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From: Arnd Bergmann <arnd@arndb.de>
To: linux-kernel@vger.kernel.org,
	James Smart <james.smart@broadcom.com>,
	Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	Israel Rukshin <israelr@mellanox.com>,
	Max Gurtovoy <maxg@mellanox.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Ming Lei <ming.lei@redhat.com>,
	Hannes Reinecke <hare@suse.de>,
	linux-nvme@lists.infradead.org
Subject: [PATCH 15/15] nvme: avoid gcc-10 zero-length-bounds warning
Date: Thu, 30 Apr 2020 23:30:57 +0200	[thread overview]
Message-ID: <20200430213101.135134-16-arnd@arndb.de> (raw)
In-Reply-To: <20200430213101.135134-1-arnd@arndb.de>

When CONFIG_ARCH_NO_SG_CHAIN is set, op->sgl[0] cannot be dereferenced,
as gcc-10 now points out:

drivers/nvme/host/fc.c: In function 'nvme_fc_init_request':
drivers/nvme/host/fc.c:1774:29: warning: array subscript 0 is outside the bounds of an interior zero-length array 'struct scatterlist[0]' [-Wzero-length-bounds]
 1774 |  op->op.fcp_req.first_sgl = &op->sgl[0];
      |                             ^~~~~~~~~~~
drivers/nvme/host/fc.c:98:21: note: while referencing 'sgl'
   98 |  struct scatterlist sgl[NVME_INLINE_SG_CNT];
      |                     ^~~

I don't know if this is a legitimate warning or a false-positive.
If this is just a false alarm, the warning is easily suppressed
by interpreting the array as a pointer.

Fixes: b1ae1a238900 ("nvme-fc: Avoid preallocating big SGL for data")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/nvme/host/fc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 887537d1243f..b7ecda48d597 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -1771,7 +1771,7 @@ nvme_fc_init_request(struct blk_mq_tag_set *set, struct request *rq,
 	res = __nvme_fc_init_request(ctrl, queue, &op->op, rq, queue->rqcnt++);
 	if (res)
 		return res;
-	op->op.fcp_req.first_sgl = &op->sgl[0];
+	op->op.fcp_req.first_sgl = op->sgl;
 	op->op.fcp_req.private = &op->priv[0];
 	nvme_req(rq)->ctrl = &ctrl->ctrl;
 	return res;
-- 
2.26.0


WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: linux-kernel@vger.kernel.org,
	James Smart <james.smart@broadcom.com>,
	Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	Israel Rukshin <israelr@mellanox.com>,
	Max Gurtovoy <maxg@mellanox.com>
Cc: linux-nvme@lists.infradead.org, Hannes Reinecke <hare@suse.de>,
	Arnd Bergmann <arnd@arndb.de>, Ming Lei <ming.lei@redhat.com>
Subject: [PATCH 15/15] nvme: avoid gcc-10 zero-length-bounds warning
Date: Thu, 30 Apr 2020 23:30:57 +0200	[thread overview]
Message-ID: <20200430213101.135134-16-arnd@arndb.de> (raw)
In-Reply-To: <20200430213101.135134-1-arnd@arndb.de>

When CONFIG_ARCH_NO_SG_CHAIN is set, op->sgl[0] cannot be dereferenced,
as gcc-10 now points out:

drivers/nvme/host/fc.c: In function 'nvme_fc_init_request':
drivers/nvme/host/fc.c:1774:29: warning: array subscript 0 is outside the bounds of an interior zero-length array 'struct scatterlist[0]' [-Wzero-length-bounds]
 1774 |  op->op.fcp_req.first_sgl = &op->sgl[0];
      |                             ^~~~~~~~~~~
drivers/nvme/host/fc.c:98:21: note: while referencing 'sgl'
   98 |  struct scatterlist sgl[NVME_INLINE_SG_CNT];
      |                     ^~~

I don't know if this is a legitimate warning or a false-positive.
If this is just a false alarm, the warning is easily suppressed
by interpreting the array as a pointer.

Fixes: b1ae1a238900 ("nvme-fc: Avoid preallocating big SGL for data")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/nvme/host/fc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 887537d1243f..b7ecda48d597 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -1771,7 +1771,7 @@ nvme_fc_init_request(struct blk_mq_tag_set *set, struct request *rq,
 	res = __nvme_fc_init_request(ctrl, queue, &op->op, rq, queue->rqcnt++);
 	if (res)
 		return res;
-	op->op.fcp_req.first_sgl = &op->sgl[0];
+	op->op.fcp_req.first_sgl = op->sgl;
 	op->op.fcp_req.private = &op->priv[0];
 	nvme_req(rq)->ctrl = &ctrl->ctrl;
 	return res;
-- 
2.26.0


_______________________________________________
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linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  parent reply	other threads:[~2020-04-30 21:34 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30 21:30 [PATCH 00/15] gcc-10 warning fixes Arnd Bergmann
2020-04-30 21:30 ` Arnd Bergmann
2020-04-30 21:30 ` Arnd Bergmann
2020-04-30 21:30 ` [PATCH 01/15] crypto - Avoid free() namespace collision Arnd Bergmann
2020-05-08  6:06   ` Herbert Xu
2020-04-30 21:30 ` [PATCH 02/15] iwlwifi: mvm: fix gcc-10 zero-length-bounds warning Arnd Bergmann
2020-06-10 12:18   ` Luciano Coelho
2020-04-30 21:30 ` [PATCH 03/15] mwifiex: avoid -Wstringop-overflow warning Arnd Bergmann
2020-05-06  8:43   ` Kalle Valo
2020-04-30 21:30 ` [PATCH 04/15] ath10k: fix gcc-10 zero-length-bounds warnings Arnd Bergmann
2020-04-30 21:30   ` Arnd Bergmann
2020-04-30 21:45   ` Gustavo A. R. Silva
2020-04-30 21:45     ` Gustavo A. R. Silva
2020-04-30 21:44     ` Arnd Bergmann
2020-04-30 21:44       ` Arnd Bergmann
2020-05-04 11:54     ` Kalle Valo
2020-05-04 11:54       ` Kalle Valo
2020-05-04 16:09       ` Gustavo A. R. Silva
2020-05-04 16:09         ` Gustavo A. R. Silva
2020-05-05  4:56         ` Kalle Valo
2020-05-05  4:56           ` Kalle Valo
2020-04-30 21:30 ` [PATCH 05/15] bpf: avoid gcc-10 stringop-overflow warning Arnd Bergmann
2020-05-04 21:06   ` Daniel Borkmann
2020-04-30 21:30 ` [PATCH 06/15] netfilter: conntrack: avoid gcc-10 zero-length-bounds warning Arnd Bergmann
2020-05-10 21:48   ` Pablo Neira Ayuso
2020-04-30 21:30 ` [PATCH 07/15] drop_monitor: work around gcc-10 stringop-overflow warning Arnd Bergmann
2020-05-01 11:28   ` Neil Horman
2020-04-30 21:30 ` [PATCH 08/15] usb: ehci: avoid gcc-10 zero-length-bounds warning Arnd Bergmann
2020-05-01  2:42   ` Alan Stern
2020-05-01 20:06     ` Arnd Bergmann
2020-05-01 20:10       ` Alan Stern
2020-04-30 21:30 ` [PATCH 09/15] udf: avoid gcc-10 zero-length-bounds warnings Arnd Bergmann
2020-04-30 21:54   ` Pali Rohár
2020-05-01 20:30     ` Arnd Bergmann
2020-05-01 20:48       ` Jan Kara
2020-05-01 20:57       ` Pali Rohár
2020-04-30 21:30 ` [PATCH 10/15] hpfs: avoid gcc-10 zero-length-bounds warning Arnd Bergmann
2020-04-30 21:30 ` [PATCH 11/15] omfs: avoid gcc-10 stringop-overflow warning Arnd Bergmann
2020-04-30 21:30 ` [PATCH 12/15] media: s5k5baf: avoid gcc-10 zero-length-bounds warning Arnd Bergmann
2020-04-30 21:46   ` Gustavo A. R. Silva
2020-04-30 21:30 ` [PATCH 13/15] scsi: sas: " Arnd Bergmann
2020-05-01  7:47   ` John Garry
2020-05-01  7:54     ` Arnd Bergmann
2020-05-01 14:53       ` James Bottomley
2020-05-01 17:36         ` Arnd Bergmann
2020-04-30 21:30 ` [PATCH 14/15] isci: " Arnd Bergmann
2020-04-30 21:30 ` Arnd Bergmann [this message]
2020-04-30 21:30   ` [PATCH 15/15] nvme: " Arnd Bergmann
2020-05-01  7:32   ` Christoph Hellwig
2020-05-01  7:32     ` Christoph Hellwig

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