4ebd9a5ca4
With the latest mm-unstable, setting the iaa_crypto sync_mode to 'async'
causes crypto testmgr.c test_acomp() failure and dmesg call traces, and
zswap being unable to use 'deflate-iaa' as a compressor:
echo async > /sys/bus/dsa/drivers/crypto/sync_mode
[ 255.271030] zswap: compressor deflate-iaa not available
[ 369.960673] INFO: task cryptomgr_test:4889 blocked for more than 122 seconds.
[ 369.970127] Not tainted 6.13.0-rc1-mm-unstable-12-16-2024+ #324
[ 369.977411] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 369.986246] task:cryptomgr_test state:D stack:0 pid:4889 tgid:4889 ppid:2 flags:0x00004000
[ 369.986253] Call Trace:
[ 369.986256] <TASK>
[ 369.986260] __schedule+0x45c/0xfa0
[ 369.986273] schedule+0x2e/0xb0
[ 369.986277] schedule_timeout+0xe7/0x100
[ 369.986284] ? __prepare_to_swait+0x4e/0x70
[ 369.986290] wait_for_completion+0x8d/0x120
[ 369.986293] test_acomp+0x284/0x670
[ 369.986305] ? __pfx_cryptomgr_test+0x10/0x10
[ 369.986312] alg_test_comp+0x263/0x440
[ 369.986315] ? sched_balance_newidle+0x259/0x430
[ 369.986320] ? __pfx_cryptomgr_test+0x10/0x10
[ 369.986323] alg_test.part.27+0x103/0x410
[ 369.986326] ? __schedule+0x464/0xfa0
[ 369.986330] ? __pfx_cryptomgr_test+0x10/0x10
[ 369.986333] cryptomgr_test+0x20/0x40
[ 369.986336] kthread+0xda/0x110
[ 369.986344] ? __pfx_kthread+0x10/0x10
[ 369.986346] ret_from_fork+0x2d/0x40
[ 369.986355] ? __pfx_kthread+0x10/0x10
[ 369.986358] ret_from_fork_asm+0x1a/0x30
[ 369.986365] </TASK>
This happens because the only async polling without interrupts that
iaa_crypto currently implements is with the 'sync' mode. With 'async',
iaa_crypto calls to compress/decompress submit the descriptor and return
-EINPROGRESS, without any mechanism in the driver to poll for
completions. Hence callers such as test_acomp() in crypto/testmgr.c or
zswap, that wrap the calls to crypto_acomp_compress() and
crypto_acomp_decompress() in synchronous wrappers, will block
indefinitely. Even before zswap can notice this problem, the crypto
testmgr.c's test_acomp() will fail and prevent registration of
"deflate-iaa" as a valid crypto acomp algorithm, thereby disallowing the
use of "deflate-iaa" as a zswap compress (zswap will fall-back to the
default compressor in this case).
To fix this issue, this patch modifies the iaa_crypto sync_mode set
function to treat 'async' equivalent to 'sync', so that the correct and
only supported driver async polling without interrupts implementation is
enabled, and zswap can use 'deflate-iaa' as the compressor.
Hence, with this patch, this is what will happen:
echo async > /sys/bus/dsa/drivers/crypto/sync_mode
cat /sys/bus/dsa/drivers/crypto/sync_mode
sync
There are no crypto/testmgr.c test_acomp() errors, no call traces and zswap
can use 'deflate-iaa' without any errors. The iaa_crypto documentation has
also been updated to mention this caveat with 'async' and what to expect
with this fix.
True iaa_crypto async polling without interrupts is enabled in patch
"crypto: iaa - Implement batch_compress(), batch_decompress() API in
iaa_crypto." [1] which is under review as part of the "zswap IAA compress
batching" patch-series [2]. Until this is merged, we would appreciate it if
this current patch can be considered for a hotfix.
[1]: https://patchwork.kernel.org/project/linux-mm/patch/20241221063119.29140-5-kanchana.p.sridhar@intel.com/
[2]: https://patchwork.kernel.org/project/linux-mm/list/?series=920084
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.