > index 61b7a77166971..4c69132d59785 100644 > --- a/arch/riscv/kernel/entry.S > +++ b/arch/riscv/kernel/entry.S [ ... ] > @@ -354,6 +376,19 @@ SYM_CODE_START_LOCAL(handle_kernel_stack_overflow) > REG_S s3, PT_BADADDR(sp) > REG_S s4, PT_CAUSE(sp) > REG_S s5, PT_TP(sp) > + > + /* > + * Create a metadata frame record for the overflow pt_regs. The > + * overflow path is entered from kernel context, so this is a nested > + * pt_regs boundary and the unwinder can resume from the pre-overflow > + * frame pointer saved in PT_S0. > + */ > + REG_S zero, (S_STACKFRAME + FRAME_RECORD_FP)(sp) > + REG_S zero, (S_STACKFRAME + FRAME_RECORD_RA)(sp) > + li t0, FRAME_META_TYPE_PT_REGS > + REG_S t0, S_STACKFRAME_TYPE(sp) > + addi s0, sp, S_STACKFRAME + STACKFRAME_RECORD_SIZE > + > move a0, sp > tail handle_bad_stack > SYM_CODE_END(handle_kernel_stack_overflow) [Severity: Medium] Should this use "call handle_bad_stack" instead of "tail handle_bad_stack"? Because tail does not update ra, handle_bad_stack()'s prologue saves a frame record on the overflow stack that pairs the new s0 (pointing at the overflow pt_regs metadata record) with the interrupted pre-overflow ra. When panic() unwinds from handle_bad_stack(), the unwinder consumes regs->ra before reaching the pt_regs metadata record, and if that return address was hooked by function_graph or kretprobes, recovering it with the overflow-stack fp fails and aborts the stack trace before reaching the overflowed task stack. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261110013750.3680= 0-1-xueshuai@linux.alibaba.com?part=3D4