Messages in this thread | | | Subject | arch_set_user_pkey_access only works on the current task_struct | From | Jiashuo Liang <> | Date | Sat, 05 Jun 2021 21:10:28 +0800 |
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Hi,
I am learning the kernel implementation of the x86 PKU feature. I find the arch_set_user_pkey_access function in arch/x86/kernel/fpu/xstate.c does not use its first parameter. So it is perhaps a bug?
The arch_set_user_pkey_access function is supposed to set the PKRU register for the task_struct specified by its first parameter tsk. But it is only implemented for the current task_struct.
Fortunately, it has been called only with current task_struct in the kernel code, so it appears to be okay. However, it can introduce bugs in the future because people may expect it working on other task_struct.
This commit seems to be related: b79daf8589921 ("x86/mm/pkeys: Fix compact mode by removing protection keys' XSAVE buffer manipulation").
Thank you! liangjs
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