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=1793427351; b=cspTl0Nf4Xb1H6MmP5r5cZmfQQ3fF7JPy4+1BnC+tRfMsICsqDHCRz3rf8iKcKCAuh8R vJjs/4pmf09ZQLs/3s8xaUJxbxE+rnomcrcQLMJeNaFtQxYRiZZAK01odonU6WSZO6/NU kRhEUt3bAQa2o/4OYkpCn2VaHMUnyjrgfW3Zk5uUEp/vje85HVGjy7z7mcr1C336uqPM5 DV+v48cuvN4Yf7BVg1fDy++/X5i3UMaGn6YfNjeiomjtQp4qXzK/7uwngdM5FJGL5XU3g HEXJqLJ13rX5n4y8NjJTpkzQ+NtyYZkPJkPU+cRLAzPtLSixbr4GK42LyRpFKsHiQrw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793427351; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=6SAPhStgskZ3/Kbb+Kc3vmxkFmycCrYzErbtoPMpR9c=; b=W35GR+pZ1YTgwSXkguVAF9OV0lxt8pC/An1qjunRk390sFEhyINJ9/WfkYkdGbDUGiBZ ehWfPj62fHaq770Atzosa4bzeVg84CfqQGyCNe4GzrLNaRuhw9c3NcZRTgMmlE9+ZJHLH CH/P00UInjzEX4TpTkTwXmdJ9p73vZeTAL00iS7/gmH20qe+cDq0sCIH6b2rZl9HtmEi+ SuEH8oqSxgEL63o2F0BzzXqadJO3UhKAnrDG5ClnYvimYm7QnSZ1+KcraV2yueh43YGwa Uqbmstr8EMbYTToyA5gYYRcwfv1HNKrVTVcJ+Kakfc/mn31uzBfxa6B4XQ24OkLHCeQ== 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=T58NbKNZ; 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 47B2F606A31A for ; Sat, 31 Oct 2026 06:15:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=T58NbKNZ Received: by smtp.kernel.org (Postfix) with ESMTPSA id A15511F000C1; Sat, 31 Oct 2026 06:15:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793427350; bh=6SAPhStgskZ3/Kbb+Kc3vmxkFmycCrYzErbtoPMpR9c=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=T58NbKNZFDq2XMefMwutC9l3U3omuN5IsBfJQ1dam8fn6aHLFmR32M9GH2BU0uuic leC+bqrCMiBpkZRMvjHF4/vyCDIhzIrTnIo8yRo3hnDHxUkHghpWxkIEFOSYZYOaBn Zry2zfG5VAS2eRQurBzt83JxacHm1fZQ3Bc32MvnBNHSN2Mrk6v6NiOiXUA5+kRNgu cypShnU2/YfARlgkdB9gChZ8eZOL/Hw0rM0oiqvlXbdSnzrKsP46EFuX8NNGB+hGUP eMvrCqdtQfbRardH0uj1L1SB0qOy2F1553jRYkwLXRwjSF9tCi7a85KEzOcnV+TYgN 0v7Kaq8lyOv6Q== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2] perf docs: Correct JIT_CODE_UNWINDING_INFO specification Reply-To: sashiko-reviews@lists.linux.dev To: "Letian Jiang" Cc: linux-perf-users@vger.kernel.org In-Reply-To: References: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 31 Oct 2026 06:15:50 +0000 X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > The JIT_CODE_UNWINDING_INFO description places the EH Frame Header before > the EH Frame. However, jit_add_eh_frame_info() uses the beginning of the > unwinding data for .eh_frame and the trailing eh_frame_hdr_size bytes for > .eh_frame_hdr. >=20 > Correct the unwinding_data description and the eh_frame_hdr_size field > description to match the layout consumed by perf. >=20 > Also document that an unwinding record precedes and applies to the next > JIT_CODE_LOAD record. perf caches the unwinding data and uses it when > processing that load record. >=20 > Revise the mapped_size note to describe frame-pointer-based unwinding as > a possibility depending on the backend and valid frame pointers in the > generated code. >=20 > The libunwind-specific use case still matters: its EH Frame Header fields > through fde_count are read directly from the ELF file, while lookup-table > and EH Frame accesses require a mapping covering those addresses. An > empty lookup table can trigger frame-pointer-based unwinding fallback > without mapping the unwinding data. This does not impose the same access > requirements on other unwinding backends. >=20 > Signed-off-by: Letian Jiang Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/CYXPR84MB347640EF28= 4BED04EADB0B4A826C2@CYXPR84MB3476.NAMPRD84.PROD.OUTLOOK.COM?part=3D1