Re: [PATCH v2 0/2] x86/traps: Fix DR6/DR7 initialization

[Sohil Mehta]

On 6/17/2025 12:32 AM, Xin Li (Intel) wrote:
> Sohil reported seeing a split lock warning when running a test that
> generates userspace #DB:
> 
>   x86/split lock detection: #DB: sigtrap_loop_64/4614 took a bus_lock trap at address: 0x4011ae
> 

The following patches fix the issue for me.

Tested-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>

> 
> Xin Li (Intel) (2):
>   x86/traps: Initialize DR6 by writing its architectural reset value
>   x86/traps: Initialize DR7 by writing its architectural reset value
> 
>  arch/x86/include/asm/debugreg.h      | 14 ++++++++----
>  arch/x86/include/asm/kvm_host.h      |  2 +-
>  arch/x86/include/uapi/asm/debugreg.h |  7 +++++-
>  arch/x86/kernel/cpu/common.c         | 17 ++++++--------
>  arch/x86/kernel/kgdb.c               |  2 +-
>  arch/x86/kernel/process_32.c         |  2 +-
>  arch/x86/kernel/process_64.c         |  2 +-
>  arch/x86/kernel/traps.c              | 34 +++++++++++++++++-----------
>  arch/x86/kvm/x86.c                   |  4 ++--
>  9 files changed, 50 insertions(+), 34 deletions(-)
> 
> 
> base-commit: 594902c986e269660302f09df9ec4bf1cf017b77