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Message-ID: <CANk1AXRmF8ANrz-aBcmbYA_uJM-iEX7vbGWONFbr5pQBa_9VEQ@mail.gmail.com>
Date: Mon, 15 Oct 2018 15:47:28 -0500
From: Alan Tull <atull@...nel.org>
To: Frank Rowand <frowand.list@...il.com>
Cc: Rob Herring <robh+dt@...nel.org>,
Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Moritz Fischer <mdf@...nel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>, linux-fpga@...r.kernel.org
Subject: Re: [PATCH v3 00/18] of: overlay: validation checks, subsequent fixes
On Mon, Oct 15, 2018 at 3:24 PM Frank Rowand <frowand.list@...il.com> wrote:
>
> On 10/15/18 12:21, Alan Tull wrote:
> > On Sun, Oct 14, 2018 at 7:26 PM <frowand.list@...il.com> wrote:
> >>
> >> From: Frank Rowand <frank.rowand@...y.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
>
> Thanks for the further testing!
>
>
> > 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@...ia10:~# ./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@...ia10:~# ./apply-static-region.sh root@...ia10:~# 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
>
> That is indicating that an unbalanced of_node_get() / of_node_put()
> exists for that node. I'll have to update that message to be more
> explicit about that.
Yes, that sounds good
>
> -Frank
>
> >
> > 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@...y.com>
> >>
> >
>
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