[RESEND PATCH] cxl: Fix coredump generation when cxl_get_fd() is used

[Michael Ellerman]

Frederic Barrat <fbarrat at linux.vnet.ibm.com> writes:

> If a process dumps core while owning a cxl file descriptor obtained
> from an AFU driver (e.g. cxlflash) through the cxl_get_fd() API, the
> following error occurs:
>
> [  868.027591] Unable to handle kernel paging request for data at address ...
> [  868.027778] Faulting instruction address: 0xc00000000035edb0
> cpu 0x8c: Vector: 300 (Data Access) at [c000003c688275e0]
>     pc: c00000000035edb0: elf_core_dump+0xd60/0x1300
>     lr: c00000000035ed80: elf_core_dump+0xd30/0x1300
>     sp: c000003c68827860
>    msr: 9000000100009033
>    dar: c
> dsisr: 40000000
>  current = 0xc000003c68780000
>  paca    = 0xc000000001b73200   softe: 0        irq_happened: 0x01
>     pid   = 46725, comm = hxesurelock
> enter ? for help
> [c000003c68827a60] c00000000036948c do_coredump+0xcec/0x11e0
> [c000003c68827c20] c0000000000ce9e0 get_signal+0x540/0x7b0
> [c000003c68827d10] c000000000017354 do_signal+0x54/0x2b0
> [c000003c68827e00] c00000000001777c do_notify_resume+0xbc/0xd0
> [c000003c68827e30] c000000000009838 ret_from_except_lite+0x64/0x68
> --- Exception: 300 (Data Access) at 00003fff98ad2918

Just FYI, the triple "---" is the "end of change log" marker. It took me
a while to work out why whenever I applied this I only got half the
change log and no sign offs :D

Personally I like to indent oopses anyway, which also avoids that
problem.

cheers