linux-stable.git/kernel/power, branch linux-5.18.y

PM: hibernate: defer device probing when resuming from hibernation

2022-08-17T12:40:26+00:00

[ Upstream commit 8386c414e27caba8501119948e9551e52b527f59 ]

syzbot is reporting hung task at misc_open() [1], for there is a race
window of AB-BA deadlock which involves probe_count variable. Currently
wait_for_device_probe() from snapshot_open() from misc_open() can sleep
forever with misc_mtx held if probe_count cannot become 0.

When a device is probed by hub_event() work function, probe_count is
incremented before the probe function starts, and probe_count is
decremented after the probe function completed.

There are three cases that can prevent probe_count from dropping to 0.

  (a) A device being probed stopped responding (i.e. broken/malicious
      hardware).

  (b) A process emulating a USB device using /dev/raw-gadget interface
      stopped responding for some reason.

  (c) New device probe requests keeps coming in before existing device
      probe requests complete.

The phenomenon syzbot is reporting is (b). A process which is holding
system_transition_mutex and misc_mtx is waiting for probe_count to become
0 inside wait_for_device_probe(), but the probe function which is called
 from hub_event() work function is waiting for the processes which are
blocked at mutex_lock(&misc_mtx) to respond via /dev/raw-gadget interface.

This patch mitigates (b) by deferring wait_for_device_probe() from
snapshot_open() to snapshot_write() and snapshot_ioctl(). Please note that
the possibility of (b) remains as long as any thread which is emulating a
USB device via /dev/raw-gadget interface can be blocked by uninterruptible
blocking operations (e.g. mutex_lock()).

Please also note that (a) and (c) are not addressed. Regarding (c), we
should change the code to wait for only one device which contains the
image for resuming from hibernation. I don't know how to address (a), for
use of timeout for wait_for_device_probe() might result in loss of user
data in the image. Maybe we should require the userland to wait for the
image device before opening /dev/snapshot interface.

Link: https://syzkaller.appspot.com/bug?extid=358c9ab4c93da7b7238c [1]
Reported-by: syzbot 
Signed-off-by: Tetsuo Handa 
Tested-by: syzbot 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

PM: EM: Decrement policy counter

2022-06-09T08:30:09+00:00

[ Upstream commit c9d8923bfbcb63f15ea6cb2b5c8426fc3d96f643 ]

In commit e458716a92b57 ("PM: EM: Mark inefficiencies in CPUFreq"),
cpufreq_cpu_get() is called without a cpufreq_cpu_put(), permanently
increasing the reference counts of the policy struct.

Decrement the reference count once the policy struct is not used
anymore.

Fixes: e458716a92b57 ("PM: EM: Mark inefficiencies in CPUFreq")
Tested-by: Cristian Marussi 
Signed-off-by: Pierre Gondois 
Reviewed-by: Vincent Donnefort 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

Merge tag 'for-5.18/block-2022-03-18' of git://git.kernel.dk/linux-block

2022-03-21T23:48:55+00:00

Pull block updates from Jens Axboe:

 - BFQ cleanups and fixes (Yu, Zhang, Yahu, Paolo)

 - blk-rq-qos completion fix (Tejun)

 - blk-cgroup merge fix (Tejun)

 - Add offline error return value to distinguish it from an IO error on
   the device (Song)

 - IO stats fixes (Zhang, Christoph)

 - blkcg refcount fixes (Ming, Yu)

 - Fix for indefinite dispatch loop softlockup (Shin'ichiro)

 - blk-mq hardware queue management improvements (Ming)

 - sbitmap dead code removal (Ming, John)

 - Plugging merge improvements (me)

 - Show blk-crypto capabilities in sysfs (Eric)

 - Multiple delayed queue run improvement (David)

 - Block throttling fixes (Ming)

 - Start deprecating auto module loading based on dev_t (Christoph)

 - bio allocation improvements (Christoph, Chaitanya)

 - Get rid of bio_devname (Christoph)

 - bio clone improvements (Christoph)

 - Block plugging improvements (Christoph)

 - Get rid of genhd.h header (Christoph)

 - Ensure drivers use appropriate flush helpers (Christoph)

 - Refcounting improvements (Christoph)

 - Queue initialization and teardown improvements (Ming, Christoph)

 - Misc fixes/improvements (Barry, Chaitanya, Colin, Dan, Jiapeng,
   Lukas, Nian, Yang, Eric, Chengming)

* tag 'for-5.18/block-2022-03-18' of git://git.kernel.dk/linux-block: (127 commits)
  block: cancel all throttled bios in del_gendisk()
  block: let blkcg_gq grab request queue's refcnt
  block: avoid use-after-free on throttle data
  block: limit request dispatch loop duration
  block/bfq-iosched: Fix spelling mistake "tenative" -> "tentative"
  sr: simplify the local variable initialization in sr_block_open()
  block: don't merge across cgroup boundaries if blkcg is enabled
  block: fix rq-qos breakage from skipping rq_qos_done_bio()
  block: flush plug based on hardware and software queue order
  block: ensure plug merging checks the correct queue at least once
  block: move rq_qos_exit() into disk_release()
  block: do more work in elevator_exit
  block: move blk_exit_queue into disk_release
  block: move q_usage_counter release into blk_queue_release
  block: don't remove hctx debugfs dir from blk_mq_exit_queue
  block: move blkcg initialization/destroy into disk allocation/release handler
  sr: implement ->free_disk to simplify refcounting
  sd: implement ->free_disk to simplify refcounting
  sd: delay calling free_opal_dev
  sd: call sd_zbc_release_disk before releasing the scsi_device reference
  ...

PM: suspend: fix return value of __setup handler

2022-03-01T17:55:07+00:00

If an invalid option is given for "test_suspend=

PM: hibernate: fix __setup handler error handling

2022-03-01T17:51:11+00:00

If an invalid value is used in "resumedelay=", it is
silently ignored. Add a warning message and then let the __setup
handler return 1 to indicate that the kernel command line option
has been handled.

Fixes: 317cf7e5e85e3 ("PM / hibernate: convert simple_strtoul to kstrtoul")
Signed-off-by: Randy Dunlap 
Reported-by: Igor Zhbanov 
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Signed-off-by: Rafael J. Wysocki

PM: hibernate: Clean up non-kernel-doc comments

2022-03-01T15:20:46+00:00

Address the following W=1 kernel build warning:

kernel/power/swap.c:120: warning: This comment starts with '/**', but
isn't a kernel-doc comment. Refer
Documentation/doc-guide/kernel-doc.rst.

Reported-by: Abaci Robot 
Signed-off-by: Jiapeng Chong 
Signed-off-by: Rafael J. Wysocki

PM: hibernate: fix load_image_and_restore() error path

2022-02-16T18:47:52+00:00

As 'swsusp_check' open 'hib_resume_bdev', if call 'create_basic_memory_bitmaps'
failed, we need to close 'hib_resume_bdev' in 'load_image_and_restore' function.

Signed-off-by: Ye Bin 
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki

PM: s2idle: ACPI: Fix wakeup interrupts handling

2022-02-07T20:02:31+00:00

After commit e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race
related to the EC GPE") wakeup interrupts occurring immediately after
the one discarded by acpi_s2idle_wake() may be missed.  Moreover, if
the SCI triggers again immediately after the rearming in
acpi_s2idle_wake(), that wakeup may be missed too.

The problem is that pm_system_irq_wakeup() only calls pm_system_wakeup()
when pm_wakeup_irq is 0, but that's not the case any more after the
interrupt causing acpi_s2idle_wake() to run until pm_wakeup_irq is
cleared by the pm_wakeup_clear() call in s2idle_loop().  However,
there may be wakeup interrupts occurring in that time frame and if
that happens, they will be missed.

To address that issue first move the clearing of pm_wakeup_irq to
the point at which it is known that the interrupt causing
acpi_s2idle_wake() to tun will be discarded, before rearming the SCI
for wakeup.  Moreover, because that only reduces the size of the
time window in which the issue may manifest itself, allow
pm_system_irq_wakeup() to register two second wakeup interrupts in
a row and, when discarding the first one, replace it with the second
one.  [Of course, this assumes that only one wakeup interrupt can be
discarded in one go, but currently that is the case and I am not
aware of any plans to change that.]

Fixes: e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race related to the EC GPE")
Cc: 5.4+  # 5.4+
Signed-off-by: Rafael J. Wysocki

block: pass a block_device and opf to bio_alloc

2022-02-02T14:49:59+00:00

Pass the block_device and operation that we plan to use this bio for to
bio_alloc to optimize the assignment.  NULL/0 can be passed, both for the
passthrough case on a raw request_queue and to temporarily avoid
refactoring some nasty code.

Also move the gfp_mask argument after the nr_vecs argument for a much
more logical calling convention matching what most of the kernel does.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Chaitanya Kulkarni 
Link: https://lore.kernel.org/r/20220124091107.642561-18-hch@lst.de
Signed-off-by: Jens Axboe

block: remove genhd.h

2022-02-02T14:49:59+00:00

There is no good reason to keep genhd.h separate from the main blkdev.h
header that includes it.  So fold the contents of genhd.h into blkdev.h
and remove genhd.h entirely.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20220124093913.742411-4-hch@lst.de
Signed-off-by: Jens Axboe