linux-kernel - Re: [PATCH 0/2] blktrace: fix trace buffer leak and limit trace buffer size

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Message-ID: <YGKHFbQ6vfdVroZ7@T590>
Date:   Tue, 30 Mar 2021 10:04:05 +0800
From:   Ming Lei <ming.lei@...hat.com>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     linux-block@...r.kernel.org, Christoph Hellwig <hch@....de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/2] blktrace: fix trace buffer leak and limit trace
 buffer size

On Tue, Mar 23, 2021 at 04:14:38PM +0800, Ming Lei wrote:
> blktrace may pass big trace buffer size via '-b', meantime the system
> may have lots of CPU cores, so too much memory can be allocated for
> blktrace.
> 
> The 1st patch shutdown bltrace in blkdev_close() in case of task
> exiting, for avoiding trace buffer leak.
> 
> The 2nd patch limits max trace buffer size for avoiding potential
> OOM.
> 
> 
> Ming Lei (2):
>   block: shutdown blktrace in case of fatal signal pending
>   blktrace: limit allowed total trace buffer size
> 
>  fs/block_dev.c          |  6 ++++++
>  kernel/trace/blktrace.c | 32 ++++++++++++++++++++++++++++++++
>  2 files changed, 38 insertions(+)

Hello Guys,

Ping...

BTW, this is another OOM risk in blktrace userspace which is caused by
mlock(16 * buffer_size) * nr_cpus, so I think we need to avoid memory
leak caused by OOM.


Thanks,
Ming