linux-stable.git/drivers/base, branch linux-4.12.y Linux kernel stable tree driver core: bus: Fix a potential double free 2017-09-09T15:39:29+00:00 Christophe JAILLET christophe.jaillet@wanadoo.fr 2017-08-29T19:23:49+00:00 af617519a8c23bf0065398b6d3ad503035cf4aac commit 0f9b011d3321ca1079c7a46c18cb1956fbdb7bcb upstream. The .release function of driver_ktype is 'driver_release()'. This function frees the container_of this kobject. So, this memory must not be freed explicitly in the error handling path of 'bus_add_driver()'. Otherwise a double free will occur. Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0f9b011d3321ca1079c7a46c18cb1956fbdb7bcb upstream.

The .release function of driver_ktype is 'driver_release()'.
This function frees the container_of this kobject.

So, this memory must not be freed explicitly in the error handling path of
'bus_add_driver()'. Otherwise a double free will occur.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: avoid invalid fallback aborts by using killable wait 2017-08-16T20:46:57+00:00 Luis R. Rodriguez mcgrof@kernel.org 2017-07-20T20:13:11+00:00 67e1a98e3a74a5e728f311f59282a242ab34406d commit 260d9f2fc5655a2552701cdd0b909c4466732f19 upstream. Commit 0cb64249ca500 ("firmware_loader: abort request if wait_for_completion is interrupted") added via 4.0 added support to abort the fallback mechanism when a signal was detected and wait_for_completion_interruptible() returned -ERESTARTSYS -- for instance when a user hits CTRL-C. The abort was overly *too* effective. When a child process terminates (successful or not) the signal SIGCHLD can be sent to the parent process which ran the child in the background and later triggered a sync request for firmware through a sysfs interface which relies on the fallback mechanism. This signal in turn can be recieved by the interruptible wait we constructed on firmware_class and detects it as an abort *before* userspace could get a chance to write the firmware. Upon failure -EAGAIN is returned, so userspace is also kept in the dark about exactly what happened. We can reproduce the issue with the fw_fallback.sh selftest: Before this patch: $ sudo tools/testing/selftests/firmware/fw_fallback.sh ... tools/testing/selftests/firmware/fw_fallback.sh: error - sync firmware request cancelled due to SIGCHLD After this patch: $ sudo tools/testing/selftests/firmware/fw_fallback.sh ... tools/testing/selftests/firmware/fw_fallback.sh: SIGCHLD on sync ignored as expected Fix this by making the wait killable -- only killable by SIGKILL (kill -9). We loose the ability to allow userspace to cancel a write with CTRL-C (SIGINT), however its been decided the compromise to require SIGKILL is worth the gains. Chances of this issue occuring are low due to the number of drivers upstream exclusively relying on the fallback mechanism for firmware (2 drivers), however this is observed in the field with custom drivers with sysfs triggers to load firmware. Only distributions relying on the fallback mechanism are impacted as well. An example reported issue was on Android, as follows: 1) Android init (pid=1) fork()s (say pid=42) [this child process is totally unrelated to firmware loading, it could be sleep 2; for all we care ] 2) Android init (pid=1) does a write() on a (driver custom) sysfs file which ends up calling request_firmware() kernel side 3) The firmware loading fallback mechanism is used, the request is sent to userspace and pid 1 waits in the kernel on wait_* 4) before firmware loading completes pid 42 dies (for any reason, even normal termination) 5) Kernel delivers SIGCHLD to pid=1 to tell it a child has died, which causes -ERESTARTSYS to be returned from wait_* 6) The kernel's wait aborts and return -EAGAIN for the request_firmware() caller. Fixes: 0cb64249ca500 ("firmware_loader: abort request if wait_for_completion is interrupted") Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com> Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Tested-by: Martin Fuzzey <mfuzzey@parkeon.com> Reported-by: Martin Fuzzey <mfuzzey@parkeon.com> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 260d9f2fc5655a2552701cdd0b909c4466732f19 upstream.

Commit 0cb64249ca500 ("firmware_loader: abort request if wait_for_completion
is interrupted") added via 4.0 added support to abort the fallback mechanism
when a signal was detected and wait_for_completion_interruptible() returned
-ERESTARTSYS -- for instance when a user hits CTRL-C. The abort was overly
*too* effective.

When a child process terminates (successful or not) the signal SIGCHLD can
be sent to the parent process which ran the child in the background and
later triggered a sync request for firmware through a sysfs interface which
relies on the fallback mechanism. This signal in turn can be recieved by the
interruptible wait we constructed on firmware_class and detects it as an
abort *before* userspace could get a chance to write the firmware. Upon
failure -EAGAIN is returned, so userspace is also kept in the dark about
exactly what happened.

We can reproduce the issue with the fw_fallback.sh selftest:

Before this patch:
$ sudo tools/testing/selftests/firmware/fw_fallback.sh
...
tools/testing/selftests/firmware/fw_fallback.sh: error - sync firmware request cancelled due to SIGCHLD

After this patch:
$ sudo tools/testing/selftests/firmware/fw_fallback.sh
...
tools/testing/selftests/firmware/fw_fallback.sh: SIGCHLD on sync ignored as expected

Fix this by making the wait killable -- only killable by SIGKILL (kill -9).
We loose the ability to allow userspace to cancel a write with CTRL-C
(SIGINT), however its been decided the compromise to require SIGKILL is
worth the gains.

Chances of this issue occuring are low due to the number of drivers upstream
exclusively relying on the fallback mechanism for firmware (2 drivers),
however this is observed in the field with custom drivers with sysfs
triggers to load firmware. Only distributions relying on the fallback
mechanism are impacted as well. An example reported issue was on Android,
as follows:

1) Android init (pid=1) fork()s (say pid=42) [this child process is totally
   unrelated to firmware loading, it could be sleep 2; for all we care ]
2) Android init (pid=1) does a write() on a (driver custom) sysfs file which
   ends up calling request_firmware() kernel side
3) The firmware loading fallback mechanism is used, the request is sent to
   userspace and pid 1 waits in the kernel on wait_*
4) before firmware loading completes pid 42 dies (for any reason, even
   normal termination)
5) Kernel delivers SIGCHLD to pid=1 to tell it a child has died, which
   causes -ERESTARTSYS to be returned from wait_*
6) The kernel's wait aborts and return -EAGAIN for the
   request_firmware() caller.

Fixes: 0cb64249ca500 ("firmware_loader: abort request if wait_for_completion is interrupted")
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Martin Fuzzey <mfuzzey@parkeon.com>
Reported-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: fix batched requests - send wake up on failure on direct lookups 2017-08-16T20:46:57+00:00 Luis R. Rodriguez mcgrof@kernel.org 2017-07-20T20:13:10+00:00 b1b5c0b23a909c0e6f7f8bddc111a68caf128242 commit 90d41e74a9c36a84e2efbd2a5b8d79299feee6fa upstream. Fix batched requests from waiting forever on failure. The firmware API batched requests feature has been broken since the API call request_firmware_direct() was introduced on commit bba3a87e982ad ("firmware: Introduce request_firmware_direct()"), added on v3.14 *iff* the firmware being requested was not present in *certain kernel builds* [0]. When no firmware is found the worker which goes on to finish never informs waiters queued up of this, so any batched request will stall in what seems to be forever (MAX_SCHEDULE_TIMEOUT). Sadly, a reboot will also stall, as the reboot notifier was only designed to kill custom fallback workers. The issue seems to the user as a type of soft lockup, what *actually* happens underneath the hood is a wait call which never completes as we failed to issue a completion on error. For device drivers with optional firmware schemes (ie, Intel iwlwifi, or Netronome -- even though it uses request_firmware() and not request_firmware_direct()), this could mean that when you boot a system with multiple cards the firmware will seem to never load on the system, or that the card is just not responsive even the driver initialization. Due to differences in scheduling possible this should not always trigger -- one would need to to ensure that multiple requests are in place at the right time for this to work, also release_firmware() must not be called prior to any other incoming request. The complexity may not be worth supporting batched requests in the future given the wait mechanism is only used also for the fallback mechanism. We'll keep it for now and just fix it. Its reported that at least with the Intel WiFi cards on one system this issue was creeping up 50% of the boots [0]. Before this commit batched requests testing revealed: ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n CONFIG_FW_LOADER_USER_HELPER=y Most common Linux distribution setup. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() FAIL OK request_firmware_direct() FAIL OK request_firmware_nowait(uevent=true) FAIL OK request_firmware_nowait(uevent=false) FAIL OK ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n CONFIG_FW_LOADER_USER_HELPER=n Only possible if CONFIG_DELL_RBU=n and CONFIG_LEDS_LP55XX_COMMON=n, rare. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() FAIL OK request_firmware_direct() FAIL OK request_firmware_nowait(uevent=true) FAIL OK request_firmware_nowait(uevent=false) FAIL OK ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y CONFIG_FW_LOADER_USER_HELPER=y Google Android setup. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() OK OK request_firmware_direct() FAIL OK request_firmware_nowait(uevent=true) OK OK request_firmware_nowait(uevent=false) OK OK ============================================================================ Ater this commit batched testing results: ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n CONFIG_FW_LOADER_USER_HELPER=y Most common Linux distribution setup. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() OK OK request_firmware_direct() OK OK request_firmware_nowait(uevent=true) OK OK request_firmware_nowait(uevent=false) OK OK ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n CONFIG_FW_LOADER_USER_HELPER=n Only possible if CONFIG_DELL_RBU=n and CONFIG_LEDS_LP55XX_COMMON=n, rare. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() OK OK request_firmware_direct() OK OK request_firmware_nowait(uevent=true) OK OK request_firmware_nowait(uevent=false) OK OK ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y CONFIG_FW_LOADER_USER_HELPER=y Google Android setup. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() OK OK request_firmware_direct() OK OK request_firmware_nowait(uevent=true) OK OK request_firmware_nowait(uevent=false) OK OK ============================================================================ [0] https://bugzilla.kernel.org/show_bug.cgi?id=195477 Fixes: bba3a87e982ad ("firmware: Introduce request_firmware_direct()" Reported-by: Nicolas <nbroeking@me.com> Reported-by: John Ewalt <jewalt@lgsinnovations.com> Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 90d41e74a9c36a84e2efbd2a5b8d79299feee6fa upstream.

Fix batched requests from waiting forever on failure.

The firmware API batched requests feature has been broken since the API call
request_firmware_direct() was introduced on commit bba3a87e982ad ("firmware:
Introduce request_firmware_direct()"), added on v3.14 *iff* the firmware
being requested was not present in *certain kernel builds* [0].

When no firmware is found the worker which goes on to finish never informs
waiters queued up of this, so any batched request will stall in what seems
to be forever (MAX_SCHEDULE_TIMEOUT). Sadly, a reboot will also stall, as
the reboot notifier was only designed to kill custom fallback workers. The
issue seems to the user as a type of soft lockup, what *actually* happens
underneath the hood is a wait call which never completes as we failed to
issue a completion on error.

For device drivers with optional firmware schemes (ie, Intel iwlwifi, or
Netronome -- even though it uses request_firmware() and not
request_firmware_direct()), this could mean that when you boot a system with
multiple cards the firmware will seem to never load on the system, or that
the card is just not responsive even the driver initialization. Due to
differences in scheduling possible this should not always trigger --
one would need to to ensure that multiple requests are in place at the
right time for this to work, also release_firmware() must not be called
prior to any other incoming request. The complexity may not be worth
supporting batched requests in the future given the wait mechanism is
only used also for the fallback mechanism. We'll keep it for now and
just fix it.

Its reported that at least with the Intel WiFi cards on one system this
issue was creeping up 50% of the boots [0].

Before this commit batched requests testing revealed:
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
CONFIG_FW_LOADER_USER_HELPER=y

Most common Linux distribution setup.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     FAIL                OK
request_firmware_direct()              FAIL                OK
request_firmware_nowait(uevent=true)   FAIL                OK
request_firmware_nowait(uevent=false)  FAIL                OK
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
CONFIG_FW_LOADER_USER_HELPER=n

Only possible if CONFIG_DELL_RBU=n and CONFIG_LEDS_LP55XX_COMMON=n, rare.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     FAIL                OK
request_firmware_direct()              FAIL                OK
request_firmware_nowait(uevent=true)   FAIL                OK
request_firmware_nowait(uevent=false)  FAIL                OK
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
CONFIG_FW_LOADER_USER_HELPER=y

Google Android setup.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     OK                  OK
request_firmware_direct()              FAIL                OK
request_firmware_nowait(uevent=true)   OK                  OK
request_firmware_nowait(uevent=false)  OK                  OK
============================================================================

Ater this commit batched testing results:
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
CONFIG_FW_LOADER_USER_HELPER=y

Most common Linux distribution setup.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     OK                  OK
request_firmware_direct()              OK                  OK
request_firmware_nowait(uevent=true)   OK                  OK
request_firmware_nowait(uevent=false)  OK                  OK
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
CONFIG_FW_LOADER_USER_HELPER=n

Only possible if CONFIG_DELL_RBU=n and CONFIG_LEDS_LP55XX_COMMON=n, rare.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     OK                  OK
request_firmware_direct()              OK                  OK
request_firmware_nowait(uevent=true)   OK                  OK
request_firmware_nowait(uevent=false)  OK                  OK
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
CONFIG_FW_LOADER_USER_HELPER=y

Google Android setup.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     OK                  OK
request_firmware_direct()              OK                  OK
request_firmware_nowait(uevent=true)   OK                  OK
request_firmware_nowait(uevent=false)  OK                  OK
============================================================================

[0] https://bugzilla.kernel.org/show_bug.cgi?id=195477

Fixes: bba3a87e982ad ("firmware: Introduce request_firmware_direct()"
Reported-by: Nicolas <nbroeking@me.com>
Reported-by: John Ewalt  <jewalt@lgsinnovations.com>
Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: fix batched requests - wake all waiters 2017-08-16T20:46:57+00:00 Luis R. Rodriguez mcgrof@kernel.org 2017-07-20T20:13:09+00:00 c2c32ed5e6bf3aa81d4c5e04be9f9ec2598ef2db commit e44565f62a72064e686f7a852137595ec94d78f2 upstream. The firmware cache mechanism serves two purposes, the secondary purpose is not well documented nor understood. This fixes a regression with the secondary purpose of the firmware cache mechanism: batched requests on successful lookups. Without this fix *any* time a batched request is triggered, secondary requests for which the batched request mechanism was designed for will seem to last forver and seem to never return. This issue is present for all kernel builds possible, and a hard reset is required. The firmware cache is used for: 1) Addressing races with file lookups during the suspend/resume cycle by keeping firmware in memory during the suspend/resume cycle 2) Batched requests for the same file rely only on work from the first file lookup, which keeps the firmware in memory until the last release_firmware() is called Batched requests *only* take effect if secondary requests come in prior to the first user calling release_firmware(). The devres name used for the internal firmware cache is used as a hint other pending requests are ongoing, the firmware buffer data is kept in memory until the last user of the buffer calls release_firmware(), therefore serializing requests and delaying the release until all requests are done. Batched requests wait for a wakup or signal so we can rely on the first file fetch to write to the pending secondary requests. Commit 5b029624948d ("firmware: do not use fw_lock for fw_state protection") ported the firmware API to use swait, and in doing so failed to convert complete_all() to swake_up_all() -- it used swake_up(), loosing the ability for *some* batched requests to take effect. We *could* fix this by just using swake_up_all() *but* swait is now known to be very special use case, so its best to just move away from it. So we just go back to using completions as before commit 5b029624948d ("firmware: do not use fw_lock for fw_state protection") given this was using complete_all(). Without this fix it has been reported plugging in two Intel 6260 Wifi cards on a system will end up enumerating the two devices only 50% of the time [0]. The ported swake_up() should have actually handled the case with two devices, however, *if more than two cards are used* the swake_up() would not have sufficed. This change is only part of the required fixes for batched requests. Another fix is provided in the next patch. This particular change should fix the cases where more than three requests with the same firmware name is used, otherwise batched requests will wait for MAX_SCHEDULE_TIMEOUT and just timeout eventually. Below is a summary of tests triggering batched requests on different kernel builds. Before this patch: ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n CONFIG_FW_LOADER_USER_HELPER=y Most common Linux distribution setup. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() FAIL FAIL request_firmware_direct() FAIL FAIL request_firmware_nowait(uevent=true) FAIL FAIL request_firmware_nowait(uevent=false) FAIL FAIL ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n CONFIG_FW_LOADER_USER_HELPER=n Only possible if CONFIG_DELL_RBU=n and CONFIG_LEDS_LP55XX_COMMON=n, rare. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() FAIL FAIL request_firmware_direct() FAIL FAIL request_firmware_nowait(uevent=true) FAIL FAIL request_firmware_nowait(uevent=false) FAIL FAIL ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y CONFIG_FW_LOADER_USER_HELPER=y Google Android setup. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() FAIL FAIL request_firmware_direct() FAIL FAIL request_firmware_nowait(uevent=true) FAIL FAIL request_firmware_nowait(uevent=false) FAIL FAIL ============================================================================ After this patch: ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n CONFIG_FW_LOADER_USER_HELPER=y Most common Linux distribution setup. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() FAIL OK request_firmware_direct() FAIL OK request_firmware_nowait(uevent=true) FAIL OK request_firmware_nowait(uevent=false) FAIL OK ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n CONFIG_FW_LOADER_USER_HELPER=n Only possible if CONFIG_DELL_RBU=n and CONFIG_LEDS_LP55XX_COMMON=n, rare. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() FAIL OK request_firmware_direct() FAIL OK request_firmware_nowait(uevent=true) FAIL OK request_firmware_nowait(uevent=false) FAIL OK ============================================================================ CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y CONFIG_FW_LOADER_USER_HELPER=y Google Android setup. API-type no-firmware-found firmware-found ---------------------------------------------------------------------- request_firmware() OK OK request_firmware_direct() FAIL OK request_firmware_nowait(uevent=true) OK OK request_firmware_nowait(uevent=false) OK OK ============================================================================ [0] https://bugzilla.kernel.org/show_bug.cgi?id=195477 Cc: Ming Lei <ming.lei@redhat.com> Fixes: 5b029624948d ("firmware: do not use fw_lock for fw_state protection") Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e44565f62a72064e686f7a852137595ec94d78f2 upstream.

The firmware cache mechanism serves two purposes, the secondary purpose is
not well documented nor understood. This fixes a regression with the
secondary purpose of the firmware cache mechanism: batched requests on
successful lookups. Without this fix *any* time a batched request is
triggered, secondary requests for which the batched request mechanism
was designed for will seem to last forver and seem to never return.
This issue is present for all kernel builds possible, and a hard reset
is required.

The firmware cache is used for:

1) Addressing races with file lookups during the suspend/resume cycle
   by keeping firmware in memory during the suspend/resume cycle

2) Batched requests for the same file rely only on work from the first file
   lookup, which keeps the firmware in memory until the last
   release_firmware() is called

Batched requests *only* take effect if secondary requests come in prior to
the first user calling release_firmware(). The devres name used for the
internal firmware cache is used as a hint other pending requests are
ongoing, the firmware buffer data is kept in memory until the last user of
the buffer calls release_firmware(), therefore serializing requests and
delaying the release until all requests are done.

Batched requests wait for a wakup or signal so we can rely on the first file
fetch to write to the pending secondary requests. Commit 5b029624948d
("firmware: do not use fw_lock for fw_state protection") ported the firmware
API to use swait, and in doing so failed to convert complete_all() to
swake_up_all() -- it used swake_up(), loosing the ability for *some* batched
requests to take effect.

We *could* fix this by just using swake_up_all() *but* swait is now known
to be very special use case, so its best to just move away from it. So we
just go back to using completions as before commit 5b029624948d ("firmware:
do not use fw_lock for fw_state protection") given this was using
complete_all().

Without this fix it has been reported plugging in two Intel 6260 Wifi cards
on a system will end up enumerating the two devices only 50% of the time
[0]. The ported swake_up() should have actually handled the case with two
devices, however, *if more than two cards are used* the swake_up() would
not have sufficed. This change is only part of the required fixes for
batched requests. Another fix is provided in the next patch.

This particular change should fix the cases where more than three requests
with the same firmware name is used, otherwise batched requests will wait
for MAX_SCHEDULE_TIMEOUT and just timeout eventually.

Below is a summary of tests triggering batched requests on different
kernel builds.

Before this patch:
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
CONFIG_FW_LOADER_USER_HELPER=y

Most common Linux distribution setup.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     FAIL                FAIL
request_firmware_direct()              FAIL                FAIL
request_firmware_nowait(uevent=true)   FAIL                FAIL
request_firmware_nowait(uevent=false)  FAIL                FAIL
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
CONFIG_FW_LOADER_USER_HELPER=n

Only possible if CONFIG_DELL_RBU=n and CONFIG_LEDS_LP55XX_COMMON=n, rare.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     FAIL                FAIL
request_firmware_direct()              FAIL                FAIL
request_firmware_nowait(uevent=true)   FAIL                FAIL
request_firmware_nowait(uevent=false)  FAIL                FAIL
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
CONFIG_FW_LOADER_USER_HELPER=y

Google Android setup.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     FAIL                FAIL
request_firmware_direct()              FAIL                FAIL
request_firmware_nowait(uevent=true)   FAIL                FAIL
request_firmware_nowait(uevent=false)  FAIL                FAIL
============================================================================

After this patch:
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
CONFIG_FW_LOADER_USER_HELPER=y

Most common Linux distribution setup.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     FAIL                OK
request_firmware_direct()              FAIL                OK
request_firmware_nowait(uevent=true)   FAIL                OK
request_firmware_nowait(uevent=false)  FAIL                OK
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
CONFIG_FW_LOADER_USER_HELPER=n

Only possible if CONFIG_DELL_RBU=n and CONFIG_LEDS_LP55XX_COMMON=n, rare.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     FAIL                OK
request_firmware_direct()              FAIL                OK
request_firmware_nowait(uevent=true)   FAIL                OK
request_firmware_nowait(uevent=false)  FAIL                OK
============================================================================
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
CONFIG_FW_LOADER_USER_HELPER=y

Google Android setup.

API-type                               no-firmware-found   firmware-found
----------------------------------------------------------------------
request_firmware()                     OK                  OK
request_firmware_direct()              FAIL                OK
request_firmware_nowait(uevent=true)   OK                  OK
request_firmware_nowait(uevent=false)  OK                  OK
============================================================================

[0] https://bugzilla.kernel.org/show_bug.cgi?id=195477

Cc: Ming Lei <ming.lei@redhat.com>
Fixes: 5b029624948d ("firmware: do not use fw_lock for fw_state protection")
Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PM / Domains: defer dev_pm_domain_set() until genpd->attach_dev succeeds if present 2017-07-27T22:10:24+00:00 Sudeep Holla Sudeep.Holla@arm.com 2017-07-14T10:51:48+00:00 f564ff0c792c69569c5fceb896c6eefe2040e625 commit 975e83cfb8dc16e7a2fdc58188c77c0c605876c2 upstream. If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets the PM domain for the device unconditionally. When subsequent attempts are made to call genpd_dev_pm_attach, it may return -EEXISTS checking dev->pm_domain without re-attempting to call attach_dev or power_on. platform_drv_probe then attempts to call drv->probe as the return value -EEXIST != -EPROBE_DEFER, which may end up in a situation where the device is accessed without it's power domain switched on. Fixes: f104e1e5ef57 (PM / Domains: Re-order initialization of generic_pm_domain_data) Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 975e83cfb8dc16e7a2fdc58188c77c0c605876c2 upstream.

If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach
may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets
the PM domain for the device unconditionally.

When subsequent attempts are made to call genpd_dev_pm_attach, it may
return -EEXISTS checking dev->pm_domain without re-attempting to call
attach_dev or power_on.

platform_drv_probe then attempts to call drv->probe as the return value
-EEXIST != -EPROBE_DEFER, which may end up in a situation where the
device is accessed without it's power domain switched on.

Fixes: f104e1e5ef57 (PM / Domains: Re-order initialization of generic_pm_domain_data)
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PM / Domains: Fix unsafe iteration over modified list of domains 2017-07-27T22:10:07+00:00 Krzysztof Kozlowski krzk@kernel.org 2017-06-28T14:56:20+00:00 adc0157721d07473e1455c669d20fd615373631f commit a7e2d1bce4c1db471f1cbc0c4666a3112bbf0994 upstream. of_genpd_remove_last() iterates over list of domains and removes matching element thus it has to use safe version of list iteration. Fixes: 17926551c98a (PM / Domains: Add support for removing nested PM domains by provider) Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a7e2d1bce4c1db471f1cbc0c4666a3112bbf0994 upstream.

of_genpd_remove_last() iterates over list of domains and removes
matching element thus it has to use safe version of list iteration.

Fixes: 17926551c98a (PM / Domains: Add support for removing nested PM domains by provider)
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PM / Domains: Fix unsafe iteration over modified list of domain providers 2017-07-27T22:10:07+00:00 Krzysztof Kozlowski krzk@kernel.org 2017-06-28T14:56:19+00:00 01ee0ee75933c106bc8772491fb9d287439e9b5f commit b556b15dc04e9b9b98790f04c21acf5e24f994b2 upstream. of_genpd_del_provider() iterates over list of domain provides and removes matching element thus it has to use safe version of list iteration. Fixes: aa42240ab254 (PM / Domains: Add generic OF-based PM domain look-up) Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b556b15dc04e9b9b98790f04c21acf5e24f994b2 upstream.

of_genpd_del_provider() iterates over list of domain provides and
removes matching element thus it has to use safe version of list
iteration.

Fixes: aa42240ab254 (PM / Domains: Add generic OF-based PM domain look-up)
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PM / Domains: Fix unsafe iteration over modified list of device links 2017-07-27T22:10:07+00:00 Krzysztof Kozlowski krzk@kernel.org 2017-06-28T14:56:18+00:00 61461312f0b0eb4e71915efd4c852baa7aa2b4b1 commit c6e83cac3eda5f7dd32ee1453df2f7abb5c6cd46 upstream. pm_genpd_remove_subdomain() iterates over domain's master_links list and removes matching element thus it has to use safe version of list iteration. Fixes: f721889ff65a ("PM / Domains: Support for generic I/O PM domains (v8)") Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c6e83cac3eda5f7dd32ee1453df2f7abb5c6cd46 upstream.

pm_genpd_remove_subdomain() iterates over domain's master_links list and
removes matching element thus it has to use safe version of list
iteration.

Fixes: f721889ff65a ("PM / Domains: Support for generic I/O PM domains (v8)")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PM / QoS: return -EINVAL for bogus strings 2017-07-21T04:59:13+00:00 Dan Carpenter dan.carpenter@oracle.com 2017-07-10T07:21:40+00:00 b62226beb332defcf963de1b418d4b7612419d38 commit 2ca30331c156ca9e97643ad05dd8930b8fe78b01 upstream. In the current code, if the user accidentally writes a bogus command to this sysfs file, then we set the latency tolerance to an uninitialized variable. Fixes: 2d984ad132a8 (PM / QoS: Introcuce latency tolerance device PM QoS type) Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2ca30331c156ca9e97643ad05dd8930b8fe78b01 upstream.

In the current code, if the user accidentally writes a bogus command to
this sysfs file, then we set the latency tolerance to an uninitialized
variable.

Fixes: 2d984ad132a8 (PM / QoS: Introcuce latency tolerance device PM QoS type)
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PM / wakeirq: Convert to SRCU 2017-07-21T04:59:12+00:00 Thomas Gleixner tglx@linutronix.de 2017-06-25T17:31:13+00:00 a8f82d6ea54cd2a21c2bcd8fb5cc076393140a2c commit ea0212f40c6bc0594c8eff79266759e3ecd4bacc upstream. The wakeirq infrastructure uses RCU to protect the list of wakeirqs. That breaks the irq bus locking infrastructure, which is allows sleeping functions to be called so interrupt controllers behind slow busses, e.g. i2c, can be handled. The wakeirq functions hold rcu_read_lock and call into irq functions, which in case of interrupts using the irq bus locking will trigger a might_sleep() splat. Convert the wakeirq infrastructure to Sleepable RCU and unbreak it. Fixes: 4990d4fe327b (PM / Wakeirq: Add automated device wake IRQ handling) Reported-by: Brian Norris <briannorris@chromium.org> Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ea0212f40c6bc0594c8eff79266759e3ecd4bacc upstream.

The wakeirq infrastructure uses RCU to protect the list of wakeirqs. That
breaks the irq bus locking infrastructure, which is allows sleeping
functions to be called so interrupt controllers behind slow busses,
e.g. i2c, can be handled.

The wakeirq functions hold rcu_read_lock and call into irq functions, which
in case of interrupts using the irq bus locking will trigger a
might_sleep() splat.

Convert the wakeirq infrastructure to Sleepable RCU and unbreak it.

Fixes: 4990d4fe327b (PM / Wakeirq: Add automated device wake IRQ handling)
Reported-by: Brian Norris <briannorris@chromium.org>
Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>