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Date: Thu, 11 Apr 2024 20:17:53 +0800
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Subject: Re: [PATCH 6.6] Revert "dm-crypt, dm-verity: disable tasklets"
To: Greg KH <gregkh@linuxfoundation.org>
CC: <stable@vger.kernel.org>, <mpatocka@redhat.com>,
	<torvalds@linux-foundation.org>, <tglx@linutronix.de>,
	<linux-kernel@vger.kernel.org>, <dm-devel@lists.linux.dev>,
	<msnitzer@redhat.com>, <ignat@cloudflare.com>, <damien.lemoal@wdc.com>,
	<bob.liu@oracle.com>, <houtao1@huawei.com>, <nhuck@google.com>,
	<peterz@infradead.org>, <mingo@elte.hu>, <yukuai3@huawei.com>,
	<yangerkun@huawei.com>, <yi.zhang@huawei.com>, <lilingfeng@huaweicloud.com>
References: <20240411091539.361470-1-lilingfeng3@huawei.com>
 <2024041103-reputable-bobsled-585f@gregkh>
From: Li Lingfeng <lilingfeng3@huawei.com>
In-Reply-To: <2024041103-reputable-bobsled-585f@gregkh>
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There is no need to revert it in Linus's tree since the expanded 
workqueue can work like tasklet.
https://lore.kernel.org/lkml/20240130091300.2968534-1-tj@kernel.org/

I'm not sure if the problem described in [1] could be triggered by a 
scenario I haven't considered. So I only send the revert patch to 6.6 
mainly for comments.
Of course, I think the other branches need it too.

Thanks

在 2024/4/11 17:52, Greg KH 写道:
> On Thu, Apr 11, 2024 at 05:15:39PM +0800, Li Lingfeng wrote:
>> This reverts commit 5735a2671ffb70ea29ca83969fe01316ee2ed6fc which is
>> commit 0a9bab391e336489169b95cb0d4553d921302189 upstream.
>>
>> Tasklet is thought to cause memory corruption [1], so it was disabled in
>> dm-crypt and dm-verity. However, memory corruption may not happen since
>> cc->io_queue is created without WQ_UNBOUND [2].
>> Revert commit 5735a2671ffb ("dm-crypt, dm-verity: disable tasklets") to
>> bring tasklet back.
>>
>> [1] https://lore.kernel.org/all/d390d7ee-f142-44d3-822a-87949e14608b@suse.de/T/
>> [2] https://lore.kernel.org/all/4d331659-badd-749d-fba1-271543631a8a@huawei.com/
>>
>> Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
>> ---
>>   drivers/md/dm-crypt.c         | 38 +++++++++++++++++++++++++++++++++--
>>   drivers/md/dm-verity-target.c | 26 ++++++++++++++++++++++--
>>   drivers/md/dm-verity.h        |  1 +
>>   3 files changed, 61 insertions(+), 4 deletions(-)
> What is the commit id of this in Linus's tree?  And why only 6.6.y?
>
> thanks,
>
> greg k-h
>