Hi Andrew,
On 12/15/23 12:40 AM, Andrew Morton wrote:
On Thu, 14 Dec 2023 15:19:30 +0500 Muhammad Usama Anjum usama.anjum@collabora.com wrote:
The "locked-in-memory size" limit per process can be non-multiple of page_size. The mmap() fails if we try to allocate locked-in-memory with same size as the allowed limit if it isn't multiple of the page_size because mmap() rounds off the memory size to be allocated to next multiple of page_size.
Fix this by flooring the length to be allocated with mmap() to the previous multiple of the page_size.
I'd like to understand how this was noticed, what the ongoing effect might be, etc. To help decide which kernel version(s) need the patch.
This was getting triggered on KernelCI regularly because of different ulimit settings which wasn't multiple of the page_size. Find logs here: https://linux.kernelci.org/test/plan/id/657654bd8e81e654fae13532/ The bug in was present from the time test was first added.
Fixes: 76fe17ef588a ("secretmem: test: add basic selftest for memfd_secret(2)") Reported-by: "kernelci.org bot" bot@kernelci.org
Which is one of the reasons we're now placing a Closes: tag after a Reported-by:.
I was looking for email report from KernelCI. But I didn't find it. Not sure if we can do something like following: Closes: https://linux.kernelci.org/test/plan/id/657654bd8e81e654fae13532/