Messages in this thread Patch in this message | | | From | NeilBrown <> | Date | Wed, 16 Apr 2014 14:03:36 +1000 | Subject | [PATCH 14/19] driver core: set PF_FSTRANS while holding gdp_mutex |
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lockdep reports a locking chain:
sk_lock-AF_INET --> rtnl_mutex --> gdp_mutex
As sk_lock can be needed for memory reclaim (when loop-back NFS is in use at least), any memory allocation under gdp_mutex needs to be protected by PF_FSTRANS.
The path frome rtnl_mutex to gdp_mutex is
[<ffffffff81841ecc>] get_device_parent+0x4c/0x1f0 [<ffffffff81842496>] device_add+0xe6/0x610 [<ffffffff81ac5f2a>] netdev_register_kobject+0x7a/0x130 [<ffffffff81aaf5d4>] register_netdevice+0x354/0x550 [<ffffffff81aaf7e5>] register_netdev+0x15/0x30
Signed-off-by: NeilBrown <neilb@suse.de> --- drivers/base/core.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/base/core.c b/drivers/base/core.c index 2b567177ef78..1a2735237650 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -750,6 +750,7 @@ static struct kobject *get_device_parent(struct device *dev, struct kobject *kobj = NULL; struct kobject *parent_kobj; struct kobject *k; + unsigned int pflags; #ifdef CONFIG_BLOCK /* block disks show up in /sys/block */ @@ -788,7 +789,9 @@ static struct kobject *get_device_parent(struct device *dev, } /* or create a new class-directory at the parent device */ + current_set_flags_nested(&pflags, PF_FSTRANS); k = class_dir_create_and_add(dev->class, parent_kobj); + current_restore_flags_nested(&pflags, PF_FSTRANS); /* do not emit an uevent for this simple "glue" directory */ mutex_unlock(&gdp_mutex); return k;
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