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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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