linux-toradex.git/lib/kobject_uevent.c, branch v2.6.32.9

driver core: allow non-root users to listen to uevents

2009-04-16T23:17:09+00:00

Users can read sysfs files, there is no reason they should not be
allowed to listen to uevents.  This lets xorg and other userspace
programs properly get these messages without having to be root.

Signed-off-by: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Revert "kobject: don't block for each kobject_uevent".

2009-04-16T21:41:24+00:00

This reverts commit f520360d93cdc37de5d972dac4bf3bdef6a7f6a7.

Tetsuo Handa, running a kernel with CONFIG_DEBUG_PAGEALLOC=y and
CONFIG_UEVENT_HELPER_PATH=/sbin/hotplug, has been hitting RCU detected
CPU stalls: it's been spinning in the loop where do_execve() counts up
the args (but why wasn't fixup_exception working? dunno).

The recent change, switching kobject_uevent_env() from UMH_WAIT_EXEC
to UMH_NO_WAIT, is broken: the exec uses args on the local stack here,
and an env which is kfreed as soon as call_usermodehelper() returns.
It very much needs to wait for the exec to be done.

An alternative would be to keep the UMH_NO_WAIT, and complicate the code
to allocate and free these resources correctly? but no, as GregKH
pointed out when making the commit, CONFIG_UEVENT_HELPER_PATH="" is a
much better optimization - though some distros are still saying
/sbin/hotplug in their .config, yet with no such binary in their initrd
or their root.

Reported-by: Tetsuo Handa 
Signed-off-by: Hugh Dickins 
Acked-by: Greg Kroah-Hartman 
Acked-by: Arjan van de Ven 
Acked-by: Will Newton 
Signed-off-by: Linus Torvalds

Merge branch 'master' of /home/davem/src/GIT/linux-2.6/

2009-03-26T22:23:24+00:00

Conflicts:
	drivers/net/wimax/i2400m/usb-notif.c

kobject: don't block for each kobject_uevent

2009-03-24T23:38:26+00:00

Right now, the kobject_uevent code blocks for each uevent that's being
generated, due to using (for hystoric reasons) UHM_WAIT_EXEC as flag to
call_usermode_helper().  Specifically, the effect is that each uevent
that is being sent causes the code to wake up keventd, then block until
keventd has processed the work. Needless to say, this happens many times
during the system boot.

This patches changes that to UHN_NO_WAIT (brilliant name for a constant
btw) so that we only schedule the work to fire the uevent message, but
do not wait for keventd to process the work.

This removes one of the bottlenecks during boot; each one of them is
only a small effect, but the sum of them does add up.

[Note, distros that need this are broken, they should be setting
CONFIG_UEVENT_HELPER_PATH to "", that way this code path will never be
excuted at all -- gregkh]

Signed-off-by: Arjan van de Ven 
Signed-off-by: Greg Kroah-Hartman

Driver core: implement uevent suppress in kobject

2009-03-24T23:38:26+00:00

This patch implements uevent suppress in kobject and removes it
from struct device, based on the following ideas:

1,Uevent sending should be one attribute of kobject, so suppressing it
in kobject layer is more natural than in device layer. By this way,
we can do it for other objects embedded with kobject.

2,It may save several bytes for each instance of struct device.(On my
omap3(32bit ARM) based box, can save 8bytes per device object)

This patch also introduces dev_set|get_uevent_suppress() helpers to
set and query uevent_suppress attribute in case to help kobject
as private part of struct device in future.

[This version is against the latest driver-core patch set of Greg,please
ignore the last version.]

Signed-off-by: Ming Lei 
Signed-off-by: Greg Kroah-Hartman

netlink: change return-value logic of netlink_broadcast()

2009-02-06T07:56:36+00:00

Currently, netlink_broadcast() reports errors to the caller if no
messages at all were delivered:

1) If, at least, one message has been delivered correctly, returns 0.
2) Otherwise, if no messages at all were delivered due to skb_clone()
   failure, return -ENOBUFS.
3) Otherwise, if there are no listeners, return -ESRCH.

With this patch, the caller knows if the delivery of any of the
messages to the listeners have failed:

1) If it fails to deliver any message (for whatever reason), return
   -ENOBUFS.
2) Otherwise, if all messages were delivered OK, returns 0.
3) Otherwise, if no listeners, return -ESRCH.

In the current ctnetlink code and in Netfilter in general, we can add
reliable logging and connection tracking event delivery by dropping the
packets whose events were not successfully delivered over Netlink. Of
course, this option would be settable via /proc as this approach reduces
performance (in terms of filtered connections per seconds by a stateful
firewall) but providing reliable logging and event delivery (for
conntrackd) in return.

This patch also changes some clients of netlink_broadcast() that
may report ENOBUFS errors via printk. This error handling is not
of any help. Instead, the userspace daemons that are listening to
those netlink messages should resync themselves with the kernel-side
if they hit ENOBUFS.

BTW, netlink_broadcast() clients include those that call
cn_netlink_send(), nlmsg_multicast() and genlmsg_multicast() since they
internally call netlink_broadcast() and return its error value.

Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: David S. Miller

kobject: return the result of uevent sending by netlink

2009-01-06T18:44:31+00:00

We need to return the result of uevent sending by netlink
to caller, when uevent_helper is disabled and CONFIG_NET
is defined.

Signed-off-by: Ming Lei 
Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

uevent: don't pass envp_ext[] as format string in kobject_uevent_env()

2009-01-06T18:44:31+00:00

kobject_uevent_env() uses envp_ext[] as verbatim format string which
can cause problems ranging from unexpectedly mangled string to oops if
a string in envp_ext[] contains substring which can be interpreted as
format.  Fix it.

Signed-off-by: Tejun Heo 
Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Use WARN() in lib/

2008-07-26T19:00:07+00:00

Use WARN() instead of a printk+WARN_ON() pair; this way the message becomes
part of the warning section for better reporting/collection.  In addition, one
of the if() clauses collapes into the WARN() entirely now.

Signed-off-by: Arjan van de Ven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kobject: Transmit return value of call_usermodehelper() to caller

2008-07-22T04:55:00+00:00

kobject_uevent_env() drops the return value of call_usermodehelper().
It will make upper caller, such as dm_send_uevents(), to lose error
information.

BTW, Previously kobject_uevent_env() transmitted return of
call_usermodehelper() to callers, but
commit	5f123fbd80f4f788554636f02bf73e40f914e0d6
"[PATCH] merge kobject_uevent and kobject_hotplug" removed it.

Signed-off-by: Wang Chen 
Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman