This series fixes two problems with KGDB on x86 concerning the removal
of breakpoints, causing the kernel to hang.  Note that breakpoint
removal is not only performed when explicitly deleting a breakpoint,
but also happens before continuing execution or single stepping.

Florian Rommel (2):
  x86/kgdb: convert early breakpoints to poke breakpoints
  x86/kgdb: fix hang on failed breakpoint removal

 arch/x86/kernel/kgdb.c    | 38 ++++++++++++++++++++++++++++++++++++++
 include/linux/kgdb.h      |  3 +++
 init/main.c               |  1 +
 kernel/debug/debug_core.c |  7 ++++++-
 4 files changed, 48 insertions(+), 1 deletion(-)

-- 
2.46.0

On Mon, 12 Aug 2024 01:22:06 +0200 Florian Rommel <mail@florommel.de> wrote:

> This series fixes two problems with KGDB on x86 concerning the removal
> of breakpoints, causing the kernel to hang.  Note that breakpoint
> removal is not only performed when explicitly deleting a breakpoint,
> but also happens before continuing execution or single stepping.

Neat.  It would be nice to fix earlier kernels; for that it is
desirable to identify a Fixes: target.  From a quick look it appears
this issue is more than a decade old, in which case I don't believe a
Fixes: is needed - our request becomes "please backport to everything".

On Tue, 2024-08-13 at 17:10 -0700, Andrew Morton wrote:
> On Mon, 12 Aug 2024 01:22:06 +0200 Florian Rommel <mail@florommel.de> wrote:
> 
> > This series fixes two problems with KGDB on x86 concerning the removal
> > of breakpoints, causing the kernel to hang.  Note that breakpoint
> > removal is not only performed when explicitly deleting a breakpoint,
> > but also happens before continuing execution or single stepping.
> 
> Neat.  It would be nice to fix earlier kernels; for that it is
> desirable to identify a Fixes: target.  From a quick look it appears
> this issue is more than a decade old, in which case I don't believe a
> Fixes: is needed - our request becomes "please backport to everything".
> 

Thanks. There is already a v2 (due to my negligence on the details) and
a bit of discussion:
https://lore.kernel.org/all/20240812174338.363838-1-mail@florommel.de/

Rgeards,
Florian