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Linux kernel source tree
c03d982670
It's unclear what reference the initial vma kref reference refers to. A vma can have multiple weak references, the object vma list, the vm's bound list and the GT's closed_list, and the initial vma reference can be put from lookups of all these lists. With the current implementation this means that any holder of yet another vma refcount (currently only i915_gem_object_unbind()) needs to be holding two of either *) An object refcount, *) A vm open count *) A vma open count in order for us to not risk leaking a reference by having the initial vma reference being put twice. Address this by re-introducing i915_vma_destroy() which removes all weak references of the vma and *then* puts the initial vma refcount. This makes a strong vma reference hold on to the vma unconditionally. Perhaps a better name would be i915_vma_revoke() or i915_vma_zombify(), since other callers may still hold a refcount, but with the prospect of being able to replace the vma refcount with the object lock in the near future, let's stick with i915_vma_destroy(). Finally this commit fixes a race in that previously i915_vma_release() and now i915_vma_destroy() could destroy a vma without taking the vm->mutex after an advisory check that the vma mm_node was not allocated. This would race with the ungrab_vma() function creating a trace similar to the below one. This was fixed in one of the __i915_vma_put() callsites in commit |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.