From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 EAF9640BDC5; Sat, 28 Feb 2026 17:44:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300671; cv=none; b=kaX+B+1N1zzRPhFQMivRCRTK8II/OWI5b6vhHWErNLpGzOThqYxlqtsaOz1WmrW7qFtH+icnyzz5s7vvRrWCwOF1iVBlkB9NlDPLsVPEK4COhYrKTSzMJFw4Axu0gWtSOwVaCLuP0JIsSaBkel9mSK3J6SN2vB0N4ErMEFmoqTY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300671; c=relaxed/simple; bh=R4y3wwuLIU2aPt/uQFe46IIl65jyVzKx2e0SZu1jYeg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ofYN07GPfTj0ND4jFUWXGj2TobQ+B8Om7e3QGTLfxnDnFKOrtI4DaZEET160S3ZOfPReof2jPibjgH1z+oF85vsHUhLiY05hWnPud43vd/FpfOVzuMHJ1uCKHksw5DlxBWVXxzbUQFCDG1NLbLSHTgpccS3PdFOHOlS6SYv5HEE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=udNrmW6h; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="udNrmW6h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 016FEC19425; Sat, 28 Feb 2026 17:44:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772300670; bh=R4y3wwuLIU2aPt/uQFe46IIl65jyVzKx2e0SZu1jYeg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=udNrmW6h98iTcRlb+8L/jx0nS/94NO2KMkkNqAn2Ov+JqqCRnIi9Xoe4V8b8pm/3N Dcs+TP0P3r127Ts19HMi51cn2wCV7nLaUZur3Y2kHkDJHMN52pcSqty8L2T0QBXKzF gUl3ZsFOlKSasNz2sVUFyPhnvzhWVPOkiysmcD0d7nhKqn3Y6nrmclpxR2Cj8eOQNp ENZKUUSexdlR5FhK9jCIK1yZar5oTzEFyisrqlANpZPe6sjJ3BMoxgXu0gj8mUnaQ3 x0KGTxz/hg1nmP2ePJJjdTtiqzJ9XzsqG+lEzcXIXE/ayFo3W+EGDXZzuz9c7gxUb4 83xKkLhxs0LMQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Joey Gouly , David Spickett , Kevin Brodsky , Mark Rutland , Will Deacon , Sasha Levin Subject: [PATCH 6.19 708/844] arm64: poe: fix stale POR_EL0 values for ptrace Date: Sat, 28 Feb 2026 12:30:21 -0500 Message-ID: <20260228173244.1509663-709-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228173244.1509663-1-sashal@kernel.org> References: <20260228173244.1509663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Joey Gouly [ Upstream commit 1f3b950492db411e6c30ee0076b61ef2694c100a ] If a process wrote to POR_EL0 and then crashed before a context switch happened, the coredump would contain an incorrect value for POR_EL0. The value read in poe_get() would be a stale value left in thread.por_el0. Fix this by reading the value from the system register, if the target thread is the current thread. This matches what gcs/fpsimd do. Fixes: 175198199262 ("arm64/ptrace: add support for FEAT_POE") Reported-by: David Spickett Cc: stable@vger.kernel.org Signed-off-by: Joey Gouly Cc: Kevin Brodsky Cc: Mark Rutland Reviewed-by: Kevin Brodsky Acked-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/ptrace.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 6c5ff6807d4cc..64ff87f023113 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1484,6 +1484,9 @@ static int poe_get(struct task_struct *target, if (!system_supports_poe()) return -EINVAL; + if (target == current) + current->thread.por_el0 = read_sysreg_s(SYS_POR_EL0); + return membuf_write(&to, &target->thread.por_el0, sizeof(target->thread.por_el0)); } -- 2.51.0