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bfc3ae0566
This prevents the stack from accessing userspace objects while they
are being torn down.
One possible sequence of events:
- Userspace program exits
- ib_uverbs_cleanup_ucontext() runs, calling ib_destroy_qp(),
ib_destroy_cq(), etc. and releasing/freeing the UCQ
- The QP still has tasklets running, so it isn't destroyed yet
- The CQ is referenced by the QP, so the CQ isn't destroyed yet
- The UCQ is kfree()'d anyway
- A send work request completes
- rxe_send_complete() calls cq->ibcq.comp_handler()
- ib_uverbs_comp_handler() runs and crashes; the event queue is checked
for is_closed, but it has no way to check the ib_ucq_object before
accessing it
The reference counting on the CQ doesn't protect against this since the CQ
hasn't been destroyed yet.
There's no available interface to deregister the UCQ from the CQ, and it
didn't appear that attempting to add reference counting to the UCQ was
going to be a good way to go since this solution is much simpler.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.