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[v4,00/18] of: overlay: validation checks, subsequent fixes

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Series of: overlay: validation checks, subsequent fixes | expand

Message

Frank Rowand Oct. 16, 2018, 2:37 a.m. UTC
From: Frank Rowand <frank.rowand@sony.com>

Add checks to (1) overlay apply process and (2) memory freeing
triggered by overlay release.  The checks are intended to detect
possible memory leaks and invalid overlays.

The checks revealed bugs in existing code.  Fixed the bugs.

While fixing bugs, noted other issues, which are fixed in
separate patches.

*****  Powerpc folks: I was not able to test the patches that
*****  directly impact Powerpc systems that use dynamic
*****  devicetree.  Please review that code carefully and
*****  test.  The specific patches are: 03/16, 04/16, 07/16

FPGA folks:

  I made the validation checks that should result in an
  invalid live devicetree report "ERROR" and cause the overlay apply
  to fail.

  I made the memory leak validation tests report "WARNING" and allow
  the overlay apply to complete successfully.  Please let me know
  if you encounter the warnings.  There are at least two paths
  forward to deal with the cases that trigger the warning: (1) change
  the warning to an error and fail the overlay apply, or (2) find a
  way to detect the potential memory leaks and free the memory
  appropriately.

ALL people:

  The validations do _not_ address another major concern I have with
  releasing overlays, which is use after free errors.

Changes since v3:
  - 01/18: Add expected value of refcount for destroy cset entry error.  Also
    explain the cause of the error.

  - 09/18: for errors of an overlay changing the value of #size-cells or
    #address-cells, return -EINVAL so that overlay apply will fail
  - 09/18: for errors of an overlay changing the value of #size-cells or
    #address-cells, make the message more direct.
    Old message:
      OF: overlay: ERROR: overlay and/or live tree #size-cells invalid in node /soc/base_fpga_region
    New message:
      OF: overlay: ERROR: changing value of /soc/base_fpga_region/#size-cells not allowed

  - 13/18: Update patch comment header to state that this patch modifies the
    previous patch to not return immediately on fragment error and
    explain this is not a performance issue.
  - 13/18: remove redundant "overlay" from two error messages.  "OF: overlay:"
    is already present in pr_fmt()

Changes since v2:

  - 13/18: Use continue to reduce indentation in find_dup_cset_node_entry()
    and find_dup_cset_prop()

Changes since v1:

  - move patch 16/16 to 17/18
  - move patch 15/16 to 18/18
  - new patch 15/18
  - new patch 16/18

  - 05/18: add_changeset_node() header comment: incorrect comment for @target

  - 18/18: add same fix for of_parse_phandle_with_args()
  - 18/18: add same fix for of_parse_phandle_with_args_map()

Frank Rowand (18):
  of: overlay: add tests to validate kfrees from overlay removal
  of: overlay: add missing of_node_put() after add new node to changeset
  of: overlay: add missing of_node_get() in __of_attach_node_sysfs
  powerpc/pseries: add of_node_put() in dlpar_detach_node()
  of: overlay: use prop add changeset entry for property in new nodes
  of: overlay: do not duplicate properties from overlay for new nodes
  of: dynamic: change type of of_{at,de}tach_node() to void
  of: overlay: reorder fields in struct fragment
  of: overlay: validate overlay properties #address-cells and
    #size-cells
  of: overlay: make all pr_debug() and pr_err() messages unique
  of: overlay: test case of two fragments adding same node
  of: overlay: check prevents multiple fragments add or delete same node
  of: overlay: check prevents multiple fragments touching same property
  of: unittest: remove unused of_unittest_apply_overlay() argument
  of: overlay: set node fields from properties when add new overlay node
  of: unittest: allow base devicetree to have symbol metadata
  of: unittest: find overlays[] entry by name instead of index
  of: unittest: initialize args before calling of_*parse_*()

 arch/powerpc/platforms/pseries/dlpar.c             |  15 +-
 arch/powerpc/platforms/pseries/reconfig.c          |   6 +-
 drivers/of/dynamic.c                               |  68 +++--
 drivers/of/kobj.c                                  |   4 +-
 drivers/of/overlay.c                               | 302 ++++++++++++++++-----
 drivers/of/unittest-data/Makefile                  |   2 +
 .../of/unittest-data/overlay_bad_add_dup_node.dts  |  28 ++
 .../of/unittest-data/overlay_bad_add_dup_prop.dts  |  24 ++
 drivers/of/unittest-data/overlay_base.dts          |   1 +
 drivers/of/unittest.c                              |  96 +++++--
 include/linux/of.h                                 |  19 +-
 11 files changed, 443 insertions(+), 122 deletions(-)
 create mode 100644 drivers/of/unittest-data/overlay_bad_add_dup_node.dts
 create mode 100644 drivers/of/unittest-data/overlay_bad_add_dup_prop.dts

Comments

Michael Ellerman Oct. 16, 2018, 9:47 a.m. UTC | #1
frowand.list@gmail.com writes:

> From: Frank Rowand <frank.rowand@sony.com>
>
> Add checks to (1) overlay apply process and (2) memory freeing
> triggered by overlay release.  The checks are intended to detect
> possible memory leaks and invalid overlays.
>
> The checks revealed bugs in existing code.  Fixed the bugs.
>
> While fixing bugs, noted other issues, which are fixed in
> separate patches.
>
> *****  Powerpc folks: I was not able to test the patches that
> *****  directly impact Powerpc systems that use dynamic
> *****  devicetree.  Please review that code carefully and
> *****  test.  The specific patches are: 03/16, 04/16, 07/16

Hi Frank,

Do you have this series in a git tree somewhere?

I tried applying it on top of linux-next but hit some conflicts which I
couldn't easily resolve.

cheers
Frank Rowand Oct. 17, 2018, 3:08 a.m. UTC | #2
On 10/16/18 02:47, Michael Ellerman wrote:
> frowand.list@gmail.com writes:
> 
>> From: Frank Rowand <frank.rowand@sony.com>
>>
>> Add checks to (1) overlay apply process and (2) memory freeing
>> triggered by overlay release.  The checks are intended to detect
>> possible memory leaks and invalid overlays.
>>
>> The checks revealed bugs in existing code.  Fixed the bugs.
>>
>> While fixing bugs, noted other issues, which are fixed in
>> separate patches.
>>
>> *****  Powerpc folks: I was not able to test the patches that
>> *****  directly impact Powerpc systems that use dynamic
>> *****  devicetree.  Please review that code carefully and
>> *****  test.  The specific patches are: 03/16, 04/16, 07/16
> 
> Hi Frank,
> 
> Do you have this series in a git tree somewhere?
> 
> I tried applying it on top of linux-next but hit some conflicts which I
> couldn't easily resolve.
> 
> cheers
> 



git://git.kernel.org/pub/scm/linux/kernel/git/frowand/linux.git

$ git checkout v4.19-rc1--kfree_validate--v4

$ git log --oneline v4.19-rc1..
2ba1b7d353dd of: unittest: initialize args before calling of_*parse_*()
4f9108209f79 of: unittest: find overlays[] entry by name instead of index
353403c76ff8 of: unittest: allow base devicetree to have symbol metadata
8fc37e04a01b of: overlay: set node fields from properties when add new overlay n
05d5df0e5151 of: unittest: remove unused of_unittest_apply_overlay() argument
8c021cba757a of: overlay: check prevents multiple fragments touching same proper
797a6f66e039 of: overlay: check prevents multiple fragments add or delete same n
c385e25a040d of: overlay: test case of two fragments adding same node
c88fd240f0e0 of: overlay: make all pr_debug() and pr_err() messages unique
1028a215d32a of: overlay: validate overlay properties #address-cells and #size-c
f1a97ef74ce4 of: overlay: reorder fields in struct fragment
ffe78cf7a1fb of: dynamic: change type of of_{at,de}tach_node() to void
5f5ff8ec0c0c of: overlay: do not duplicate properties from overlay for new nodes
06e72dcb2bb0 of: overlay: use prop add changeset entry for property in new nodes
a02f8d326a08 powerpc/pseries: add of_node_put() in dlpar_detach_node()
e203be664330 of: overlay: add missing of_node_get() in __of_attach_node_sysfs
8eb46208e7c8 of: overlay: add missing of_node_put() after add new node to change
b22067db7cf9 of: overlay: add tests to validate kfrees from overlay removal
Alan Tull Oct. 17, 2018, 9:16 p.m. UTC | #3
On Tue, Oct 16, 2018 at 10:08 PM Frank Rowand <frowand.list@gmail.com> wrote:
>
> On 10/16/18 02:47, Michael Ellerman wrote:
> > frowand.list@gmail.com writes:
> >
> >> From: Frank Rowand <frank.rowand@sony.com>
> >>
> >> Add checks to (1) overlay apply process and (2) memory freeing
> >> triggered by overlay release.  The checks are intended to detect
> >> possible memory leaks and invalid overlays.
> >>
> >> The checks revealed bugs in existing code.  Fixed the bugs.
> >>
> >> While fixing bugs, noted other issues, which are fixed in
> >> separate patches.
> >>
> >> *****  Powerpc folks: I was not able to test the patches that
> >> *****  directly impact Powerpc systems that use dynamic
> >> *****  devicetree.  Please review that code carefully and
> >> *****  test.  The specific patches are: 03/16, 04/16, 07/16
> >
> > Hi Frank,
> >
> > Do you have this series in a git tree somewhere?
> >
> > I tried applying it on top of linux-next but hit some conflicts which I
> > couldn't easily resolve.
> >
> > cheers
> >
>
>
>
> git://git.kernel.org/pub/scm/linux/kernel/git/frowand/linux.git
>
> $ git checkout v4.19-rc1--kfree_validate--v4
>
> $ git log --oneline v4.19-rc1..
> 2ba1b7d353dd of: unittest: initialize args before calling of_*parse_*()
> 4f9108209f79 of: unittest: find overlays[] entry by name instead of index
> 353403c76ff8 of: unittest: allow base devicetree to have symbol metadata
> 8fc37e04a01b of: overlay: set node fields from properties when add new overlay n
> 05d5df0e5151 of: unittest: remove unused of_unittest_apply_overlay() argument
> 8c021cba757a of: overlay: check prevents multiple fragments touching same proper
> 797a6f66e039 of: overlay: check prevents multiple fragments add or delete same n
> c385e25a040d of: overlay: test case of two fragments adding same node
> c88fd240f0e0 of: overlay: make all pr_debug() and pr_err() messages unique
> 1028a215d32a of: overlay: validate overlay properties #address-cells and #size-c
> f1a97ef74ce4 of: overlay: reorder fields in struct fragment
> ffe78cf7a1fb of: dynamic: change type of of_{at,de}tach_node() to void
> 5f5ff8ec0c0c of: overlay: do not duplicate properties from overlay for new nodes
> 06e72dcb2bb0 of: overlay: use prop add changeset entry for property in new nodes
> a02f8d326a08 powerpc/pseries: add of_node_put() in dlpar_detach_node()
> e203be664330 of: overlay: add missing of_node_get() in __of_attach_node_sysfs
> 8eb46208e7c8 of: overlay: add missing of_node_put() after add new node to change
> b22067db7cf9 of: overlay: add tests to validate kfrees from overlay removal

That branch is a real time saver, thanks!

ALan