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@xxxxxxx>
---
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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