On Thu, Sep 27, 2018 at 10:43:40PM +0800, zhong jiang wrote:
From: Alexey Dobriyan adobriyan@gmail.com
/* * cpu_partial determined the maximum number of objects * kept in the per cpu partial lists of a processor. */Can't be negative.
I hit a real issue that it will result in a large number of memory leak. Because Freeing slabs are in interrupt context. So it can trigger this issue. put_cpu_partial can be interrupted more than once. due to a union struct of lru and pobjects in struct page, when other core handles page->lru list, for eaxmple, remove_partial in freeing slab code flow, It will result in pobjects being a negative value(0xdead0000). Therefore, a large number of slabs will be added to per_cpu partial list.
I had posted the issue to community before. The detailed issue description is as follows.
Link: https://www.spinics.net/lists/kernel/msg2870979.html
After applying the patch, The issue is fixed. So the patch is a effective bugfix. It should go into stable.
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This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.
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