Re: [PATCH 0/3] hw_breakpoint: Fix and simplify local address updates for wprobe

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Sun, 26 Jul 2026 20:22:29 +0800
Jinchao Wang <wangjinchao600@gmail.com> wrote:

> Hi Masami,
> 
> While reviewing wprobe v10, I prepared three patches to fix and simplify
> the HWBP support required by wprobe.

Hi Jinchao,

Thanks for the series!

> 
> This series is based on linux-trace/probes/for-next, the same base used by
> wprobe v10. It is intended to replace patches 5-7 in v10, so it should not
> be applied on top of topic/wprobe-v2.

OK, let me replace it with this series.
I'll also update wprobe side and make it v11.

> 
> Patch 1 fixes the x86 HWBP slot and DR7 races when an operation is
> interrupted by an NMI.
> 
> Patch 2 adds arch_modify_local_hw_breakpoint_addr(), which updates only
> the watched address of an installed breakpoint on the local CPU.
> 
> Patch 3 adds the matching generic modify_local_hw_breakpoint_addr() API.
> It keeps the original patch structure and Masami's authorship, while
> removing attribute parsing, type/length updates and rollback.
> 
> With the address-only interface, the install/uninstall refactoring in the
> old patch 5 is no longer needed.

OK.

> 
> I can take care of follow-up maintenance related to fast local HWBP
> watched-address updates.
> 
> The patches passed checkpatch and the relevant x86_32 and x86_64 object
> builds.

Thanks!

> 
> Jinchao Wang (2):
>   x86/hw_breakpoints: Make DR7 updates NMI safe
>   x86/hw_breakpoints: Add arch_modify_local_hw_breakpoint_addr() API
> 
> Masami Hiramatsu (Google) (1):
>   HWBP: Add modify_local_hw_breakpoint_addr() API
> 
>  arch/Kconfig                         |   8 ++
>  arch/x86/Kconfig                     |   1 +
>  arch/x86/include/asm/debugreg.h      |  36 ++++++---
>  arch/x86/include/asm/hw_breakpoint.h |   2 +
>  arch/x86/kernel/cpu/mce/core.c       |  20 +++--
>  arch/x86/kernel/hw_breakpoint.c      | 114 ++++++++++++++++-----------
>  arch/x86/kernel/nmi.c                |  10 ++-
>  arch/x86/kernel/traps.c              |  10 ++-
>  include/linux/hw_breakpoint.h        |   6 ++
>  kernel/events/hw_breakpoint.c        |  30 +++++++
>  10 files changed, 166 insertions(+), 71 deletions(-)
> 
> 
> base-commit: 1a416ae446afa42d2d8500ce25bd61c564508721
> -- 
> 2.53.0


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>