Subject: FAILED: patch "[PATCH] mtd: spinand: fix NULL pointer dereference with no ECC engine" failed to apply to 6.18-stable tree
To: nuno.sa@analog.com,miquel.raynal@bootlin.com
Cc: <stable@vger.kernel.org>
From: <gregkh@linuxfoundation.org>
Date: Mon, 05 Oct 2026 16:33:20 +0200
Message-ID: <2026100520-premiere-chaps-49ab@gregkh>
Precedence: bulk
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The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x b890e6163761ddb580cc74f43e15f8bbde15647e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026100520-premiere-chaps-49ab@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:


thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b890e6163761ddb580cc74f43e15f8bbde15647e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nuno=20S=C3=A1?= <nuno.sa@analog.com>
Date: Mon, 31 Aug 2026 16:07:17 +0100
Subject: [PATCH] mtd: spinand: fix NULL pointer dereference with no ECC engine
MIME-Version: 1.0
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When "nand-no-ecc-engine" is set in DT, nanddev_get_ecc_engine() takes
the NAND_ECC_ENGINE_TYPE_NONE path and returns success while leaving
nand->ecc.engine NULL. The SPI-NAND code nevertheless dereferences it
unconditionally to test for a pipelined engine, so probing such a
device oopses immediately.

Rather than open-coding the test three times, add a
nand_ecc_is_pipelined() helper to the NAND core that folds the NULL
check into the integration comparison, and use it everywhere. Future
callers then cannot reintroduce the problem.

Fixes: f9d7c7265bcf ("mtd: spinand: Create direct mapping descriptors for ECC operations")
Cc: stable@vger.kernel.org
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

diff --git a/drivers/mtd/nand/ecc.c b/drivers/mtd/nand/ecc.c
index 6ccdff3fc913..1d809cbd47e6 100644
--- a/drivers/mtd/nand/ecc.c
+++ b/drivers/mtd/nand/ecc.c
@@ -159,6 +159,13 @@ int nand_ecc_finish_io_req(struct nand_device *nand,
 }
 EXPORT_SYMBOL(nand_ecc_finish_io_req);
 
+bool nand_ecc_is_pipelined(const struct nand_device *nand)
+{
+	return nand->ecc.engine &&
+	       nand->ecc.engine->integration == NAND_ECC_ENGINE_INTEGRATION_PIPELINED;
+}
+EXPORT_SYMBOL(nand_ecc_is_pipelined);
+
 /* Define default OOB placement schemes for large and small page devices */
 static int nand_ooblayout_ecc_sp(struct mtd_info *mtd, int section,
 				 struct mtd_oob_region *oobregion)
diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index bea352dd82d7..4fb769581595 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -526,8 +526,7 @@ static int spinand_read_from_cache_op(struct spinand_device *spinand,
 	else
 		rdesc->info.op_tmpl = &rdesc->info.primary_op_tmpl;
 
-	if (nand->ecc.engine->integration == NAND_ECC_ENGINE_INTEGRATION_PIPELINED &&
-	    req->mode != MTD_OPS_RAW)
+	if (nand_ecc_is_pipelined(nand) && req->mode != MTD_OPS_RAW)
 		rdesc->info.op_tmpl->data.ecc = true;
 	else
 		rdesc->info.op_tmpl->data.ecc = false;
@@ -621,8 +620,7 @@ static int spinand_write_to_cache_op(struct spinand_device *spinand,
 
 	wdesc = spinand->dirmaps[req->pos.plane].wdesc;
 
-	if (nand->ecc.engine->integration == NAND_ECC_ENGINE_INTEGRATION_PIPELINED &&
-	    req->mode != MTD_OPS_RAW)
+	if (nand_ecc_is_pipelined(nand) && req->mode != MTD_OPS_RAW)
 		wdesc->info.op_tmpl->data.ecc = true;
 	else
 		wdesc->info.op_tmpl->data.ecc = false;
@@ -1279,7 +1277,7 @@ static int spinand_create_dirmap(struct spinand_device *spinand,
 	struct spi_mem_dirmap_desc *desc;
 	bool enable_ecc = false, secondary_op = false;
 
-	if (nand->ecc.engine->integration == NAND_ECC_ENGINE_INTEGRATION_PIPELINED)
+	if (nand_ecc_is_pipelined(nand))
 		enable_ecc = true;
 
 	if (spinand->cont_read_possible && spinand->op_templates->cont_read_cache)
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 09c8c93e4dba..6936180b6ea5 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -305,6 +305,8 @@ int nand_ecc_prepare_io_req(struct nand_device *nand,
 			    struct nand_page_io_req *req);
 int nand_ecc_finish_io_req(struct nand_device *nand,
 			   struct nand_page_io_req *req);
+bool nand_ecc_is_pipelined(const struct nand_device *nand);
+
 bool nand_ecc_is_strong_enough(struct nand_device *nand);
 
 #if IS_REACHABLE(CONFIG_MTD_NAND_CORE)