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 2F6EB210F4; Tue, 16 Jan 2024 19:43:12 +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=1705434192; cv=none; b=rg4BgHn9p4/HankOhmMt5O+7m9PX9/a8z6VJHvGNpV3JeAwbjH5igKZBOqiZi8KZtFoIysMUS/qLVdQNNNMGHiX/bjTQMIRrGEeFEct4YFOWtceVPO0fayogwTaNEJXvqhNOb9WDLtmgLh7/YR92pd0lPuZ4g+6nXtUTpYqR6SM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705434192; c=relaxed/simple; bh=SbYuKDxHsGMaRqy5BeSJ2nJhg+gbOCrbiKmg/fWiFzw=; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version:X-stable: X-Patchwork-Hint:X-stable-base:Content-Transfer-Encoding; b=uUhkht614EOcZky/OQujUn829OSBXQ7XiDKCHm6dnPmoZhg4e48XdfXZuRFUBDvMubynmWF0yBtRJtmpF0jG7qDazhT6e9z+2H6cgtoBkQacMLKlDotIbz0O8+YBkdrVRRWQVCaGV1X7cBwf6K76yn1RXMnQ87776iPr2j0x4tE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gz6iU7ek; 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="gz6iU7ek" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2355C433F1; Tue, 16 Jan 2024 19:43:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705434192; bh=SbYuKDxHsGMaRqy5BeSJ2nJhg+gbOCrbiKmg/fWiFzw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gz6iU7ek1YVxzqnz/9A9Sm8oWaHGNlYrVRtyWbpTsVkc22PfTZWkSbdVFM0JnRx9B K105DYFkYGEC4imrpyE1yQDpdVLeiQfUg1TT9G2nicJkEuFiEqdBby4hjxfcMZGRwD bZKWN6L38ObXYSgNG5O7I2+k+ubLOQPtXDeUmN8/H0GHD3nXLiMhOY/C2N9v/K2kxl UMpNZUxuKIH/G0AZWrDtF8pd0se4GgVrmvOS/Dv++SIYX45O7whGG5GZr0yBg2TbZq POj2mACpE+7+ocwsUHwBeZ8LnPrx2xqw9kEymMWdRMhYTpXOKcmfEjdYHJhSNunAaV TN7SKyUjh/r5w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: HariBabu Gattem , Jay Buddhabhatti , Michal Simek , Sasha Levin , abhyuday.godhasara@xilinx.com, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 6.7 014/108] soc: xilinx: Fix for call trace due to the usage of smp_processor_id() Date: Tue, 16 Jan 2024 14:38:40 -0500 Message-ID: <20240116194225.250921-14-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240116194225.250921-1-sashal@kernel.org> References: <20240116194225.250921-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.7 Content-Transfer-Encoding: 8bit From: HariBabu Gattem [ Upstream commit daed80ed07580e5adc0e6d8bc79933a35154135a ] When preemption is enabled in kernel and if any task which can be preempted should not use smp_processor_id() directly, since CPU switch can happen at any time, the previous value of cpu_id differs with current cpu_id. As a result we see the below call trace during xlnx_event_manager_probe. [ 6.140197] dump_backtrace+0x0/0x190 [ 6.143884] show_stack+0x18/0x40 [ 6.147220] dump_stack_lvl+0x7c/0xa0 [ 6.150907] dump_stack+0x18/0x34 [ 6.154241] check_preemption_disabled+0x124/0x134 [ 6.159068] debug_smp_processor_id+0x20/0x2c [ 6.163453] xlnx_event_manager_probe+0x48/0x250 To protect cpu_id, It is recommended to use get_cpu()/put_cpu() to disable preemption, get the cpu_id and enable preemption respectively. (For Reference, Documentation/locking/preempt-locking.rst and Documentation/kernel-hacking/hacking.rst) Use preempt_disable()/smp_processor_id()/preempt_enable() API's to achieve the same. Signed-off-by: HariBabu Gattem Signed-off-by: Jay Buddhabhatti Link: https://lore.kernel.org/r/20231027055622.21544-1-jay.buddhabhatti@amd.com Signed-off-by: Michal Simek Signed-off-by: Sasha Levin --- drivers/soc/xilinx/xlnx_event_manager.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/soc/xilinx/xlnx_event_manager.c b/drivers/soc/xilinx/xlnx_event_manager.c index 86a048a10a13..edfb1d5c10c6 100644 --- a/drivers/soc/xilinx/xlnx_event_manager.c +++ b/drivers/soc/xilinx/xlnx_event_manager.c @@ -555,7 +555,7 @@ static void xlnx_disable_percpu_irq(void *data) static int xlnx_event_init_sgi(struct platform_device *pdev) { int ret = 0; - int cpu = smp_processor_id(); + int cpu; /* * IRQ related structures are used for the following: * for each SGI interrupt ensure its mapped by GIC IRQ domain @@ -592,9 +592,12 @@ static int xlnx_event_init_sgi(struct platform_device *pdev) sgi_fwspec.param[0] = sgi_num; virq_sgi = irq_create_fwspec_mapping(&sgi_fwspec); + cpu = get_cpu(); per_cpu(cpu_number1, cpu) = cpu; ret = request_percpu_irq(virq_sgi, xlnx_event_handler, "xlnx_event_mgmt", &cpu_number1); + put_cpu(); + WARN_ON(ret); if (ret) { irq_dispose_mapping(virq_sgi); -- 2.43.0