[PATCH 6.1 FIX] mtd: core: add missing of_node_get() in dynamic partitions code

[Miquel Raynal]

On Tue, 2022-10-18 at 05:18:22 UTC, =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= wrote:
> From: Rafał Miłecki <rafal at milecki.pl>
> 
> 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 at nxp.com>
> Fixes: ad9b10d1eaada169 ("mtd: core: introduce of support for dynamic partitions")
> Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
> Tested-by: Han Xu <han.xu at nxp.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/fixes, thanks.

Miquel