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SubjectRe: [PATCH v3 00/18] of: overlay: validation checks, subsequent fixes
On Sun, Oct 14, 2018 at 7:26 PM <frowand.list@gmail.com> wrote:
>
> 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.

I reran my FPGA testing. The strings are fixed, no longer NULL. I
have functionality back, my test passes now. I'm seeing the intended
warnings about any properties added to existing nodes. That includes
warnings about added symbols. Below is a simplified part to show some
of what I'm seeing.

By the way my testing is all using Pantelis' DT overlay configfs interface.

root@arria10:~# ./apply-static-region.sh

Applying dtbo: socfpga_arria10_socdk_sdmmc_ghrd_ovl_ext_cfg.dtb

[ 1821.088640] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property:
/soc/base_fpga_region/ranges
[ 1821.103307] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property:
/soc/base_fpga_region/external-fpga-config
[ 1821.117359] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property:
/soc/base_fpga_region/clocks
[ 1821.130130] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property:
/soc/base_fpga_region/clock-names
[ 1821.143449] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property: /__symbols__/clk_0
[ 1821.155357] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property: /__symbols__/ILC
[ 1821.167074] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property:
/__symbols__/freeze_controller_0
[ 1821.180171] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property:
/__symbols__/sysid_qsys_0
[ 1821.192662] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property: /__symbols__/led_pio
[ 1821.204720] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property: /__symbols__/button_pio
[ 1821.217034] OF: overlay: WARNING: add_changeset_property(), memory
leak will occur if overlay removed. Property: /__symbols__/dipsw_pio
[ 1821.231977] of-fpga-region soc:base_fpga_region:fpga_pr_region0:
FPGA Region probed
[ 1821.240144] altera_freeze_br ff200450.freeze_controller: fpga
bridge [freeze] registered

root@arria10:~# ./apply-static-region.sh root@arria10:~# rmdir
/sys/kernel/config/device-tree/overlays/1-socfpga_arria10_socdk_sdmmc_ghrd_ovl_ext_cfg.dtb

[ 1823.805564] OF: ERROR: memory leak - destroy cset entry: attach
overlay node /soc/base_fpga_region/clk_0 with refcount 2

Alan


Alan



>
> ALL people:
>
> The validations do _not_ address another major concern I have with
> releasing overlays, which is use after free errors.
>
> 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 | 298 ++++++++++++++++-----
> 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, 439 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
>
> --
> Frank Rowand <frank.rowand@sony.com>
>

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