Dear maintainers, This series is following up on the last fix [2]. I thought I could forget about it with that. But, I was wrong because now this was realized as an incomplete solution -- my bad. Here is some context for this series: The last fix [3] has resolved the case when copying the initialized dynamic state from init_fpstate to the user buffer in __copy_xstate_to_uabi_buf(). (This was intended to resolve the fallout of the init_fpstate fix [1].) But, when copying the *non-initialized* dynamic state from the task xstate, the code [4] unconditionally retrieves the address in init_fpstate which is needless. Consequently, this triggers a false-positive warning as shown in [5] which meaninglessly confuses users. With these repetitive surgeries, a more solid and comprehensive solution is more helpful I thought. Considerably removing init_fpstate from this loop is not impossible here because dynamic states have an all-zeros init state. Then, zeroing the user buffer instead of retrieving init_fpstate resolves the issue and simplifies the code. These issues were discovered from the KVM execution with launching a guest and running the KVM self-test as __copy_xstate_to_uabi_buf() was called. But, the negligibly missing ptrace test could have disclosed them too. So that case is included here. Thanks, Chang [1] https://lore.kernel.org/lkml/20220824191223.1248-1-chang.seok.bae@xxxxxxxxx/ [2] https://lore.kernel.org/lkml/20221018221349.4196-1-chang.seok.bae@xxxxxxxxx/ [3] https://lore.kernel.org/lkml/20221021185844.13472-1-chang.seok.bae@xxxxxxxxx/ [4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/x86/kernel/fpu/xstate.c#n1156 [5] https://lore.kernel.org/kvm/20230221163655.920289-2-mizhang@xxxxxxxxxx/ Chang S. Bae (2): x86/fpu/xstate: Prevent false-positive warning in __copy_xstate_uabi_buf() selftests/x86/amx: Add a ptrace test arch/x86/kernel/fpu/xstate.c | 30 ++++----- tools/testing/selftests/x86/amx.c | 108 +++++++++++++++++++++++++++++- 2 files changed, 119 insertions(+), 19 deletions(-) base-commit: 7fa08de735e41001a70c8ca869b2b159d74c2339 -- 2.17.1
