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Date:   Tue, 27 Sep 2022 10:14:31 -0300
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Li Zhijian <lizhijian@fujitsu.com>
Cc:     zyjzyj2000@gmail.com, leon@kernel.org, linux-rdma@vger.kernel.org,
        linux-kernel@vger.kernel.org, Bob Pearson <rpearsonhpe@gmail.com>
Subject: Re: [PATCH jgg-for-next] RDMA/rxe: Fix pd refcount_t: underflow;
 use-after-free
Message-ID: <YzL3N533TE8T3k1c@ziepe.ca>
References: <20220927052530.21397-1-lizhijian@fujitsu.com>
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On Tue, Sep 27, 2022 at 01:25:30PM +0800, Li Zhijian wrote:
> In the error path, both rxe_put(pd) and rxe_cleanup(mr) will
> drop pd's ref_cont.
> rxe_cleanup(mr)
>  -> __rxe_cleanup
>    -> rxe_put(mr->elem)
>    -> rxe_mr_cleanup(mr)
>      -> rxe_put(mr_pd(mr))
> 
> [342431.583189] ------------[ cut here ]------------
> [342431.585051] refcount_t: underflow; use-after-free.
> [342431.586677] WARNING: CPU: 0 PID: 660500 at lib/refcount.c:28 refcount_warn_saturate+0xcd/0x120
> [342431.605247] RIP: 0010:refcount_warn_saturate+0xcd/0x120
> [342431.661981]  __rxe_cleanup+0x1c3/0x1e0 [rdma_rxe]
> [342431.663260]  rxe_dealloc_pd+0x16/0x20 [rdma_rxe]
> [342431.664883]  ib_dealloc_pd_user+0x95/0xd0 [ib_core]
> [342431.666803]  destroy_hw_idr_uobject+0x46/0x90 [ib_uverbs]
> [342431.668514]  uverbs_destroy_uobject+0xc8/0x360 [ib_uverbs]
> [342431.670232]  __uverbs_cleanup_ufile+0x157/0x210 [ib_uverbs]
> [342431.671920]  ? uverbs_destroy_uobject+0x360/0x360 [ib_uverbs]
> 
> CC: Bob Pearson <rpearsonhpe@gmail.com>
> Fixes: 0d0e4b528c3b ("RDMA/rxe: Set pd early in mr alloc routines")
> Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
> ---
> I have to say i made a mistake in previous review, I missed this WARN_ONCE messages.
> And the V6 patch that i had applied fix this problem in another way.

Does this mean I took the wrong patch? The patchworks got messed up
for this series somehow

I'll squash this diff in..

Jason