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Linux kernel source tree
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Valve reported a kernel crash on Ubuntu 18.04 when disconnecting a DS4 gamepad while rumble is enabled. This issue is reproducible with a frequency of 1 in 3 times in the game Borderlands 2 when using an automatic weapon, which triggers many rumble operations. We found the issue to be a race condition between sony_remove and the final device destruction by the HID / input system. The problem was that sony_remove didn't clean some of its work_item state in "struct sony_sc". After sony_remove work, the corresponding evdev node was around for sufficient time for applications to still queue rumble work after "sony_remove". On pre-4.19 kernels the race condition caused a kernel crash due to a NULL-pointer dereference as "sc->output_report_dmabuf" got freed during sony_remove. On newer kernels this crash doesn't happen due the buffer now being allocated using devm_kzalloc. However we can still queue work, while the driver is an undefined state. This patch fixes the described problem, by guarding the work_item "state_worker" with an initialized variable, which we are setting back to 0 on cleanup. Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com> CC: stable@vger.kernel.org Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
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| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
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| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
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| Kbuild | ||
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| 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.