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The function for allocating and initialize a 'struct damos' object, damon_new_scheme(), is not initializing damos->walk_completed field. Only damos_walk_complete() is setting the field. Hence the field will be eventually set and used correctly from second damos_walk() call for the scheme. But the first damos_walk() could mistakenly not walk on the regions. Actually, a common usage of DAMOS for taking an access pattern snapshot is installing a monitoring-purpose DAMOS scheme, doing damos_walk() to retrieve the snapshot, and then removing the scheme. DAMON user-space tool (damo) also gets runtime snapshot in the way. Hence the problem can continuously happen in such use cases. Initialize it properly in the allocation function. Link: https://lkml.kernel.org/r/20250228174450.41472-1-sj@kernel.org Fixes: bf0eaba0ff9c ("mm/damon/core: implement damos_walk()") Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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.
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