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From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: tingwei@codeaurora.org, mathieu.poirier@linaro.org,
	alexander.shishkin@linux.intel.com
Cc: tsoni@codeaurora.org, saiprakash.ranjan@codeaurora.org,
	kim.phillips@arm.com, jinlmao@codeaurora.org,
	gregkh@linuxfoundation.org, coresight@lists.linaro.org,
	rdunlap@infradead.org, ykaukab@suse.de, linux@armlinux.org.uk,
	leo.yan@linaro.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 19/20] coresight: add try_get_module() in coresight_grab_device()
Date: Wed, 22 Jul 2020 11:49:48 +0100	[thread overview]
Message-ID: <7ef8d427-23c9-10cd-b337-03ae75476a8c@arm.com> (raw)
In-Reply-To: <20200717054536.7052-20-tingwei@codeaurora.org>

Hi Tingwei,

On 07/17/2020 06:45 AM, Tingwei Zhang wrote:
> When coresight device is in an active session, driver module of
> that device should not be removed. Use try_get_module() in
> coresight_grab_device() to prevent module to be unloaded.
> 

Is this really sufficient ? AFAIU, a device could be removed, but the
module may still be alive due to the refcount on the module. This
could imply that we have stale pointers in the _path_, which could
lead to corruption elsewhere. Should we do a get/put_device() instead ?

Cheers
Suzuki

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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-07-22 10:46 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-17  5:45 [PATCH v3 00/20] coresight: allow to build coresight as modules Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 01/20] coresight: cpu_debug: add module name in Kconfig Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 02/20] coresight: cpu_debug: define MODULE_DEVICE_TABLE Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 03/20] coresight: use IS_ENABLED for CONFIGs that may be modules Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 04/20] coresight: add coresight prefix to barrier_pkt Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 05/20] coresight: export global symbols Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 06/20] Allow to build coresight-stm as a module, for ease of development Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 07/20] coresight: allow etm3x to be built as a module Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 08/20] coresight: allow etm4x " Tingwei Zhang
2020-07-17 17:05   ` Mike Leach
2020-07-18  3:25     ` tingwei
2020-07-18 17:38       ` Mike Leach
2020-07-21 14:55         ` Mathieu Poirier
2020-07-21 23:22           ` tingwei
2020-07-20  6:58   ` Sai Prakash Ranjan
2020-07-21  7:03     ` Sai Prakash Ranjan
2020-07-17  5:45 ` [PATCH v3 09/20] coresight: allow etb " Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 10/20] coresight: allow tpiu " Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 11/20] coresight: allow tmc " Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 12/20] coresight: remove multiple init calls from funnel driver Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 13/20] coresight: remove multiple init calls from replicator driver Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 14/20] coresight: allow funnel and replicator drivers to be built as modules Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 15/20] coresight: cti: add function to register cti associate ops Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 16/20] coresight: allow cti to be built as a module Tingwei Zhang
2020-07-20 17:00   ` Mike Leach
2020-07-20 21:07     ` Mike Leach
2020-07-21 16:35       ` Mike Leach
2020-07-21 23:27         ` tingwei
2020-07-17  5:45 ` [PATCH v3 17/20] coresight: tmc-etr: add function to register catu ops Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 18/20] coresight: allow catu drivers to be built as modules Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 19/20] coresight: add try_get_module() in coresight_grab_device() Tingwei Zhang
2020-07-22 10:49   ` Suzuki K Poulose [this message]
2020-07-22 10:48     ` Greg KH
2020-07-22 11:26       ` Suzuki K Poulose
2020-07-23  0:18         ` tingwei
2020-07-23  0:35       ` tingwei
2020-07-22 10:51     ` Suzuki K Poulose
2020-07-23  0:19       ` tingwei
2020-07-23 19:36     ` Mathieu Poirier
2020-07-24  1:17       ` Tingwei Zhang
2020-07-17  5:45 ` [PATCH v3 20/20] coresight: allow the coresight core driver to be built as a module Tingwei Zhang

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