linux-toradex.git/kernel/power/hibernate.c, branch v6.7-rc4

PM: hibernate: Drop unused snapshot_test argument

2023-10-28T11:29:19+00:00

snapshot_test argument is now unused in swsusp_close() and
load_image_and_restore(). Drop it

CC: linux-pm@vger.kernel.org
Acked-by: Christoph Hellwig 
Acked-by: "Rafael J. Wysocki" 
Acked-by: Christian Brauner 
Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20230927093442.25915-17-jack@suse.cz
Signed-off-by: Christian Brauner

PM: hibernate: Fix the exclusive get block device in test_resume mode

2023-09-12T09:45:15+00:00

Commit 5904de0d735b ("PM: hibernate: Do not get block device exclusively
in test_resume mode") fixes a hibernation issue under test_resume mode.
That commit is supposed to open the block device in non-exclusive mode
when in test_resume. However the code does the opposite, which is against
its description.

In summary, the swap device is only opened exclusively by swsusp_check()
with its corresponding *close(), and must be in non test_resume mode.
This is to avoid the race condition that different processes scribble the
device at the same time. All the other cases should use non-exclusive mode.

Fix it by really disabling exclusive mode under test_resume.

Fixes: 5904de0d735b ("PM: hibernate: Do not get block device exclusively in test_resume mode")
Closes: https://lore.kernel.org/lkml/000000000000761f5f0603324129@google.com/
Reported-by: Pengfei Xu 
Signed-off-by: Chen Yu 
Tested-by: Chenzhou Feng 
Signed-off-by: Rafael J. Wysocki

PM: hibernate: fix resume_store() return value when hibernation not available

2023-08-07T09:41:11+00:00

On a laptop with hibernation set up but not actively used, and with
secure boot and lockdown enabled kernel, 6.5-rc1 gets stuck on boot with
the following repeated messages:

  A start job is running for Resume from hibernation using device /dev/system/swap (24s / no limit)
  lockdown_is_locked_down: 25311154 callbacks suppressed
  Lockdown: systemd-hiberna: hibernation is restricted; see man kernel_lockdown.7
  ...

Checking the resume code leads to commit cc89c63e2fe3 ("PM: hibernate:
move finding the resume device out of software_resume") which
inadvertently changed the return value from resume_store() to 0 when
!hibernation_available(). This apparently translates to userspace
write() returning 0 as in number of bytes written, and userspace looping
indefinitely in the attempt to write the intended value.

Fix this by returning the full number of bytes that were to be written,
as that's what was done before the commit.

Fixes: cc89c63e2fe3 ("PM: hibernate: move finding the resume device out of software_resume")
Signed-off-by: Vlastimil Babka 
Reviewed-by: Christoph Hellwig 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Rafael J. Wysocki

PM: hibernate: Fix writing maj:min to /sys/power/resume

2023-07-11T17:58:08+00:00

resume_store() first calls lookup_bdev() and after tries to handle
maj:min, but it does not reset the error before, hence if you will write
maj:min you will get ENOENT:

    # echo 259:2 >| /sys/power/resume
    bash: echo: write error: No such file or directory

This also should fix hiberation via systemd, since it uses this way.

Fixes: 1e8c813b083c4 ("PM: hibernate: don't use early_lookup_bdev in resume_store")
Signed-off-by: Azat Khuzhin 
Reviewed-by: Christoph Hellwig 
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki

block: use the holder as indication for exclusive opens

2023-06-12T14:04:04+00:00

The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder.  Remove the need to pass
FMODE_EXCL and just key off the exclusive open off a non-NULL holder.

For blkdev_put this requires adding the holder argument, which provides
better debug checking that only the holder actually releases the hold,
but at the same time allows removing the now superfluous mode argument.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Acked-by: Christian Brauner 
Acked-by: David Sterba 		[btrfs]
Acked-by: Jack Wang 		[rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-16-hch@lst.de
Signed-off-by: Jens Axboe

PM: hibernate: don't use early_lookup_bdev in resume_store

2023-06-05T16:57:40+00:00

resume_store is a sysfs attribute written during normal kernel runtime,
and it should not use the early_lookup_bdev API that bypasses all normal
path based permission checking, and might cause problems with certain
container environments renaming devices.

Switch to lookup_bdev, which does a normal path lookup instead, and fall
back to trying to parse a numeric dev_t just like early_lookup_bdev did.

Note that this strictly speaking changes the kernel ABI as the PARTUUID=
and PARTLABEL= style syntax is now not available during a running
systems.  They never were intended for that, but this breaks things
we'll have to figure out a way to make them available again.  But if
avoidable in any way I'd rather avoid that.

Fixes: 421a5fa1a6cf ("PM / hibernate: use name_to_dev_t to parse resume")
Signed-off-by: Christoph Hellwig 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20230531125535.676098-22-hch@lst.de
Signed-off-by: Jens Axboe

init: improve the name_to_dev_t interface

2023-06-05T16:56:46+00:00

name_to_dev_t has a very misleading name, that doesn't make clear
it should only be used by the early init code, and also has a bad
calling convention that doesn't allow returning different kinds of
errors.  Rename it to early_lookup_bdev to make the use case clear,
and return an errno, where -EINVAL means the string could not be
parsed, and -ENODEV means it the string was valid, but there was
no device found for it.

Also stub out the whole call for !CONFIG_BLOCK as all the non-block
root cases are always covered in the caller.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20230531125535.676098-14-hch@lst.de
Signed-off-by: Jens Axboe

PM: hibernate: move finding the resume device out of software_resume

2023-06-05T16:55:20+00:00

software_resume can be called either from an init call in the boot code,
or from sysfs once the system has finished booting, and the two
invocation methods this can't race with each other.

For the latter case we did just parse the suspend device manually, while
the former might not have one.  Split software_resume so that the search
only happens for the boot case, which also means the special lockdep
nesting annotation can go away as the system transition mutex can be
taken a little later and doesn't have the sysfs locking nest inside it.

Signed-off-by: Christoph Hellwig 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20230531125535.676098-5-hch@lst.de
Signed-off-by: Jens Axboe

PM: hibernate: remove the global snapshot_test variable

2023-06-05T16:55:20+00:00

Passing call dependent variable in global variables is a huge
antipattern.  Fix it up.

Signed-off-by: Christoph Hellwig 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20230531125535.676098-4-hch@lst.de
Signed-off-by: Jens Axboe

PM: hibernate: factor out a helper to find the resume device

2023-06-05T16:55:20+00:00

Split the logic to find the resume device out software_resume and into
a separate helper to start unwindig the convoluted goto logic.

Signed-off-by: Christoph Hellwig 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20230531125535.676098-3-hch@lst.de
Signed-off-by: Jens Axboe