From patchwork Wed Mar 5 16:38:05 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sudeep Holla X-Patchwork-Id: 871670 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 984DA191F66; Wed, 5 Mar 2025 16:39:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741192742; cv=none; b=JTG+tEY4KIF7TXz1vz2HZitkEWgxWvX14uMz2g383GpBwDo4zjyS/7X7tj7YF0I7BiLnmlw1nevVM9l8o/sbq0KVfWTvSi4c1qKzMZkVgrXdrMXBzro+oG2FM5a9iq0GxngSi/SaciasvsmamK7di1ti2AoRxPU3LZGD3kswq/s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741192742; c=relaxed/simple; bh=g9voXRH9b5scUtRJQUT9IkYk1Q1woAlbAN5ZVwPOsw0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Fg7iJndJEgQnpmhqRKt/aHrF6ZppVUHH92u8a9FuvrsdAOswGhSyEEeZvgH/SkIEuEHTxH+MxP37Us0OBD9vBYFbZyBrzuQZ/+2BtRwWdoPGwHwC0JElQTPFs4u3rC02cer+8Nczvl1c6E3n5U2Uam3QooBQnNdT7IeDnTQgGFA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 266831007; Wed, 5 Mar 2025 08:39:13 -0800 (PST) Received: from e133711.arm.com (e133711.arm.com [10.1.196.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B2C653F5A1; Wed, 5 Mar 2025 08:38:58 -0800 (PST) From: Sudeep Holla Date: Wed, 05 Mar 2025 16:38:05 +0000 Subject: [PATCH v2 01/13] mailbox: pcc: Fix the possible race in updation of chan_in_use flag Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250305-pcc_fixes_updates-v2-1-1b1822bc8746@arm.com> References: <20250305-pcc_fixes_updates-v2-0-1b1822bc8746@arm.com> In-Reply-To: <20250305-pcc_fixes_updates-v2-0-1b1822bc8746@arm.com> To: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Sudeep Holla , Jassi Brar , Huisong Li , Adam Young , Robbie King X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3054; i=sudeep.holla@arm.com; h=from:subject:message-id; bh=V6iDNkf7FB8p7g5HOzBVjRnuDYthQbqnBHp6HSZoQ4M=; b=owEBbQKS/ZANAwAIAQBBurwxfuKYAcsmYgBnyH4eFfRXbdJVo7fM20REaros5LzuuqUZWFuvu uS87yr5R6OJAjMEAAEIAB0WIQS6ceUSBvMeskPdk+EAQbq8MX7imAUCZ8h+HgAKCRAAQbq8MX7i mOQlEAC4nSoZMV7mnkebG2/TGHeV/HEO2YzCQrnCqwREIy9tOmVfsIEB35W6nF/44S8O0XvrkqU QYaXpjsbm2gDJAHsSFsVc/+FCCweCrjZXOAtK4Sd/G8kp1dAcxYXbzXDu9A4bmX7Buh8Rkzegu1 DWsE1/S7Wqct7EW0/ZAsZlzwZm26+IVThJYUb3crunt/5JYiKWGOg4k/EoKHzRWTtv7KMMATaY5 mGHkjictRTm+IZmUWc6Hqs9gL3fVXvdktNKIO1EwOs8Ek6SKy3PIEBxTlnM6sopyYlcvKq+x0LT +X1iZQKR0zCNJNlwH1g+yy/IGaos971c2yy4+Ah8Zb9EhUHHzVbhJSIMckjGe2GkTUGbMwgCKVg 4R1Ytq8Sv1yz28RAJFQ93RGNo0F+YOwxb31+75FTfoGxqsNv75xNNawvXsVgtZQy3dg0Bqk1LWD Es3Ni6QkRPtXvZ7Wg1PfU4BGkzg65txP6MnfMGzMVxMkLvSmOj4zRVywHyvQmJtJ3jgLwhPM2Af 4y0Y64VUmdi2Wm+OKts7G6qEu/Ds1xlW/KUxsc1Rked2puMJxRYtgBePFvTWdfqxqEQRXorJ/XE VxEYy+XjiZzN/qlA6pBW3fj7jNXrBhZvp+g8xw3C/wmdXd2XtufD/alex0Aq1TK/lIsxZgElOXs AdUXeFmWVUBic5Q== X-Developer-Key: i=sudeep.holla@arm.com; a=openpgp; fpr=7360A21742ADF5A11767C1C139CFD4755FE2D5B4 From: Huisong Li The function mbox_chan_received_data() calls the Rx callback of the mailbox client driver. The callback might set chan_in_use flag from pcc_send_data(). This flag's status determines whether the PCC channel is in use. However, there is a potential race condition where chan_in_use is updated incorrectly due to concurrency between the interrupt handler (pcc_mbox_irq()) and the command sender(pcc_send_data()). The 'chan_in_use' flag of a channel is set to true after sending a command. And the flag of the new command may be cleared erroneous by the interrupt handler afer mbox_chan_received_data() returns, As a result, the interrupt being level triggered can't be cleared in pcc_mbox_irq() and it will be disabled after the number of handled times exceeds the specified value. The error log is as follows: | kunpeng_hccs HISI04B2:00: PCC command executed timeout! | kunpeng_hccs HISI04B2:00: get port link status info failed, ret = -110 | irq 13: nobody cared (try booting with the "irqpoll" option) | Call trace: | dump_backtrace+0x0/0x210 | show_stack+0x1c/0x2c | dump_stack+0xec/0x130 | __report_bad_irq+0x50/0x190 | note_interrupt+0x1e4/0x260 | handle_irq_event+0x144/0x17c | handle_fasteoi_irq+0xd0/0x240 | __handle_domain_irq+0x80/0xf0 | gic_handle_irq+0x74/0x2d0 | el1_irq+0xbc/0x140 | mnt_clone_write+0x0/0x70 | file_update_time+0xcc/0x160 | fault_dirty_shared_page+0xe8/0x150 | do_shared_fault+0x80/0x1d0 | do_fault+0x118/0x1a4 | handle_pte_fault+0x154/0x230 | __handle_mm_fault+0x1ac/0x390 | handle_mm_fault+0xf0/0x250 | do_page_fault+0x184/0x454 | do_translation_fault+0xac/0xd4 | do_mem_abort+0x44/0xb4 | el0_da+0x40/0x74 | el0_sync_handler+0x60/0xb4 | el0_sync+0x168/0x180 | handlers: | pcc_mbox_irq | Disabling IRQ #13 To solve this issue, pcc_mbox_irq() must clear 'chan_in_use' flag before the call to mbox_chan_received_data(). Signed-off-by: Huisong Li (sudeep.holla: Minor updates to the subject and commit message) Signed-off-by: Sudeep Holla --- drivers/mailbox/pcc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c index 82102a4c5d68839170238540a6fed61afa5185a0..f2e4087281c70eeb5b9b33371596613a371dff4f 100644 --- a/drivers/mailbox/pcc.c +++ b/drivers/mailbox/pcc.c @@ -333,10 +333,15 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p) if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack)) return IRQ_NONE; + /* + * Clear this flag immediately after updating interrupt ack register + * to avoid possible race in updatation of the flag from + * pcc_send_data() that could execute from mbox_chan_received_data() + */ + pchan->chan_in_use = false; mbox_chan_received_data(chan, NULL); check_and_ack(pchan, chan); - pchan->chan_in_use = false; return IRQ_HANDLED; }