kernel: mtd: fix unbalanced of_node_put() in dynamic partitions code

Fixes: cae4d089bc1d3 ("kernel: backport mtd dynamic partition patch")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit 76a470d5df971bd4c7309480a585d7fbaef63621)

diff --git a/target/linux/generic/backport-5.10/416-v6.1-mtd-core-add-missing-of_node_get-in-dynamic-partitio.patch b/target/linux/generic/backport-5.10/416-v6.1-mtd-core-add-missing-of_node_get-in-dynamic-partitio.patch
new file mode 100644 (file)
index 0000000..0c359c6
--- /dev/null
+++ b/target/linux/generic/backport-5.10/416-v6.1-mtd-core-add-missing-of_node_get-in-dynamic-partitio.patch
@@ -0,0 +1,101 @@
+From 12b58961de0bd88b3c7dfa5d21f6d67f4678b780 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Tue, 18 Oct 2022 07:18:22 +0200
+Subject: [PATCH] mtd: core: add missing of_node_get() in dynamic partitions
+ code
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This fixes unbalanced of_node_put():
+[    1.078910] 6 cmdlinepart partitions found on MTD device gpmi-nand
+[    1.085116] Creating 6 MTD partitions on "gpmi-nand":
+[    1.090181] 0x000000000000-0x000008000000 : "nandboot"
+[    1.096952] 0x000008000000-0x000009000000 : "nandfit"
+[    1.103547] 0x000009000000-0x00000b000000 : "nandkernel"
+[    1.110317] 0x00000b000000-0x00000c000000 : "nanddtb"
+[    1.115525] ------------[ cut here ]------------
+[    1.120141] refcount_t: addition on 0; use-after-free.
+[    1.125328] WARNING: CPU: 0 PID: 1 at lib/refcount.c:25 refcount_warn_saturate+0xdc/0x148
+[    1.133528] Modules linked in:
+[    1.136589] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.0.0-rc7-next-20220930-04543-g8cf3f7
+[    1.146342] Hardware name: Freescale i.MX8DXL DDR3L EVK (DT)
+[    1.151999] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
+[    1.158965] pc : refcount_warn_saturate+0xdc/0x148
+[    1.163760] lr : refcount_warn_saturate+0xdc/0x148
+[    1.168556] sp : ffff800009ddb080
+[    1.171866] x29: ffff800009ddb080 x28: ffff800009ddb35a x27: 0000000000000002
+[    1.179015] x26: ffff8000098b06ad x25: ffffffffffffffff x24: ffff0a00ffffff05
+[    1.186165] x23: ffff00001fdf6470 x22: ffff800009ddb367 x21: 0000000000000000
+[    1.193314] x20: ffff00001fdfebe8 x19: ffff00001fdfec50 x18: ffffffffffffffff
+[    1.200464] x17: 0000000000000000 x16: 0000000000000118 x15: 0000000000000004
+[    1.207614] x14: 0000000000000fff x13: ffff800009bca248 x12: 0000000000000003
+[    1.214764] x11: 00000000ffffefff x10: c0000000ffffefff x9 : 4762cb2ccb52de00
+[    1.221914] x8 : 4762cb2ccb52de00 x7 : 205d313431303231 x6 : 312e31202020205b
+[    1.229063] x5 : ffff800009d55c1f x4 : 0000000000000001 x3 : 0000000000000000
+[    1.236213] x2 : 0000000000000000 x1 : ffff800009954be6 x0 : 000000000000002a
+[    1.243365] Call trace:
+[    1.245806]  refcount_warn_saturate+0xdc/0x148
+[    1.250253]  kobject_get+0x98/0x9c
+[    1.253658]  of_node_get+0x20/0x34
+[    1.257072]  of_fwnode_get+0x3c/0x54
+[    1.260652]  fwnode_get_nth_parent+0xd8/0xf4
+[    1.264926]  fwnode_full_name_string+0x3c/0xb4
+[    1.269373]  device_node_string+0x498/0x5b4
+[    1.273561]  pointer+0x41c/0x5d0
+[    1.276793]  vsnprintf+0x4d8/0x694
+[    1.280198]  vprintk_store+0x164/0x528
+[    1.283951]  vprintk_emit+0x98/0x164
+[    1.287530]  vprintk_default+0x44/0x6c
+[    1.291284]  vprintk+0xf0/0x134
+[    1.294428]  _printk+0x54/0x7c
+[    1.297486]  of_node_release+0xe8/0x128
+[    1.301326]  kobject_put+0x98/0xfc
+[    1.304732]  of_node_put+0x1c/0x28
+[    1.308137]  add_mtd_device+0x484/0x6d4
+[    1.311977]  add_mtd_partitions+0xf0/0x1d0
+[    1.316078]  parse_mtd_partitions+0x45c/0x518
+[    1.320439]  mtd_device_parse_register+0xb0/0x274
+[    1.325147]  gpmi_nand_probe+0x51c/0x650
+[    1.329074]  platform_probe+0xa8/0xd0
+[    1.332740]  really_probe+0x130/0x334
+[    1.336406]  __driver_probe_device+0xb4/0xe0
+[    1.340681]  driver_probe_device+0x3c/0x1f8
+[    1.344869]  __driver_attach+0xdc/0x1a4
+[    1.348708]  bus_for_each_dev+0x80/0xcc
+[    1.352548]  driver_attach+0x24/0x30
+[    1.356127]  bus_add_driver+0x108/0x1f4
+[    1.359967]  driver_register+0x78/0x114
+[    1.363807]  __platform_driver_register+0x24/0x30
+[    1.368515]  gpmi_nand_driver_init+0x1c/0x28
+[    1.372798]  do_one_initcall+0xbc/0x238
+[    1.376638]  do_initcall_level+0x94/0xb4
+[    1.380565]  do_initcalls+0x54/0x94
+[    1.384058]  do_basic_setup+0x1c/0x28
+[    1.387724]  kernel_init_freeable+0x110/0x188
+[    1.392084]  kernel_init+0x20/0x1a0
+[    1.395578]  ret_from_fork+0x10/0x20
+[    1.399157] ---[ end trace 0000000000000000 ]---
+[    1.403782] ------------[ cut here ]------------
+
+Reported-by: Han Xu <han.xu@nxp.com>
+Fixes: ad9b10d1eaada169 ("mtd: core: introduce of support for dynamic partitions")
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Tested-by: Han Xu <han.xu@nxp.com>
+Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
+Link: https://lore.kernel.org/linux-mtd/20221018051822.28685-1-zajec5@gmail.com
+---
+ drivers/mtd/mtdcore.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/mtd/mtdcore.c
++++ b/drivers/mtd/mtdcore.c
+@@ -577,7 +577,7 @@ static void mtd_check_of_node(struct mtd
+       if (!mtd_is_partition(mtd))
+               return;
+       parent = mtd->parent;
+-      parent_dn = dev_of_node(&parent->dev);
++      parent_dn = of_node_get(dev_of_node(&parent->dev));
+       if (!parent_dn)
+               return;
+