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c23981df66
In the extreme case of host counters multiplexing and contention, the
perf_event requested by the guest's pebs counter is not allocated to any
actual physical counter, in which case hw.idx is bookkept as -1,
resulting in an out-of-bounds access to host_cross_mapped_mask.
Fixes: 854250329c ("KVM: x86/pmu: Disable guest PEBS temporarily in two rare situations")
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20220831085328.45489-2-likexu@tencent.com
[sean: expand comment to explain how a negative idx can be encountered]
Signed-off-by: Sean Christopherson <seanjc@google.com>
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.