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From: Keith Busch <kbusch@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>,
	Bart Van Assche <bvanassche@acm.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	linux-nvme@lists.infradead.org, Jens Axboe <axboe@fb.com>,
	Marta Rybczynska <mrybczyn@kalray.eu>,
	Hannes Reinecke <hare@suse.de>, Christoph Hellwig <hch@lst.de>,
	Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH] nvme: fix uninitialized-variable warning
Date: Fri, 14 Feb 2020 04:51:06 +0900	[thread overview]
Message-ID: <20200213195106.GA8256@redsun51.ssa.fujisawa.hgst.com> (raw)
In-Reply-To: <20200130154815.GA2463@infradead.org>

On Thu, Jan 30, 2020 at 07:48:15AM -0800, Christoph Hellwig wrote:
> On Thu, Jan 30, 2020 at 04:36:48PM +0100, Arnd Bergmann wrote:
> > > This one is just gross.  I think we'll need to find some other fix
> > > that doesn't obsfucate the code as much.
> > 
> > Initializing the nvme_result in nvme_features() would do it, as would
> > setting it in the error path in __nvme_submit_sync_cmd() -- either
> > way the compiler cannot be confused about whether it is initialized
> > later on.
> 
> Given that this is outside the hot path we can just zero the whole
> structure before submitting the I/O.

I think this should be okay:

---
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 7f05deada7f4..4aeed750dab2 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1165,8 +1165,8 @@ static int nvme_identify_ns(struct nvme_ctrl *ctrl,
 static int nvme_features(struct nvme_ctrl *dev, u8 op, unsigned int fid,
 		unsigned int dword11, void *buffer, size_t buflen, u32 *result)
 {
+	union nvme_result res = { 0 };
 	struct nvme_command c;
-	union nvme_result res;
 	int ret;
 
 	memset(&c, 0, sizeof(c));
--

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  reply	other threads:[~2020-02-13 19:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-07 21:42 [PATCH] nvme: fix uninitialized-variable warning Arnd Bergmann
2020-01-30 15:04 ` Christoph Hellwig
2020-01-30 15:36   ` Arnd Bergmann
2020-01-30 15:48     ` Christoph Hellwig
2020-02-13 19:51       ` Keith Busch [this message]
2020-02-19 15:21         ` Christoph Hellwig
2020-02-19 16:19 [PATCH] nvme: Fix " Keith Busch
2020-02-19 16:22 ` Christoph Hellwig
2020-02-20  7:43 ` Sagi Grimberg

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