From 420f0de965a80b7060d23d2c23cddaed4e4ad2eb Mon Sep 17 00:00:00 2001
From: Rob Herring <robh@kernel.org>
Date: Fri, 18 Aug 2023 15:40:59 -0500
Subject: [PATCH] of: dynamic: Fix race in getting old property when updating
property
__of_update_property() returns the existing property if there is one, but
that value is never added to the changeset. Updates work because the
existing property was also retrieved before in of_changeset_action(),
but that is racy as of_changeset_action() doesn't hold any locks. The
property could be changed before the changeset is applied.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230801-dt-changeset-fixes-v3-4-5f0410e007dd@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
---
drivers/of/dynamic.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index b2b921bcbbcbc..38dc536bc64c3 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -564,7 +564,7 @@ static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
{
- struct property *old_prop, **propp;
+ struct property **propp;
unsigned long flags;
int ret = 0;
@@ -604,7 +604,7 @@ static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
}
}
- ret = __of_update_property(ce->np, ce->prop, &old_prop);
+ ret = __of_update_property(ce->np, ce->prop, &ce->old_prop);
break;
default:
ret = -EINVAL;
@@ -908,9 +908,6 @@ int of_changeset_action(struct of_changeset *ocs, unsigned long action,
ce->np = of_node_get(np);
ce->prop = prop;
- if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
- ce->old_prop = of_find_property(np, prop->name, NULL);
-
/* add it to the list */
list_add_tail(&ce->node, &ocs->entries);
return 0;
--
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