RE: [PATCH v4 1/1] gdb: avoid conversion of SIGSEGV to SIGTRAP on user breakpoints

Thank you, Baris.

 I discovered this too *after* I posted. I'll make sure it's updated once Andrew approves again.

Thanks
Klaus

> -----Original Message-----
> From: Aktemur, Baris <[email protected]>
> Sent: Friday, July 17, 2026 11:17 AM
> To: Gerlicher, Klaus <[email protected]>; gdb-
> [email protected]
> Cc: [email protected]
> Subject: RE: [PATCH v4 1/1] gdb: avoid conversion of SIGSEGV to SIGTRAP on
> user breakpoints
> 
> AMD General
> 
> Hi Klaus,
> 
> On Friday, July 17, 2026 9:45 AM, Klaus Gerlicher wrote:
> > GDB converts signals GDB_SIGNAL_ILL, GDB_SIGNAL_SEGV and
> GDB_SIGNAL_EMT to
> > GDB_SIGNAL_TRAP if a breakpoint is inserted at the fault location.  If, due
> > to imprecise page fault reporting, a breakpoint is at the same address as
> > the fault address, this signal would always be reported as
> GDB_SIGNAL_TRAP.
> >
> > Add a new gdbarch function, imprecise_pagefault_reporting, that allows the
> > signal conversion from GDB_SIGNAL_SEGV to GDB_SIGNAL_TRAP to be
> skipped for
> > an architecture.  The default is false (conversion enabled), preserving
> > existing behavior.
> 
> It seems gdbarch.py has been updated since the last time you generated
> gdbarch files.
> Re-generating gives the diff below.  The patch LGTM with that fixed.
> 
> Reviewed-By: Tankut Baris Aktemur <[email protected]>
> 
> Thank you.
> -Baris
> 
> 
> diff --git a/gdb/gdbarch-gen.c b/gdb/gdbarch-gen.c
> index d9bb3e7078c..0b815296261 100644
> --- a/gdb/gdbarch-gen.c
> +++ b/gdb/gdbarch-gen.c
> @@ -5295,8 +5295,8 @@ set_gdbarch_get_shadow_stack_pointer (struct
> gdbarch *gdbarch,
>  bool
>  gdbarch_imprecise_pagefault_reporting (struct gdbarch *gdbarch)
>  {
> -  gdb_assert (gdbarch != NULL);
> -  gdb_assert (gdbarch->imprecise_pagefault_reporting != NULL);
> +  gdb_assert (gdbarch != nullptr);
> +  gdb_assert (gdbarch->imprecise_pagefault_reporting != nullptr);
>    if (gdbarch_debug >= 2)
>      gdb_printf (gdb_stdlog, "gdbarch_imprecise_pagefault_reporting
> called\n");
>    return gdbarch->imprecise_pagefault_reporting ();
> diff --git a/gdb/gdbarch-gen.h b/gdb/gdbarch-gen.h
> index bb95df25eb6..a96692c206c 100644
> --- a/gdb/gdbarch-gen.h
> +++ b/gdb/gdbarch-gen.h
> @@ -1756,6 +1756,6 @@ void set_gdbarch_get_shadow_stack_pointer
> (struct gdbarch *gdbarch, gdbarch_get_
>  /* Returns true if architecture has imprecise pagefault reporting.  This is
>     used in conversion of SIGSEGV to SIGTRAP for an architecture. */
> 
> -typedef bool (gdbarch_imprecise_pagefault_reporting_ftype) ();
> -extern bool gdbarch_imprecise_pagefault_reporting (struct gdbarch
> *gdbarch);
> -extern void set_gdbarch_imprecise_pagefault_reporting (struct gdbarch
> *gdbarch, gdbarch_imprecise_pagefault_reporting_ftype
> *imprecise_pagefault_reporting);
> +using gdbarch_imprecise_pagefault_reporting_ftype = bool ();
> +bool gdbarch_imprecise_pagefault_reporting (struct gdbarch *gdbarch);
> +void set_gdbarch_imprecise_pagefault_reporting (struct gdbarch *gdbarch,
> gdbarch_imprecise_pagefault_reporting_ftype
> *imprecise_pagefault_reporting);
> 

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