From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) (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 2FA3F4E1C8 for ; Mon, 29 Jan 2024 06:39:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706510389; cv=none; b=pLN0iF7PqU35QLgyS+ps9blBFrW6Vug1a8/oLS+pMxbnxsqJ+y4Nf2/LCcr81rpLpuTj9OGYnMA3ssxJGpoTLSi/uxTyYVIG7cz5ZKh8MVtZgMYrS5KLWZHVZ5J1ZQf9tl57anNCh9enyTeOEWqRohY3k9AA2dpYATBtMfKqbuw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706510389; c=relaxed/simple; bh=B5ADz3m5i2u2lMzDcjGq4jF37gAxqS/1AYz26oq+fNc=; h=From:To:Cc:Subject:Date:Message-Id; b=tvFMhAa8FWUzEVEb2Vk6P7voiHFriHWM2Ifx6avZtjP64mjFngNxyeccRc9wGMwxfGkyP+jKou0eUpD3FdpOL2E2EgZycwi0uxeY+Xg6+F6xEommEYPqdNWpJNg3w0oqr7Xgcr2LB2nQpjfPcnhZ2uBDJgDf4jhjSVskB/iqP4Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=S4t98/Zu; arc=none smtp.client-ip=198.175.65.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="S4t98/Zu" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1706510388; x=1738046388; h=from:to:cc:subject:date:message-id; bh=B5ADz3m5i2u2lMzDcjGq4jF37gAxqS/1AYz26oq+fNc=; b=S4t98/ZuE52IeIp5JZTG8ZZWLWsfLmh8FyKkTYExIO9wORZNlrVs5q+4 rt3sIqGCJNk8C3fWcFXcxKOm14Uwil+nEfhwA1jPvcgKrOTsvxrOdMxyu BC7dM697HFfjJ3KS2Q9vF98CJU+0QMYULtEaBstfN5OIzlwiwiNp+Z4Yg 8DisZATJp2j0nLndDlUVPhrPe/c+5xwuPxUM/bkeD9NKefk5r1qmzdOUv uGituuNNFKubdug1nOEGZdneKbjlj5IopQOtESSDlo6fT6K9Ef4lSSLN/ wFzXAPFXZ+ttP5maDY1JMt3TRFUu3Yp5pmw/E/BKD1Aojg574RO9leQsY Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10967"; a="9977257" X-IronPort-AV: E=Sophos;i="6.05,226,1701158400"; d="scan'208";a="9977257" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2024 22:39:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,226,1701158400"; d="scan'208";a="36028748" Received: from qiuxu-clx.sh.intel.com ([10.239.53.109]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2024 22:39:26 -0800 From: Qiuxu Zhuo To: tglx@linutronix.de, dave.hansen@linux.intel.com, tony.luck@intel.com, bp@alien8.de, kirill.shutemov@linux.intel.com, peterz@infradead.org, mingo@redhat.com Cc: x86@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, qiuxu.zhuo@intel.com Subject: [PATCH 1/1] x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups Date: Mon, 29 Jan 2024 14:38:42 +0800 Message-Id: <20240129063842.61584-1-qiuxu.zhuo@intel.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: During the memory error injection test on kernels >= v6.4, kernel panics occurred like below. However, this issue couldn't be reproduced on kernels <= v6.3. mce: [Hardware Error]: CPU 296: Machine Check Exception: f Bank 1: bd80000000100134 mce: [Hardware Error]: RIP 10: {__get_user_nocheck_4+0x6/0x20} mce: [Hardware Error]: TSC 411a93533ed ADDR 346a8730040 MISC 86 mce: [Hardware Error]: PROCESSOR 0:a06d0 TIME 1706000767 SOCKET 1 APIC 211 microcode 80001490 mce: [Hardware Error]: Run the above through 'mcelog --ascii' mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel Kernel panic - not syncing: Fatal local machine check MCE can recover from an in-kernel #MC if the fixup type is EX_TYPE_UACCESS, explicitly indicating that the kernel is attempting to access userspace memory. However, MCE can only panic the kernel for an in-kernel #MC if the fixup type is EX_TYPE_DEFAULT as it includes various fixup types that MCE may not recover from. ex_handler_uaccess() would throw a #GP WARN_ONCE() if users gave non-canonical addresses (with bit 63 clear) to {get, put}_user(), which was unexpected. Therefore, the previous commit 'b19b74bc99b1' replaced _ASM_EXTABLE_UA() with _ASM_EXTABLE() for {get, put}_user() fixups where the corresponding exception handler ex_handler_default() does not have a #GP WARN_ONCE(). However, the new fixup type EX_TYPE_DEFAULT resulted in the mentioned kernel panic. The subsequent commit '6014bc27561f2' (merged in v6.4) added the check gp_fault_address_ok() right before #GP WARN_ONCE() in ex_handler_uaccess(). This check can avoid the #GP WARN_ONCE() for a non-canonical address (with bit63 clear) in ex_handler_uaccess(). So with the subsequent commit '6014bc27561f2', now it's OK to revert to _ASM_EXTABLE_UA() for {get,put}_user() exception fixups as it can both avoid the #GP WARN_ONCE() in ex_handler_uaccess() and fix the panic mentioned above. Fixes: b19b74bc99b1 ("x86/mm: Rework address range check in get_user() and put_user()") Signed-off-by: Qiuxu Zhuo Reviewed-by: Kirill A. Shutemov --- arch/x86/lib/getuser.S | 24 ++++++++++++------------ arch/x86/lib/putuser.S | 20 ++++++++++---------- 2 files changed, 22 insertions(+), 22 deletions(-) diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index 20ef350a60fb..10d5ed8b5990 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -163,23 +163,23 @@ SYM_CODE_END(__get_user_8_handle_exception) #endif /* get_user */ - _ASM_EXTABLE(1b, __get_user_handle_exception) - _ASM_EXTABLE(2b, __get_user_handle_exception) - _ASM_EXTABLE(3b, __get_user_handle_exception) + _ASM_EXTABLE_UA(1b, __get_user_handle_exception) + _ASM_EXTABLE_UA(2b, __get_user_handle_exception) + _ASM_EXTABLE_UA(3b, __get_user_handle_exception) #ifdef CONFIG_X86_64 - _ASM_EXTABLE(4b, __get_user_handle_exception) + _ASM_EXTABLE_UA(4b, __get_user_handle_exception) #else - _ASM_EXTABLE(4b, __get_user_8_handle_exception) - _ASM_EXTABLE(5b, __get_user_8_handle_exception) + _ASM_EXTABLE_UA(4b, __get_user_8_handle_exception) + _ASM_EXTABLE_UA(5b, __get_user_8_handle_exception) #endif /* __get_user */ - _ASM_EXTABLE(6b, __get_user_handle_exception) - _ASM_EXTABLE(7b, __get_user_handle_exception) - _ASM_EXTABLE(8b, __get_user_handle_exception) + _ASM_EXTABLE_UA(6b, __get_user_handle_exception) + _ASM_EXTABLE_UA(7b, __get_user_handle_exception) + _ASM_EXTABLE_UA(8b, __get_user_handle_exception) #ifdef CONFIG_X86_64 - _ASM_EXTABLE(9b, __get_user_handle_exception) + _ASM_EXTABLE_UA(9b, __get_user_handle_exception) #else - _ASM_EXTABLE(9b, __get_user_8_handle_exception) - _ASM_EXTABLE(10b, __get_user_8_handle_exception) + _ASM_EXTABLE_UA(9b, __get_user_8_handle_exception) + _ASM_EXTABLE_UA(10b, __get_user_8_handle_exception) #endif diff --git a/arch/x86/lib/putuser.S b/arch/x86/lib/putuser.S index 2877f5934177..975c9c18263d 100644 --- a/arch/x86/lib/putuser.S +++ b/arch/x86/lib/putuser.S @@ -133,15 +133,15 @@ SYM_CODE_START_LOCAL(__put_user_handle_exception) RET SYM_CODE_END(__put_user_handle_exception) - _ASM_EXTABLE(1b, __put_user_handle_exception) - _ASM_EXTABLE(2b, __put_user_handle_exception) - _ASM_EXTABLE(3b, __put_user_handle_exception) - _ASM_EXTABLE(4b, __put_user_handle_exception) - _ASM_EXTABLE(5b, __put_user_handle_exception) - _ASM_EXTABLE(6b, __put_user_handle_exception) - _ASM_EXTABLE(7b, __put_user_handle_exception) - _ASM_EXTABLE(9b, __put_user_handle_exception) + _ASM_EXTABLE_UA(1b, __put_user_handle_exception) + _ASM_EXTABLE_UA(2b, __put_user_handle_exception) + _ASM_EXTABLE_UA(3b, __put_user_handle_exception) + _ASM_EXTABLE_UA(4b, __put_user_handle_exception) + _ASM_EXTABLE_UA(5b, __put_user_handle_exception) + _ASM_EXTABLE_UA(6b, __put_user_handle_exception) + _ASM_EXTABLE_UA(7b, __put_user_handle_exception) + _ASM_EXTABLE_UA(9b, __put_user_handle_exception) #ifdef CONFIG_X86_32 - _ASM_EXTABLE(8b, __put_user_handle_exception) - _ASM_EXTABLE(10b, __put_user_handle_exception) + _ASM_EXTABLE_UA(8b, __put_user_handle_exception) + _ASM_EXTABLE_UA(10b, __put_user_handle_exception) #endif -- 2.17.1