[Crash-utility] [PATCH RESEND v2] diskdump: add hook for additional checks on prstatus notes validity

[HAGIO KAZUHITO(萩尾 一仁)]

On 2023/10/14 22:39, Aditya Gupta wrote:
> Upstream crash reports these warnings on PowerPC64:
> 
>      WARNING: cpu 0 invalid NT_PRSTATUS note (n_type != NT_PRSTATUS)
>      ...
> 
> Apart from these warnings, register values are also invalid.
> 
> This warning was found in the commit:
> 
>      commit db8c030857b4 ("diskdump/netdump: fix segmentation fault
>      caused by failure of stopping CPUs")
> 
> With above commit, crash checks whether 'crash_notes' is initialised,
> before mapping PRSTATUS notes.
> 
> But some architectures such as PowerPC64, in fadump case
> (firmware-assisted dump), don't populate 'crash_notes' since the
> registers are already stored in the cpu notes in the vmcore.
> 
> Instead of checking 'crash_notes' for all architectures, introduce
> a machdep hook ('is_cpu_prstatus_valid'), for architectures to
> decide validity checks for PRSTATUS notes
> 
> A default hook ('diskdump_is_cpu_prstatus_valid') has also been provided
> for all architectures other than PowerPC64, which checks if 'crash_notes'
> for a given cpu is valid, maintaining the current behaviour
> 
> PowerPC64 doesn't utilise 'crash_notes' to get register values, so no
> additional checks are required
> 
> Fixes: db8c030857b4 ("diskdump/netdump: fix segmentation fault caused by failure of stopping CPUs")
> Signed-off-by: Aditya Gupta <adityag at linux.ibm.com>

Thanks, looks good and applied.

https://github.com/crash-utility/crash/commit/ac097d6cb15726fa34f2d4ec5edc94aad58e0d0d

Thanks,
Kazu