From 348eefca497a81d2b4c7a70d22495d14d63c863f Mon Sep 17 00:00:00 2001 From: Xiubo Li Date: Thu, 17 Apr 2014 15:48:29 +0800 Subject: [PATCH] of: fix race between search and remove in of_update_property() The of_update_property() is intented to update a property in a node and if the property does not exist, will add it. The second search of the property is possibly won't be found, that maybe removed by other thread just before the second search begain. Using the __of_find_property() and __of_add_property() instead and move them into lock operations. Signed-off-by: Xiubo Li [grant.likely: conflict with another change in same function] Signed-off-by: Grant Likely --- drivers/of/base.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/of/base.c b/drivers/of/base.c index 6d4ee22708c93..63ae00ec72ff8 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -1800,7 +1800,7 @@ int of_update_property(struct device_node *np, struct property *newprop) { struct property **next, *oldprop; unsigned long flags; - int rc, found = 0; + int rc; rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop); if (rc) @@ -1809,30 +1809,34 @@ int of_update_property(struct device_node *np, struct property *newprop) if (!newprop->name) return -EINVAL; - oldprop = of_find_property(np, newprop->name, NULL); - if (!oldprop) - return of_add_property(np, newprop); - raw_spin_lock_irqsave(&devtree_lock, flags); next = &np->properties; - while (*next) { + oldprop = __of_find_property(np, newprop->name, NULL); + if (!oldprop) { + /* add the new node */ + rc = __of_add_property(np, newprop); + } else while (*next) { + /* replace the node */ if (*next == oldprop) { - /* found the node */ newprop->next = oldprop->next; *next = newprop; oldprop->next = np->deadprops; np->deadprops = oldprop; - found = 1; break; } next = &(*next)->next; } raw_spin_unlock_irqrestore(&devtree_lock, flags); - if (!found) - return -ENODEV; + if (rc) + return rc; + + /* At early boot, bail out and defer setup to of_init() */ + if (!of_kset) + return 0; /* Update the sysfs attribute */ - sysfs_remove_bin_file(&np->kobj, &oldprop->attr); + if (oldprop) + sysfs_remove_bin_file(&np->kobj, &oldprop->attr); __of_add_property_sysfs(np, newprop); return 0; -- 2.39.5