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

PM: hibernate: Fix crash when freeing invalid crypto compressor

2026-01-05T18:12:56Z

When crypto_alloc_acomp() fails, it returns an ERR_PTR value, not NULL. The cleanup code in save_compressed_image() and load_compressed_image() unconditionally calls crypto_free_acomp() without checking for ERR_PTR, which causes crypto_acomp_tfm() to dereference an invalid pointer and crash the kernel. This can be triggered when the compression algorithm is unavailable (e.g., CONFIG_CRYPTO_LZO not enabled). Fix by adding IS_ERR_OR_NULL() checks before calling crypto_free_acomp() and acomp_request_free(), similar to the existing kthread_stop() check. Fixes: b03d542c3c95 ("PM: hibernate: Use crypto_acomp interface") Signed-off-by: Malaya Kumar Rout Cc: 6.15+ # 6.15+ [ rjw: Added 2 empty code lines ] Link: https://patch.msgid.link/20251230115613.64080-1-mrout@redhat.com Signed-off-by: Rafael J. Wysocki

PM: hibernate: Extra cleanup of comments in swap handling code

2025-11-24T19:41:06Z

Continue recent cleanups of comments in the swap handling code. Unify the use of white space in the comments, drop some unuseful comments outside function bodies, and move some other comments into function bodies. No functional impact. Signed-off-by: Rafael J. Wysocki Link: https://patch.msgid.link/5943864.DvuYhMxLoT@rafael.j.wysocki

PM: hibernate: Clean up kernel-doc comment style usage

2025-11-17T19:16:56Z

Several static functions in kernel/power/swap.c were described using the kernel-doc comment style (/** ... */) even though they are not exported or referenced by generated documentation. This led to kernel-doc warnings and stylistic inconsistencies. Convert these unnecessary kernel-doc blocks to regular C comments, remove comment blocks that are no longer useful, relocate comments to more appropriate positions where needed, and fix a few "Return:" descriptions that were either missing or incorrectly formatted. No functional changes. Signed-off-by: Sunday Adelodun [ rjw: Subject adjustment, changelog edits, comment edits ] Link: https://patch.msgid.link/20251114220438.52448-1-adelodunolaoluwa@yahoo.com Signed-off-by: Rafael J. Wysocki

Merge back earlier material related to system sleep for 6.19

2025-11-17T15:55:55Z

PM: hibernate: Fix style issues in save_compressed_image()

2025-11-07T15:53:57Z

Address two issues indicated by checkpatch: - Trailing statements should be on next line. - Prefer 'unsigned int' to bare use of 'unsigned'. Signed-off-by: Mario Limonciello (AMD) [ rjw: Changelog edits ] Link: https://patch.msgid.link/20251106045158.3198061-4-superm1@kernel.org Signed-off-by: Rafael J. Wysocki

PM: hibernate: Use atomic64_t for compressed_size variable

2025-11-07T15:53:56Z

`compressed_size` can overflow, showing nonsensical values. Change from `atomic_t` to `atomic64_t` to prevent overflow. Fixes: a06c6f5d3cc9 ("PM: hibernate: Move to crypto APIs for LZO compression") Reported-by: Askar Safin Closes: https://lore.kernel.org/linux-pm/20251105180506.137448-1-safinaskar@gmail.com/ Signed-off-by: Mario Limonciello (AMD) Tested-by: Askar Safin Cc: 6.9+ # 6.9+ Link: https://patch.msgid.link/20251106045158.3198061-3-superm1@kernel.org Signed-off-by: Rafael J. Wysocki

PM: hibernate: Emit an error when image writing fails

2025-11-07T15:53:56Z

If image writing fails, a return code is passed up to the caller, but none of the callers log anything to the log and so the only record of it is the return code that userspace gets. Adjust the logging so that the image size and speed of writing is only emitted on success and if there is an error, it's saved to the logs. Fixes: a06c6f5d3cc9 ("PM: hibernate: Move to crypto APIs for LZO compression") Reported-by: Askar Safin Closes: https://lore.kernel.org/linux-pm/20251105180506.137448-1-safinaskar@gmail.com/ Signed-off-by: Mario Limonciello (AMD) Tested-by: Askar Safin Cc: 6.9+ # 6.9+ [ rjw: Added missing braces after "else", changelog edits ] Link: https://patch.msgid.link/20251106045158.3198061-2-superm1@kernel.org Signed-off-by: Rafael J. Wysocki

PM: hibernate: add sysfs interface for hibernate_compression_threads

2025-10-30T19:07:00Z

Add a sysfs attribute `/sys/power/hibernate_compression_threads` to allow runtime configuration of the number of threads used for compressing and decompressing hibernation images. The new sysfs interface enables dynamic adjustment at runtime: # cat /sys/power/hibernate_compression_threads 3 # echo 4 > /sys/power/hibernate_compression_threads This change provides greater flexibility for debugging and performance tuning of hibernation without requiring a reboot. Signed-off-by: Xueqin Luo Link: https://patch.msgid.link/c68c62f97fabf32507b8794ad8c16cd22ee656ac.1761046167.git.luoxueqin@kylinos.cn Signed-off-by: Rafael J. Wysocki

PM: hibernate: make compression threads configurable

2025-10-30T19:07:00Z

The number of compression/decompression threads has a direct impact on hibernate image generation and resume latency. Using more threads can reduce overall resume time, but on systems with fewer CPU cores it may also introduce contention and reduce efficiency. Performance was evaluated on an 8-core ARM system, averaged over 10 runs: Threads Hibernate(s) Resume(s) -------------------------------- 3 12.14 18.86 4 12.28 17.48 5 11.09 16.77 6 11.08 16.44 With 5–6 threads, resume latency improves by approximately 12% compared to the default 3-thread configuration, with negligible impact on hibernate time. Introduce a new kernel parameter `hibernate_compression_threads=` that allows users and integrators to tune the number of compression/decompression threads at boot. This provides a way to balance performance and CPU utilization across a wide range of hardware without recompiling the kernel. Signed-off-by: Xueqin Luo Link: https://patch.msgid.link/f24b3ca6416e230a515a154ed4c121d72a7e05a6.1761046167.git.luoxueqin@kylinos.cn Signed-off-by: Rafael J. Wysocki

PM: hibernate: dynamically allocate crc->unc_len/unc for configurable threads

2025-10-30T19:07:00Z

Convert crc->unc_len and crc->unc from fixed-size arrays to dynamically allocated arrays, sized according to the actual number of threads selected at runtime. This removes the fixed limit imposed by CMP_THREADS. Signed-off-by: Xueqin Luo Link: https://patch.msgid.link/b5db63bb95729482d2649b12d3a11cb7547b7fcc.1761046167.git.luoxueqin@kylinos.cn Signed-off-by: Rafael J. Wysocki