[PATCH v2] of: __of_update_property_sysfs only call __of_sysfs_remove_bin_file if of_node_is_attached

Hi Rob,

I have used an other hardware to check the patch. I hope it doesn’t matter. I added few lines at the untitest.c. All existing unittest use an attached sysfs, therefore the bug isn't detectable.

Best regards
Andre Kalb

quoted hunk

On Thu, Sep 13, 2018 at 4:42 PM Andre Kalb [off-list ref] wrote:
From 1e86e351efa1a7cea31d157bafb0ae40b856cdcc Mon Sep 17 00:00:00
2001
From: Andre Kalb <redacted>
Date: Thu, 13 Sep 2018 16:42:48 +0200
Subject: [PATCH] Added new unittest

---
 drivers/of/unittest.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c index

2a547ca3d443..17f6cacb4fae 100644

--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c

@@ -923,6 +923,24 @@ static int __init unittest_data_add(void)
              return -EINVAL;
      }

+     {
+             struct property *prop;
+
+             prop = kzalloc(sizeof(*prop), GFP_KERNEL);
+             if (!prop) {
+                     unittest(0, "kzalloc() failed\n");
+                     return -ENOMEM;
+             }
+
+             np = of_find_node_with_property(unittest_data_node, "prop-

update");
+             unittest(np, "find prop-update");
+
+             prop->name = "prop-update";
+             prop->value = "new-property-data";
+             prop->length = strlen(prop->value) + 1;
+             unittest(of_update_property(np, prop) == 0, "Update a existing
property failed\n");
+     }
+
      if (!of_root) {
              of_root = unittest_data_node;
              for_each_of_allnodes(np)
--
2.16.4

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at fs/kernfs/dir.c:1481 kernfs_remove_by_name_ns+0x9c/0xa4
kernfs: can not remove '(null)', no directory
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.18.7 #3
Hardware name: Freescale i.MX6 Ultralite (Device Tree)
[<c010f338>] (unwind_backtrace) from [<c010cefc>] (show_stack+0x10/0x14)
[<c010cefc>] (show_stack) from [<c0122004>] (__warn+0xe0/0xf8)
[<c0122004>] (__warn) from [<c0122060>] (warn_slowpath_fmt+0x44/0x68)
[<c0122060>] (warn_slowpath_fmt) from [<c02c6540>] (kernfs_remove_by_name_ns+0x9c/0xa4)
[<c02c6540>] (kernfs_remove_by_name_ns) from [<c055a704>] (__of_update_property_sysfs+0x38/0x50)
[<c055a704>] (__of_update_property_sysfs) from [<c0557b94>] (of_update_property+0xc0/0x104)
[<c0557b94>] (of_update_property) from [<c09521bc>] (of_unittest+0x1b8/0x28d4)
[<c09521bc>] (of_unittest) from [<c0102d88>] (do_one_initcall+0x40/0x218)
[<c0102d88>] (do_one_initcall) from [<c090101c>] (kernel_init_freeable+0x24c/0x2e4)
[<c090101c>] (kernel_init_freeable) from [<c06a1f6c>] (kernel_init+0x8/0x110)
[<c06a1f6c>] (kernel_init) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
Exception stack(0xcc099fb0 to 0xcc099ff8)
9fa0:                                     00000000 00000000 00000000 00000000
9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
---[ end trace 4522f69e0760e4d5 ]---

-----Ursprüngliche Nachricht-----
Von: Rob Herring [mailto:robh+dt@kernel.org]
Gesendet: Montag, 10. September 2018 15:47
An: Andre Kalb
Cc: Frank Rowand; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org
Betreff: Re: [PATCH v2] of: __of_update_property_sysfs only call
__of_sysfs_remove_bin_file if of_node_is_attached

On Mon, Sep 10, 2018 at 4:51 AM Andre Kalb [off-list ref] wrote:

quoted

Hi Frank,

quoted

-----Ursprüngliche Nachricht-----
Von: Frank Rowand [mailto:frowand.list@gmail.com]
Gesendet: Freitag, 7. September 2018 22:01
An: Andre Kalb; robh+dt@kernel.org; devicetree@vger.kernel.org;
linux- kernel@vger.kernel.org
Betreff: Re: [PATCH v2] of: __of_update_property_sysfs only call
__of_sysfs_remove_bin_file if of_node_is_attached

Hi Andred,

On 09/04/18 08:51, Andre Kalb wrote:

quoted

To prevent warning "kernfs: can not remove '(null)', no directory"
if an overlay

isn't applied to the active devicetree.

quoted

Using of_remove_property and then of_add_property doesn't show the

warning.

[...]

quoted

quoted

What is the calling path that results in the warning?

-Frank

There is the callstack of the warning.

[   10.782830] ------------[ cut here ]------------
[   10.830357] WARNING: CPU: 0 PID: 170 at /linux-4.x/fs/kernfs/dir.c:1276

kernfs_remove_by_name_ns+0x30/0x80()

quoted

[   10.928997] kernfs: can not remove '(null)', no directory
[   10.993107] Modules linked in: module_capemgr(+)
[   11.045750] CPU: 0 PID: 170 Comm: systemd-udevd Not tainted 4.4.143-

00158-g8e5ca65ec7ee-dirty #114

158 patches on top of an almost 3 year old kernel...

quoted

[   12.011373] [<bf0000e4>] (module_capemgr_slot_scan [module_capemgr])

from [<bf0007bc>] (module_capemgr_probe+0x3c/0x58 [module_capemgr])

And a driver that's not upstream.

Not saying the fix isn't valid, but please reproduce on recent mainline. Add a
unittest if you have to.

Rob

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