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77ced98f0f
The fix implemented in commit4ec10268ed("mm, slab: unlink slabinfo, sysfs and debugfs immediately") caused a subtle side effect due to which while destroying the kmem cache, the code path would never get into sysfs_slab_release() function even though SLAB_SUPPORTS_SYSFS is defined and slab state is FULL. Due to this side effect, we would never release kobject defined for kmem cache and leak the associated memory. The issue here's with the use of __is_defined() macro in kmem_cache_ release(). The __is_defined() macro expands to __take_second_arg( arg1_or_junk 1, 0). If "arg1_or_junk" is defined to 1 then it expands to __take_second_arg(0, 1, 0) and returns 1. If "arg1_or_junk" is NOT defined to any value then it expands to __take_second_arg(... 1, 0) and returns 0. In this particular issue, SLAB_SUPPORTS_SYSFS is defined without any associated value and that causes __is_defined(SLAB_SUPPORTS_SYSFS) to always evaluate to 0 and hence it would never invoke sysfs_slab_release(). This patch helps fix this issue by defining SLAB_SUPPORTS_SYSFS to 1. Fixes:4ec10268ed("mm, slab: unlink slabinfo, sysfs and debugfs immediately") Reported-by: Yi Zhang <yi.zhang@redhat.com> Closes: https://lore.kernel.org/all/CAHj4cs9YCCcfmdxN43-9H3HnTYQsRtTYw1Kzq-L468GfLKAENA@mail.gmail.com/ Signed-off-by: Nilay Shroff <nilay@linux.ibm.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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.