From: Rob Herring <robh@kernel.org>
To: frowand.list@gmail.com
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>, Alan Tull <atull@kernel.org>,
Moritz Fischer <mdf@kernel.org>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
devicetree@vger.kernel.org, linux-fpga@vger.kernel.org
Subject: Re: [PATCH v4 01/18] of: overlay: add tests to validate kfrees from overlay removal
Date: Thu, 18 Oct 2018 12:03:03 -0500 [thread overview]
Message-ID: <20181018170303.GA15557@bogus> (raw)
In-Reply-To: <1539657458-24401-2-git-send-email-frowand.list@gmail.com>
On Mon, Oct 15, 2018 at 07:37:21PM -0700, frowand.list@gmail.com wrote:
> From: Frank Rowand <frank.rowand@sony.com>
>
> Add checks:
> - attempted kfree due to refcount reaching zero before overlay
> is removed
> - properties linked to an overlay node when the node is removed
> - node refcount > one during node removal in a changeset destroy,
> if the node was created by the changeset
>
> After applying this patch, several validation warnings will be
> reported from the devicetree unittest during boot due to
> pre-existing devicetree bugs. The warnings will be similar to:
>
> OF: ERROR: of_node_release() overlay node /testcase-data/overlay-node/test-bus/test-unittest11/test-unittest111 contains unexpected properties
> OF: ERROR: memory leak - destroy cset entry: attach overlay node /testcase-data-2/substation@100/hvac-medium-2 expected refcount 1 instead of 2. of_node_get() / of_node_put() are unbalanced for this node.
These messages could be formatted more consistently. Put the path either
at the beginning (after any prefix) or end. Beginning is more like a
compiler error. End puts what the problem is before it's off the edge of
the screen.
> Signed-off-by: Frank Rowand <frank.rowand@sony.com>
> ---
> Changes since v3:
> - Add expected value of refcount for destroy cset entry error. Also
> explain the cause of the error.
>
> drivers/of/dynamic.c | 29 +++++++++++++++++++++++++++++
> drivers/of/overlay.c | 1 +
> include/linux/of.h | 15 ++++++++++-----
> 3 files changed, 40 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
> index f4f8ed9b5454..24c97b7a050f 100644
> --- a/drivers/of/dynamic.c
> +++ b/drivers/of/dynamic.c
> @@ -330,6 +330,25 @@ void of_node_release(struct kobject *kobj)
> if (!of_node_check_flag(node, OF_DYNAMIC))
> return;
>
> + if (of_node_check_flag(node, OF_OVERLAY)) {
> +
> + if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
I worry the flags are getting unwieldy.
> + /* premature refcount of zero, do not free memory */
> + pr_err("ERROR: memory leak %s() overlay node %pOF before free overlay changeset\n",
> + __func__, node);
> + return;
> + }
> +
> + /*
> + * If node->properties non-empty then properties were added
> + * to this node either by different overlay that has not
> + * yet been removed, or by a non-overlay mechanism.
> + */
> + if (node->properties)
> + pr_err("ERROR: %s() overlay node %pOF contains unexpected properties\n",
> + __func__, node);
> + }
> +
> property_list_free(node->properties);
> property_list_free(node->deadprops);
>
> @@ -434,6 +453,16 @@ struct device_node *__of_node_dup(const struct device_node *np,
>
> static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
> {
> + if (ce->action == OF_RECONFIG_ATTACH_NODE &&
> + of_node_check_flag(ce->np, OF_OVERLAY)) {
> + if (kref_read(&ce->np->kobj.kref) > 1) {
> + pr_err("ERROR: memory leak - destroy cset entry: attach overlay node %pOF expected refcount 1 instead of %d. of_node_get() / of_node_put() are unbalanced for this node.\n",
> + ce->np, kref_read(&ce->np->kobj.kref));
> + } else {
> + of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
> + }
> + }
> +
> of_node_put(ce->np);
> list_del(&ce->node);
> kfree(ce);
> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> index eda57ef12fd0..1176cb4b6e4e 100644
> --- a/drivers/of/overlay.c
> +++ b/drivers/of/overlay.c
> @@ -373,6 +373,7 @@ static int add_changeset_node(struct overlay_changeset *ovcs,
> return -ENOMEM;
>
> tchild->parent = target_node;
> + of_node_set_flag(tchild, OF_OVERLAY);
>
> ret = of_changeset_attach_node(&ovcs->cset, tchild);
> if (ret)
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 4d25e4f952d9..aa1dafaec6ae 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -138,11 +138,16 @@ static inline void of_node_put(struct device_node *node) { }
> extern struct device_node *of_stdout;
> extern raw_spinlock_t devtree_lock;
>
> -/* flag descriptions (need to be visible even when !CONFIG_OF) */
> -#define OF_DYNAMIC 1 /* node and properties were allocated via kmalloc */
> -#define OF_DETACHED 2 /* node has been detached from the device tree */
> -#define OF_POPULATED 3 /* device already created for the node */
> -#define OF_POPULATED_BUS 4 /* of_platform_populate recursed to children of this node */
> +/*
> + * struct device_node flag descriptions
> + * (need to be visible even when !CONFIG_OF)
> + */
> +#define OF_DYNAMIC 1 /* (and properties) allocated via kmalloc */
> +#define OF_DETACHED 2 /* detached from the device tree */
> +#define OF_POPULATED 3 /* device already created */
> +#define OF_POPULATED_BUS 4 /* platform bus created for children */
> +#define OF_OVERLAY 5 /* allocated for an overlay */
> +#define OF_OVERLAY_FREE_CSET 6 /* in overlay cset being freed */
>
> #define OF_BAD_ADDR ((u64)-1)
>
> --
> Frank Rowand <frank.rowand@sony.com>
>
next prev parent reply other threads:[~2018-10-18 17:03 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-16 2:37 [PATCH v4 00/18] of: overlay: validation checks, subsequent fixes frowand.list
2018-10-16 2:37 ` [PATCH v4 01/18] of: overlay: add tests to validate kfrees from overlay removal frowand.list
2018-10-17 21:30 ` Alan Tull
2018-10-18 20:24 ` Alan Tull
2018-10-18 17:03 ` Rob Herring [this message]
2018-10-18 19:01 ` Frank Rowand
2018-10-16 2:37 ` [PATCH v4 02/18] of: overlay: add missing of_node_put() after add new node to changeset frowand.list
2018-10-18 17:05 ` Rob Herring
2018-10-18 19:02 ` Frank Rowand
2018-10-16 2:37 ` [PATCH v4 03/18] of: overlay: add missing of_node_get() in __of_attach_node_sysfs frowand.list
2018-10-16 2:37 ` [PATCH v4 04/18] powerpc/pseries: add of_node_put() in dlpar_detach_node() frowand.list
2018-10-18 17:09 ` Rob Herring
2018-10-18 19:09 ` Frank Rowand
2018-10-19 16:10 ` Rob Herring
2018-10-16 2:37 ` [PATCH v4 05/18] of: overlay: use prop add changeset entry for property in new nodes frowand.list
2018-10-16 2:37 ` [PATCH v4 06/18] of: overlay: do not duplicate properties from overlay for " frowand.list
2018-10-16 2:37 ` [PATCH v4 07/18] of: dynamic: change type of of_{at,de}tach_node() to void frowand.list
2018-10-16 2:37 ` [PATCH v4 08/18] of: overlay: reorder fields in struct fragment frowand.list
2018-10-16 2:37 ` [PATCH v4 09/18] of: overlay: validate overlay properties #address-cells and #size-cells frowand.list
2018-10-18 18:13 ` Rob Herring
2018-10-18 19:13 ` Frank Rowand
2018-10-16 2:37 ` [PATCH v4 10/18] of: overlay: make all pr_debug() and pr_err() messages unique frowand.list
2018-10-16 2:37 ` [PATCH v4 11/18] of: overlay: test case of two fragments adding same node frowand.list
2018-10-16 2:37 ` [PATCH v4 12/18] of: overlay: check prevents multiple fragments add or delete " frowand.list
2018-10-16 2:37 ` [PATCH v4 13/18] of: overlay: check prevents multiple fragments touching same property frowand.list
2018-10-16 2:37 ` [PATCH v4 14/18] of: unittest: remove unused of_unittest_apply_overlay() argument frowand.list
2018-10-16 2:37 ` [PATCH v4 15/18] of: overlay: set node fields from properties when add new overlay node frowand.list
2018-10-16 2:37 ` [PATCH v4 16/18] of: unittest: allow base devicetree to have symbol metadata frowand.list
2018-10-16 2:37 ` [PATCH v4 17/18] of: unittest: find overlays[] entry by name instead of index frowand.list
2018-10-16 2:37 ` [PATCH v4 18/18] of: unittest: initialize args before calling of_*parse_*() frowand.list
2018-10-16 9:47 ` [PATCH v4 00/18] of: overlay: validation checks, subsequent fixes Michael Ellerman
2018-10-17 3:08 ` Frank Rowand
2018-10-17 21:16 ` Alan Tull
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181018170303.GA15557@bogus \
--to=robh@kernel.org \
--cc=atull@kernel.org \
--cc=benh@kernel.crashing.org \
--cc=devicetree@vger.kernel.org \
--cc=frowand.list@gmail.com \
--cc=linux-fpga@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mdf@kernel.org \
--cc=mpe@ellerman.id.au \
--cc=pantelis.antoniou@konsulko.com \
--cc=paulus@samba.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).