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 E394236D9FB; Sat, 28 Feb 2026 17:57:26 +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=1772301447; cv=none; b=Z2+TSlY2rrGz/TDuZUL5+lbZ/Y5um6UEd19jUJumns592xU7TxSmQzOCeBCLv0h59aUwA0Ekn8kdSWGw2gGyOHYLmdBJ4esIWV5YGP4AvHASMrtNTvBKnYNE6vtQfo/hrKawDWTL4KwIrTSyEPkbv4YYOA7093cuCEgIaUGYnQI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772301447; c=relaxed/simple; bh=HOK6VVPwQMZSA/gCzjs8rx3EJsSJSCglVu5VDB49tKc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dJyz2A+dvyLo+LxiX9X79B/jRzr3rHZJE+YxAHrsGKZk1SR1lgfDV3+oQkEhOfleBCfeLkdyeQX3rYoHYo5/xLJYBu38gg1AqPIhV1ZYWJiCdyxDDlzE0nKgIrP9gQ29qWWY26e2BG0coiQDS9xMblSCM9t+yZomG7IalDMRN1w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YYrIy9XB; 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="YYrIy9XB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1BBAC116D0; Sat, 28 Feb 2026 17:57:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772301446; bh=HOK6VVPwQMZSA/gCzjs8rx3EJsSJSCglVu5VDB49tKc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YYrIy9XBjW7QHzxiwCpPx68H6kzGk3zAlu8IWhF7Ij9VReAfUcWUoZ6AxO2upbN6c KCHRAR4vDvQCU+9P+4FFC42lSf5ZTSvf3IQUgmXcI2r30VGzKbDghyf6gvJWhdRXVL OhJrcUbs35FHekwzuvil5Q0i6mGMLSZ+HeTpq5cjvLXnJvWATZR4IxHBRXesr/vNKm WSM8SkoqX0dbFhvcJot9TA6M7yRPUsN9WiYZopMmSJwIEByUYvDA70Lg0vvYOBrbgl WfwK7zYR120uGyXUqzgg/3LapKYmYhViVt91E0y8ciafvWlg3eVsl6BHXDSdRtVyVy nFGYVCh96TWyQ== From: Sasha Levin To: patches@lists.linux.dev Cc: Joey Gouly , David Spickett , stable@vger.kernel.org, Kevin Brodsky , Mark Rutland , Will Deacon , Sasha Levin Subject: [PATCH 6.18 633/752] arm64: poe: fix stale POR_EL0 values for ptrace Date: Sat, 28 Feb 2026 12:45:44 -0500 Message-ID: <20260228174750.1542406-633-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228174750.1542406-1-sashal@kernel.org> References: <20260228174750.1542406-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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 fd1ba43f2005a..2e9ce5a45ed2d 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1458,6 +1458,9 @@ 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