6744a030d8
On driver unload any pending descriptors are flushed and pending
DMA descriptors are explicitly completed:
idxd_dmaengine_drv_remove() ->
drv_disable_wq() ->
idxd_wq_free_irq() ->
idxd_flush_pending_descs() ->
idxd_dma_complete_txd()
With this done during driver unload any remaining descriptor is
likely stuck and can be dropped. Even so, the descriptor may still
have a callback set that could no longer be accessible. An
example of such a problem is when the dmatest fails and the dmatest
module is unloaded. The failure of dmatest leaves descriptors with
dma_async_tx_descriptor::callback pointing to code that no longer
exist. This causes a page fault as below at the time the IDXD driver
is unloaded when it attempts to run the callback:
BUG: unable to handle page fault for address: ffffffffc0665190
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
Fix this by clearing the callback pointers on the transmit
descriptors only when workqueue is disabled.
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 | ||
| .cocciconfig | ||
| .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
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text 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.