Re: reliable reproducer, was Re: core dump analysis

Hi Andreas,

Am 22.04.2023 um 20:07 schrieb Andreas Schwab:
> On Apr 22 2023, Michael Schmitz wrote:
>
>> Took a little while to figure out that the ucontext format changed in the
>> decade or two since my userland's libc headers were generated.
>
> In which way did it change?

This is the definition from the kernel's 
include/uapi/asm-generic/ucontext.h:

struct ucontext {
         unsigned long     uc_flags;
         struct ucontext  *uc_link;
         stack_t           uc_stack;
         struct sigcontext uc_mcontext;
         sigset_t          uc_sigmask;   /* mask last for extensibility */
};

And this is /usr/include/sys/ucontext.h:

/* Userlevel context.  */
typedef struct ucontext
{
   unsigned long int uc_flags;
   struct ucontext *uc_link;
   __sigset_t uc_sigmask;
   stack_t uc_stack;
   mcontext_t uc_mcontext;
   long int uc_filler[174];
} ucontext_t;

uc_sigmask appears before uc_stack and uc_mcontext.

I'm assuming libc just passes on what the kernel set, without reordering?

Cheers,

	Michael