linux-stable.git/kernel/power/swap.c, branch linux-6.6.y

PM: hibernate: Don't ignore return from set_memory_ro()

2026-04-02T11:07:22+00:00

[ Upstream commit f4311756a83fb01c28a9bf841cbb7eb2b318eebf ]

set_memory_ro() and set_memory_rw() can fail, leaving memory
unprotected.

Take the returned value into account and abort in case of
failure.

Signed-off-by: Christophe Leroy 
Reviewed-by: Kees Cook 
Signed-off-by: Rafael J. Wysocki 
Stable-dep-of: 734eba62cd32 ("PM: hibernate: Drain trailing zero pages on userspace restore")
Signed-off-by: Sasha Levin

PM: hibernate: Enforce ordering during image compression/decompression

2024-02-01T00:18:49+00:00

commit 71cd7e80cfde548959952eac7063aeaea1f2e1c6 upstream.

An S4 (suspend to disk) test on the LoongArch 3A6000 platform sometimes
fails with the following error messaged in the dmesg log:

	Invalid LZO compressed length

That happens because when compressing/decompressing the image, the
synchronization between the control thread and the compress/decompress/crc
thread is based on a relaxed ordering interface, which is unreliable, and the
following situation may occur:

CPU 0					CPU 1
save_image_lzo				lzo_compress_threadfn
					  atomic_set(&d->stop, 1);
  atomic_read(&data[thr].stop)
  data[thr].cmp = data[thr].cmp_len;
	  				  WRITE data[thr].cmp_len

Then CPU0 gets a stale cmp_len and writes it to disk. During resume from S4,
wrong cmp_len is loaded.

To maintain data consistency between the two threads, use the acquire/release
variants of atomic set and read operations.

Fixes: 081a9d043c98 ("PM / Hibernate: Improve performance of LZO/plain hibernation, checksum image")
Cc: All applicable 
Signed-off-by: Hongchen Zhang 
Co-developed-by: Weihao Li 
Signed-off-by: Weihao Li 
[ rjw: Subject rewrite and changelog edits ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM: hibernate: Rename function parameter from snapshot_test to exclusive

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

Several functions reply on snapshot_test to decide whether to
open the resume device exclusively. However there is no strict
connection between the snapshot_test and the open mode. Rename
the 'snapshot_test' input parameter to 'exclusive' to better reflect
the use case.

No functional change is expected.

Signed-off-by: Chen Yu 
Signed-off-by: Rafael J. Wysocki

block: replace fmode_t with a block-specific type for block open flags

2023-06-12T14:04:05+00:00

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE.  Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.

Signed-off-by: Christoph Hellwig 
Acked-by: Jack Wang 		[rnbd]
Reviewed-by: Hannes Reinecke 
Reviewed-by: Christian Brauner 
Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de
Signed-off-by: Jens Axboe

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

swsusp: don't pass a stack address to blkdev_get_by_path

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

holder is just an on-stack pointer that can easily be reused by other calls,
replace it with a static variable that doesn't change.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Acked-by: Rafael J. Wysocki 
Link: https://lore.kernel.org/r/20230608110258.189493-12-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

block: introduce holder ops

2023-06-05T16:53:04+00:00

Add a new blk_holder_ops structure, which is passed to blkdev_get_by_* and
installed in the block_device for exclusive claims.  It will be used to
allow the block layer to call back into the user of the block device for
thing like notification of a removed device or a device resize.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Acked-by: Dave Chinner 
Reviewed-by: Dave Chinner 
Link: https://lore.kernel.org/r/20230601094459.1350643-10-hch@lst.de
Signed-off-by: Jens Axboe

PM: hibernate: Do not get block device exclusively in test_resume mode

2023-04-27T17:00:28+00:00

The system refused to do a test_resume because it found that the
swap device has already been taken by someone else. Specifically,
the swsusp_check()->blkdev_get_by_dev(FMODE_EXCL) is supposed to
do this check.

Steps to reproduce:
 dd if=/dev/zero of=/swapfile bs=$(cat /proc/meminfo |
       awk '/MemTotal/ {print $2}') count=1024 conv=notrunc
 mkswap /swapfile
 swapon /swapfile
 swap-offset /swapfile
 echo 34816 > /sys/power/resume_offset
 echo test_resume > /sys/power/disk
 echo disk > /sys/power/state

 PM: Using 3 thread(s) for compression
 PM: Compressing and saving image data (293150 pages)...
 PM: Image saving progress:   0%
 PM: Image saving progress:  10%
 ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
 ata1.00: configured for UDMA/100
 ata2: SATA link down (SStatus 0 SControl 300)
 ata5: SATA link down (SStatus 0 SControl 300)
 ata6: SATA link down (SStatus 0 SControl 300)
 ata3: SATA link down (SStatus 0 SControl 300)
 ata4: SATA link down (SStatus 0 SControl 300)
 PM: Image saving progress:  20%
 PM: Image saving progress:  30%
 PM: Image saving progress:  40%
 PM: Image saving progress:  50%
 pcieport 0000:00:02.5: pciehp: Slot(0-5): No device found
 PM: Image saving progress:  60%
 PM: Image saving progress:  70%
 PM: Image saving progress:  80%
 PM: Image saving progress:  90%
 PM: Image saving done
 PM: hibernation: Wrote 1172600 kbytes in 2.70 seconds (434.29 MB/s)
 PM: S|
 PM: hibernation: Basic memory bitmaps freed
 PM: Image not found (code -16)

This is because when using the swapfile as the hibernation storage,
the block device where the swapfile is located has already been mounted
by the OS distribution(usually mounted as the rootfs). This is not
an issue for normal hibernation, because software_resume()->swsusp_check()
happens before the block device(rootfs) mount. But it is a problem for the
test_resume mode. Because when test_resume happens, the block device has
been mounted already.

Thus remove the FMODE_EXCL for test_resume mode. This would not be a
problem because in test_resume stage, the processes have already been
frozen, and the race condition described in
Commit 39fbef4b0f77 ("PM: hibernate: Get block device exclusively in swsusp_check()")
is unlikely to happen.

Fixes: 39fbef4b0f77 ("PM: hibernate: Get block device exclusively in swsusp_check()")
Reported-by: Yifan Li 
Suggested-by: Pavankumar Kondeti 
Tested-by: Pavankumar Kondeti 
Tested-by: Wendy Wang 
Signed-off-by: Chen Yu 
Signed-off-by: Rafael J. Wysocki

PM: hibernate: swap: don't use /** for non-kernel-doc comments

2023-01-20T13:49:48+00:00

kernel-doc complains about multiple occurrences of "/**" being used
for something that is not a kernel-doc comment, so change all of these
to just use "/*" comment style.

The warning message for all of these is:

FILE:LINE: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

kernel/power/swap.c:585: warning: ...
Structure used for CRC32.
kernel/power/swap.c:600: warning: ...
 * CRC32 update function that runs in its own thread.
kernel/power/swap.c:627: warning: ...
 * Structure used for LZO data compression.
kernel/power/swap.c:644: warning: ...
 * Compression function that runs in its own thread.
kernel/power/swap.c:952: warning: ...
 *      The following functions allow us to read data using a swap map
kernel/power/swap.c:1111: warning: ...
 * Structure used for LZO data decompression.
kernel/power/swap.c:1127: warning: ...
 * Decompression function that runs in its own thread.

Also correct one spello/typo.

Signed-off-by: Randy Dunlap 
Signed-off-by: Rafael J. Wysocki