tree 9c6b4b3204f06317c830457e091ff2c83272ea09
parent bfa0e9a07cd31f3858239dbc93011b82780acf4b
author Ed Swierk <eswierk@arastra.com> 1159226736 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1159231116 -0700

[PATCH] load_module: no BUG if module_subsys uninitialized

Invoking load_module() before param_sysfs_init() is called crashes in
mod_sysfs_setup(), since the kset in module_subsys is not initialized yet.

In my case, net-pf-1 is getting modprobed as a result of hotplug trying to
create a UNIX socket.  Calls to hotplug begin after the topology_init
initcall.

Another patch for the same symptom (module_subsys-initialize-earlier.patch)
moves param_sysfs_init() to the subsys initcalls, but this is still not
early enough in the boot process in some cases.  In particular,
topology_init() causes /sbin/hotplug to run, which requests net-pf-1 (the
UNIX socket protocol) which can be compiled as a module.  Moving
param_sysfs_init() to the postcore initcalls fixes this particular race,
but there might well be other cases where a usermodehelper causes a module
to load earlier still.

The patch makes load_module() return an error rather than crashing the
kernel if invoked before module_subsys is initialized.

Cc: Mark Huang <mlhuang@cs.princeton.edu>
Cc: Greg KH <greg@kroah.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>