Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v2 1/7] lightnvm: pblk: fix resubmission of overwritten
 write err lbas
To:     Hans Holmberg <hans.ml.holmberg@owltronix.com>,
        Matias Bjorling <mb@lightnvm.io>
Cc:     Javier Gonzales <javier@cnexlabs.com>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Hans Holmberg <hans.holmberg@cnexlabs.com>
References: <20181105122610.1555-1-hans.ml.holmberg@owltronix.com>
 <20181105122610.1555-2-hans.ml.holmberg@owltronix.com>
From:   Sebastien Boisvert <sboisvert@gydle.com>
Openpgp: preference=signencrypt
Autocrypt: addr=sboisvert@gydle.com; keydata=
 xsFNBFi0QgMBEADLVQ63iQaeZj99I4+5AZe9ilJQ/fE7J49iS+NV3ChKgTfxMlxhagmq4a8E
 czme5AGkYeb9JAufWzcaGe4DGHJ0l26QdU/YQcpxGVGTobql+LUQ4VgEe9MxB6sMuO7QV5fZ
 aO27nCqk488ZS7e5g7Y10lMrY+4ZqzjOBIWVOXPpsDrqFY4zKuryLMtRDdINDCl+uahpIi4F
 P/c00/uGR04s+UmdZRgB1RroyZJjeSHgyR90THl8sDssR8zddaDEae2aO1/1dMI9KGamStYe
 5wo9zS4ewPAgfNxRdhsdBvCNIrU2qnKFIE9Juc59NjGPmeRUjB/iHHS6zY4BSNruWrUG5KHs
 ykHpZhP/Gg5y2RL3Pmu9vIBo5C8sUb2/sRNeWXSD7Rh/0zHtYu5T3cx3/gz71WNRhiOncZuY
 pgZltzFRxCYc9kDuthITXbI8GoR3XGq8uo2hTDBW8b+VYqLZ7n4fggkvo8f1bgt0ACVKR0nq
 JViiVO9mYDr7UUWUfS8CABAJCjsbqjxRHMEDw+UNbCS54KJ5vxxkt4LNd0nkwaVwMfrOF3mA
 foEjSmeM2NLx5SOJuMPOSRyOKjfsOgYEbFsA9hZJ34r/zAPEIdwHf57dY+nSiV/avcE6WN5P
 ks0CfGMOTBNsxyqYXPov7kkwvCb09KYU9/J6F1nM9Wm83knzewARAQABzShTZWJhc3RpZW4g
 Qm9pc3ZlcnQgPHNib2lzdmVydEBneWRsZS5jb20+wsF9BBMBCAAnBQJYtEIDAhsjBQkJZgGA
 BQsJCAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEGsrrSebZ4/xsY4QAJHIgXH9+KBNt0rgccCt
 DN4ueDoRIEmYS7NK/gUKQ8yHUreRHNpJqRSxNKzUPmvVAnnLdaopf/abhS+Ado5QGAZhiNzp
 +szWcwT4Za8P1mat+/HJznz06TwgiBJNSuMwItZmlgkBpgt2GVtmTP8LOJ1LVSD0615FO84m
 xUWqNfKijfngxQl3Ldh5TyQ4yHtdAScQVr0R1+ROIKGwjolflnzDLlb23mr2jzB/ycXo1fAo
 QLtj+Ga1cQ9ZkyRJXxicD2GsczbB/qSOMytR1iitgrxf9xtwSxHW9C1hNqb64Zr7S0ALlhhc
 nxDbOliirmcad3LFsnoHgrKWlfwj0+Qs/mjfnKiONRSWq7I1jN5wpQnY0QYm4jVRsnkAibpL
 vOqpir1qM1LNWcQ3bdvi9z5IvniB+54/QcKmtbHPAX6LCtwjd3XjfNMMEV4Lb0kCXSZdO3k2
 nG3vDOWvwVMG5gBuQUIb9iwIr5MySHieTv8ycX+TXdD8DgcjUILfz5mxEDYe8I6uyhIKwO+f
 OExGFtfgd/s7Q2pdbN/6p6zZv2Olg0TlWuB2DOERHfCCVKOSyPY4leQ7nq3jgoxk881golT7
 Sf90NqVMAnoZdXchLzqK0ChIpFB0OxbNQ2emLFgWEt93nKFo2v3C/WRoU0DizgIA7V8HdN/p
 HE8J0k2vJdH2W7mozsFNBFi0QgMBEADaEPu7lZZkv7zbZBHdC9LZLF5Blyk2Z38+9bCa60ON
 bqqXaD8sBYQO04GsoVc6FPf3EJoI2/4yFX0eh4l8aYmCfrNvm0zUWMI5T29LmchPg/zw6PW7
 qlh3kFmKqv5JmV6hdc2Exp6/VZ5C/mjbbTCcJtsOHkg22J37dbKXj2h7v1UK21i3G1HSvHwX
 YSCs7Pg7Nw2Ilkseum5wqs4UvI3T2a/0OQC7wjVSUQlKtV8bIWxNxutF7Y548m9tE5QDDtjF
 w4cIWRiOVe1EXFWASBPlJeTmrWK3/OdeKxnW7QJH/R6ebDgViG/EZPOGm+xSrznSyCwpWNWE
 tyVFSf45ow2FoVJ3z/ChvxCqXp3Jk6s0ULzyGCrGfmZJCjY8xrIW6k4dDHkr5vsygPQg3/aF
 IRmdK/aUGaQGSSAmiwRkH49gH92Y0HK2+HNL5Qp6mV3IZaSQhRs5kOG2stYUXRKhdnHKGSQz
 B1WKv5clzQGhQ9MpQX7Ch2QL+3QQVx91GPhv/Q4oAafQaX7oN1XgTPNWgbcdU+OYVjHqVWvI
 ae7HXSITVgByZAK6Di7/byqqjl1hwkiZeIcajZqK8hws6h6bLLZBn7EcZAEj8VLSdfUjJqCt
 VOZyQGdo8sNYjJPeV69vNbBUbX7BcxhxRZEYXw1rCz/xaCbNyRqRsxT03haPLg+WVQARAQAB
 wsFlBBgBCAAPBQJYtEIDAhsMBQkJZgGAAAoJEGsrrSebZ4/x13oP/2gWO3D6zo2Ok13khz4u
 +blJz8rzV1PQ5TVJmrsU05pVDlKgoZdtfEUtHlfAkzvNUpoKhNRWVN5/3QLwF4z0jfXyFYuS
 8CVMRA75h59jSABdCWvZrQLHKJV03t++IFBi3y2DUilHXrCHUxg0iJeUhbMorgxc43d6DJw2
 o53r+hBTfexVvcCodOREHR253eaw55lnL1J4sn0KVfprd0tLUTtR6QtF6oMXTcRedrE5bbQB
 oH/mmorTeQcEO6uDqc9SgqzEaLpNUxsXOBEMp0HYsQBoTdGzsh6aZGrVHX47A3ZLFv9WbRB+
 iluFb5KY2n673MOZgSuCFurTuNm+Ik4qfHz3KCVkEghN/swYZW/ONxqZC+2kIPO30WJOnvSL
 OptwSrxigmRMwJMCYI59NwaF9lyk/F8iL798mNXuhb9mWoiw2Qfjm5xAI+8u3ECDlF6RImKJ
 QW26frU/JgIUOPrTP+XkxBzCK+vKVekqjhASMH0vLMUBjY02EvqjYfR1egevXc63hMJDR513
 uqyECDvmUMJulfMUR2BeaX/+6/alsvQLlvDF8sZ1wrP4PFdqTELwMPHvKsZgX4KhMnNUhPSD
 XxdTif6ZoOAt/ZdtmdSV6InuwAz/1C9VnBRGP459T4N2OYSql4P4rcGBokrQCFC4kP/ZdqDf
 vnOzfc5OOiR/D+lE
Message-ID: <de7235bc-e458-381d-442e-11b42dd20dc9@gydle.com>
Date:   Mon, 5 Nov 2018 10:12:51 -0500
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.2.1
MIME-Version: 1.0
In-Reply-To: <20181105122610.1555-2-hans.ml.holmberg@owltronix.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 2018-11-05 7:26 a.m., Hans Holmberg wrote:
> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
> 
> Make sure we only look up valid lba addresses on the resubmission path.
> 
> If an lba is invalidated in the write buffer, that sector will be
> submitted to disk(as it is already mapped to a ppa), and that write

submitted to disk(as it is already mapped to a ppa), and that write
                 ^
                 add a space

> might fail, resulting in a crash when trying to look up the lba in the
> mapping table (as the lba is marked as invalid).
> 
> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
> ---
>  drivers/lightnvm/pblk-write.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
> index fa8726493b39..3ddd16f47106 100644
> --- a/drivers/lightnvm/pblk-write.c
> +++ b/drivers/lightnvm/pblk-write.c
> @@ -148,9 +148,11 @@ static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
>  		w_ctx = &entry->w_ctx;
>  
>  		/* Check if the lba has been overwritten */
> -		ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
> -		if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
> -			w_ctx->lba = ADDR_EMPTY;
> +		if (w_ctx->lba != ADDR_EMPTY) {
> +			ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
> +			if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
> +				w_ctx->lba = ADDR_EMPTY;
> +		}

Was w_ctx->lba set to ADDR_EMPTY in the same kernel I/O thread ?

I wonder if w_ctx->lba could become ADDR_EMPTY after 

		if (w_ctx->lba != ADDR_EMPTY) {

but before

			ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);


>  
>  		/* Mark up the entry as submittable again */
>  		flags = READ_ONCE(w_ctx->flags);
>