kernel/linux.git/fs/pstore/Kconfig, branch linux-7.1.y

pstore: Replace crypto API compression with zlib_deflate library calls

2023-07-17T23:08:58+00:00

Pstore supports compression using a variety of algorithms exposed by the crypto API. This uses the deprecated comp (as opposed to scomp/acomp) API, and so we should stop using that, and either move to the new API, or switch to a different approach entirely. Given that we only compress ASCII text in pstore, and considering that this happens when the system is likely to be in an unstable state, the flexibility that the complex crypto API provides does not outweigh its impact on the risk that we might encounter additional problems when trying to commit the kernel log contents to the pstore backend. So let's switch [back] to the zlib deflate library API, and remove all the complexity that really has no place in a low-level diagnostic facility. Note that, while more modern compression algorithms have been added to the kernel in recent years, the code size of zlib deflate is substantially smaller than, e.g., zstd, while its performance in terms of compression ratio is comparable for ASCII text, and speed is deemed irrelevant in this context. Note that this means that compressed pstore records may no longer be accessible after a kernel upgrade, but this has never been part of the contract. (The choice of compression algorithm is not stored in the pstore records either) Tested-by: "Guilherme G. Piccoli" # Steam Deck Signed-off-by: Ard Biesheuvel Reviewed-by: Eric Biggers Link: https://lore.kernel.org/r/20230712162332.2670437-3-ardb@kernel.org Signed-off-by: Kees Cook

pstore: Make sure CONFIG_PSTORE_PMSG selects CONFIG_RT_MUTEXES

2022-12-23T18:33:27+00:00

In commit 76d62f24db07 ("pstore: Switch pmsg_lock to an rt_mutex to avoid priority inversion") I changed a lock to an rt_mutex. However, its possible that CONFIG_RT_MUTEXES is not enabled, which then results in a build failure, as the 0day bot detected: https://lore.kernel.org/linux-mm/202212211244.TwzWZD3H-lkp@intel.com/ Thus this patch changes CONFIG_PSTORE_PMSG to select CONFIG_RT_MUTEXES, which ensures the build will not fail. Cc: Wei Wang Cc: Midas Chien Cc: Connor O'Brien Cc: Kees Cook Cc: Anton Vorontsov Cc: Colin Cross Cc: Tony Luck Cc: kernel test robot Cc: kernel-team@android.com Fixes: 76d62f24db07 ("pstore: Switch pmsg_lock to an rt_mutex to avoid priority inversion") Reported-by: kernel test robot Signed-off-by: John Stultz Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221221051855.15761-1-jstultz@google.com

Revert "mark pstore-blk as broken"

2021-11-17T00:23:42+00:00

This reverts commit d07f3b081ee632268786601f55e1334d1f68b997. pstore-blk was fixed to avoid the unwanted APIs in commit 7bb9557b48fc ("pstore/blk: Use the normal block device I/O path"), which landed in the same release as the commit adding BROKEN. Cc: Jens Axboe Cc: Christoph Hellwig Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20211116181559.3975566-1-keescook@chromium.org Signed-off-by: Jens Axboe

mark pstore-blk as broken

2021-06-14T14:26:03+00:00

pstore-blk just pokes directly into the pagecache for the block device without going through the file operations for that by faking up it's own file operations that do not match the block device ones. As this breaks the control of the block layer of it's page cache, and even now just works by accident only the best thing is to just disable this driver. Fixes: 17639f67c1d6 ("pstore/blk: Introduce backend for block devices") Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210608161327.1537919-1-hch@lst.de Signed-off-by: Jens Axboe

pstore: Move kmsg_bytes default into Kconfig

2020-12-01T20:09:17+00:00

While kmsg_bytes can be set for pstore via mount, if a crash occurs before the mount only partial console log will be stored as kmsg_bytes defaults to a potentially different hardcoded value in the kernel (PSTORE_DEFAULT_KMSG_BYTES). This makes it impossible to analyze valuable post-mortem data especially on the embedded development or in the process of bringing up new boards. Change this value to be a Kconfig option with the default of old PSTORE_DEFAULT_KMSG_BYTES Signed-off-by: Vasile-Laurentiu Stanimir Signed-off-by: Kees Cook

Documentation: Add details for pstore/blk

2020-05-30T17:34:03+00:00

Add details on using pstore/blk, the new backend of pstore to record dumps to block devices, in Documentation/admin-guide/pstore-blk.rst Signed-off-by: WeiXiong Liao Link: https://lore.kernel.org/lkml/20200511233229.27745-7-keescook@chromium.org/ Signed-off-by: Kees Cook

pstore/zone,blk: Add ftrace frontend support

2020-05-30T17:34:03+00:00

Support backend for ftrace. To enable ftrace backend, just make ftrace_size be greater than 0 and a multiple of 4096. Signed-off-by: WeiXiong Liao Link: https://lore.kernel.org/lkml/20200511233229.27745-6-keescook@chromium.org/ Co-developed-by: Colin Ian King Signed-off-by: Colin Ian King Link: https://lore.kernel.org/lkml/20200512170719.221514-1-colin.king@canonical.com Signed-off-by: Kees Cook

pstore/zone,blk: Add console frontend support

2020-05-30T17:34:03+00:00

Support backend for console. To enable console backend, just make console_size be greater than 0 and a multiple of 4096. Signed-off-by: WeiXiong Liao Link: https://lore.kernel.org/lkml/20200511233229.27745-5-keescook@chromium.org/ Signed-off-by: Kees Cook

pstore/zone,blk: Add support for pmsg frontend

2020-05-30T17:34:03+00:00

Add pmsg support to pstore/blk (through pstore/zone). To enable, pmsg_size must be greater than 0 and a multiple of 4096. Signed-off-by: WeiXiong Liao Link: https://lore.kernel.org/lkml/20200511233229.27745-4-keescook@chromium.org/ Co-developed-by: Colin Ian King Signed-off-by: Colin Ian King Link: https://lore.kernel.org/lkml/20200512171932.222102-1-colin.king@canonical.com Co-developed-by: Kees Cook Signed-off-by: Kees Cook

pstore/blk: Introduce backend for block devices

2020-05-30T17:34:03+00:00

pstore/blk is similar to pstore/ram, but uses a block device as the storage rather than persistent ram. The pstore/blk backend solves two common use-cases that used to preclude using pstore/ram: - not all devices have a battery that could be used to persist regular RAM across power failures. - most embedded intelligent equipment have no persistent ram, which increases costs, instead preferring cheaper solutions, like block devices. pstore/blk provides separate configurations for the end user and for the block drivers. User configuration determines how pstore/blk operates, such as record sizes, max kmsg dump reasons, etc. These can be set by Kconfig and/or module parameters, but module parameter have priority over Kconfig. Driver configuration covers all the details about the target block device, such as total size of the device and how to perform read/write operations. These are provided by block drivers, calling pstore_register_blkdev(), including an optional panic_write callback used to bypass regular IO APIs in an effort to avoid potentially destabilized kernel code during a panic. Signed-off-by: WeiXiong Liao Link: https://lore.kernel.org/lkml/20200511233229.27745-3-keescook@chromium.org/ Co-developed-by: Kees Cook Signed-off-by: Kees Cook