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152c862c17
Since increase_top() does it's own READ_ONCE() on top_of_table, the
caller's prior READ_ONCE() could be inconsistent and the first time
through the loop we may actually already have the right level if two
threads are racing map.
In this case new_level will be left uninitialized.
Further all the exits from the loop have to either commit to the new top
or free any memory allocated so the early return must be a goto err_free.
Make it so the only break from the loop always sets new_level to the right
value and all other exits go to err_free. Use pts.level (the pts
represents the top we are stacking) within the loop instead of new_level.
Fixes: dcd6a011a8d5 ("iommupt: Add map_pages op")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/aRwgNW9PiW2j-Qwo@stanley.mountain
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.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 reStructuredText 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.