linux.git/drivers/base/firmware_class.c, branch v3.3-rc2

PM / Sleep: Fix read_unlock_usermodehelper() call.

2012-01-23T20:59:08+00:00

Commit b298d289
 "PM / Sleep: Fix freezer failures due to racy usermodehelper_is_disabled()"
added read_unlock_usermodehelper() but read_unlock_usermodehelper() is called
without read_lock_usermodehelper() when kmalloc() failed.

Signed-off-by: Tetsuo Handa 
Acked-by: Srivatsa S. Bhat 
Signed-off-by: Rafael J. Wysocki

Merge branch 'pm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2012-01-08T21:10:57+00:00

* 'pm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (76 commits)
  PM / Hibernate: Implement compat_ioctl for /dev/snapshot
  PM / Freezer: fix return value of freezable_schedule_timeout_killable()
  PM / shmobile: Allow the A4R domain to be turned off at run time
  PM / input / touchscreen: Make st1232 use device PM QoS constraints
  PM / QoS: Introduce dev_pm_qos_add_ancestor_request()
  PM / shmobile: Remove the stay_on flag from SH7372's PM domains
  PM / shmobile: Don't include SH7372's INTCS in syscore suspend/resume
  PM / shmobile: Add support for the sh7372 A4S power domain / sleep mode
  PM: Drop generic_subsys_pm_ops
  PM / Sleep: Remove forward-only callbacks from AMBA bus type
  PM / Sleep: Remove forward-only callbacks from platform bus type
  PM: Run the driver callback directly if the subsystem one is not there
  PM / Sleep: Make pm_op() and pm_noirq_op() return callback pointers
  PM/Devfreq: Add Exynos4-bus device DVFS driver for Exynos4210/4212/4412.
  PM / Sleep: Merge internal functions in generic_ops.c
  PM / Sleep: Simplify generic system suspend callbacks
  PM / Hibernate: Remove deprecated hibernation snapshot ioctls
  PM / Sleep: Fix freezer failures due to racy usermodehelper_is_disabled()
  ARM: S3C64XX: Implement basic power domain support
  PM / shmobile: Use common always on power domain governor
  ...

Fix up trivial conflict in fs/xfs/xfs_buf.c due to removal of unused
XBT_FORCE_SLEEP bit

firmware: Fix an oops on reading fw_priv->fw in sysfs loading file

2012-01-05T00:31:29+00:00

This oops was reported recently:
firmware_loading_store+0xf9/0x17b
dev_attr_store+0x20/0x22
sysfs_write_file+0x101/0x134
vfs_write+0xac/0xf3
sys_write+0x4a/0x6e
system_call_fastpath+0x16/0x1b

The complete backtrace was unfortunately not captured, but details can be found
here:
https://bugzilla.redhat.com/show_bug.cgi?id=769920

The cause is fairly clear.

Its caused by the fact that firmware_loading_store has a case 0 in its
switch statement that reads and writes the fw_priv->fw poniter without the
protection of the fw_lock mutex.  since there is a window between the time that
_request_firmware sets fw_priv->fw to NULL and the time the corresponding sysfs
file is unregistered, its possible for a user space application to race in, and
write a zero to the loading file, causing a NULL dereference in
firmware_loading_store.  Fix it by extending the protection of the fw_lock mutex
to cover all of the firware_loading_store function.

Signed-off-by: Neil Horman 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

PM / Sleep: Fix freezer failures due to racy usermodehelper_is_disabled()

2011-12-09T22:36:36+00:00

Commit a144c6a (PM: Print a warning if firmware is requested when tasks
are frozen) introduced usermodehelper_is_disabled() to warn and exit
immediately if firmware is requested when usermodehelpers are disabled.

However, it is racy. Consider the following scenario, currently used in
drivers/base/firmware_class.c:

...
if (usermodehelper_is_disabled())
        goto out;

/* Do actual work */
...

out:
        return err;

Nothing prevents someone from disabling usermodehelpers just after the check
in the 'if' condition, which means that it is quite possible to try doing the
"actual work" with usermodehelpers disabled, leading to undesirable
consequences.

In particular, this race condition in _request_firmware() causes task freezing
failures whenever suspend/hibernation is in progress because, it wrongly waits
to get the firmware/microcode image from userspace when actually the
usermodehelpers are disabled or userspace has been frozen.
Some of the example scenarios that cause freezing failures due to this race
are those that depend on userspace via request_firmware(), such as x86
microcode module initialization and microcode image reload.

Previous discussions about this issue can be found at:
http://thread.gmane.org/gmane.linux.kernel/1198291/focus=1200591

This patch adds proper synchronization to fix this issue.

It is to be noted that this patchset fixes the freezing failures but doesn't
remove the warnings. IOW, it does not attempt to add explicit synchronization
to x86 microcode driver to avoid requesting microcode image at inopportune
moments. Because, the warnings were introduced to highlight such cases, in the
first place. And we need not silence the warnings, since we take care of the
*real* problem (freezing failure) and hence, after that, the warnings are
pretty harmless anyway.

Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Rafael J. Wysocki

firmware loader: allow builtin firmware load even if usermodehelper is disabled

2011-08-24T22:55:30+00:00

In commit a144c6a6c924 ("PM: Print a warning if firmware is requested
when tasks are frozen") we not only printed a warning if somebody tried
to load the firmware when tasks are frozen - we also failed the load.

But that check was done before the check for built-in firmware, and then
when we disallowed usermode helpers during bootup (commit 288d5abec831:
"Boot up with usermodehelper disabled"), that actually means that
built-in modules can no longer load their firmware even if the firmware
is built in too.  Which used to work, and some people depended on it for
the R100 driver.

So move the test for usermodehelper_is_disabled() down, to after
checking the built-in firmware.

This should fix:

	https://bugzilla.kernel.org/show_bug.cgi?id=40952

Reported-by: James Cloos 
Bisected-by: Elimar Riesebieter 
Cc: Michel Dänzer 
Cc: Rafael Wysocki 
Cc: Greg Kroah-Hartman 
Cc: Valdis Kletnieks 
Signed-off-by: Linus Torvalds

PM: Print a warning if firmware is requested when tasks are frozen

2011-05-17T21:19:17+00:00

Some drivers erroneously use request_firmware() from their ->resume()
(or ->thaw(), or ->restore()) callbacks, which is not going to work
unless the firmware has been built in.  This causes system resume to
stall until the firmware-loading timeout expires, which makes users
think that the resume has failed and reboot their machines
unnecessarily.  For this reason, make _request_firmware() print a
warning and return immediately with error code if it has been called
when tasks are frozen and it's impossible to start any new usermode
helpers.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Greg Kroah-Hartman 
Reviewed-by: Valdis Kletnieks

firmware_classs: change val uevent's type to bool

2011-02-03T23:39:17+00:00

Some place in firmware_class.c using "int uevent" define, but others use "bool
uevent".
This patch replace all int uevent define to bool.

Signed-off-by: Bob Liu 
Acked-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

firmware_class: fix typo in error path

2010-08-24T01:12:46+00:00

In the error path, _request_firmware sets
firmware_p to NULL rather than *firmware_p,
which leads to passing a freed firmware
struct to drivers when the firmware file
cannot be found. Fix this.

Broken by commit f8a4bd3456b988fc73b2c.

Reported-by: Wey-Yi Guy 
Signed-off-by: Johannes Berg 
Acked-by: Dmitry Torokhov 
Signed-off-by: Pekka Enberg 
Signed-off-by: Greg Kroah-Hartman

firmware loader: embed device into firmware_priv structure

2010-08-05T20:53:34+00:00

Both these structures have the same lifetime rules so instead of allocating
and managing them separately embed struct device into struct firmware_priv.
Also make sure to delete sysfs attributes ourselves instead of expecting
sysfs to clean up our mess.

Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

firmware loader: use statically initialized data attribute

2010-08-05T20:53:34+00:00

There is no reason why we are using a template for binary attribute
and copying it into per-firmware data before registering. Using the
original works as well.

Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman