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

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(a)linux.ibm.com&gt;