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Date: Mon, 4 Mar 2024 09:35:48 +0200
From: Leon Romanovsky <leon@kernel.org>
To: Wenchao Hao <haowenchao2@huawei.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>, linux-rdma@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RDMA/restrack: Fix potential invalid address access
Message-ID: <20240304073548.GA13620@unreal>
References: <20240301095514.3598280-1-haowenchao2@huawei.com>
 <20240303125737.GB112581@unreal>
 <a7b2409c-4a3b-472d-a23a-87b12530be6d@huawei.com>
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On Mon, Mar 04, 2024 at 11:21:19AM +0800, Wenchao Hao wrote:
> On 2024/3/3 20:57, Leon Romanovsky wrote:
> > On Fri, Mar 01, 2024 at 05:55:15PM +0800, Wenchao Hao wrote:
> > > struct rdma_restrack_entry's kern_name was set to KBUILD_MODNAME
> > > in ib_create_cq(), while if the module exited but forgot del this
> > > rdma_restrack_entry, it would cause a invalid address access in
> > > rdma_restrack_clean() when print the owner of this rdma_restrack_entry.
> > 
> > How is it possible to exit owner module without cleaning the resources?
> > 
> 
> I meet this issue with one of our product who develop their owner kernel
> modules based on ib_core, and there are terrible logic with the exit
> code which cause resource leak.
> 
> Of curse it's bug of module who did not clear resource when exit, but
> I think ib_core should avoid accessing memory of other modules directly
> to provides better stability.
> 
> What's more, from the context of rdma_restrack_clean() when print
> "restack: %s %s object allocated by %s is not freed ...", it seems
> designed for the above scene where client has bug to alerts there
> are resource leak, so we should not panic on this log print.

Can you please share the kernel panic?

Thanks