On Thu, Oct 29, 2020 at 05:27:16PM +0100, David Hildenbrand wrote:
> Let's print a warning similar to in arch_add_linear_mapping() instead of
> WARN_ON_ONCE() and eventually crashing the kernel.
>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Rashmica Gupta <rashmica.g@xxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Mike Rapoport <rppt@xxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Oscar Salvador <osalvador@xxxxxxx>
> Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> ---
> arch/powerpc/mm/mem.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index 8a86d81f8df0..685028451dd2 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -145,7 +145,9 @@ void __ref arch_remove_linear_mapping(u64 start, u64 size)
> flush_dcache_range_chunked(start, start + size, FLUSH_CHUNK_SIZE);
>
> ret = remove_section_mapping(start, start + size);
> - WARN_ON_ONCE(ret);
> + if (ret)
> + pr_warn("Unable to remove linear mapping for 0x%llx..0x%llx: %d\n",
> + start, start + size, ret);
I guess the fear is to panic on systems that do have panic_on_warn (not
sure how many productions systems have this out there).
But anyway, being coherent with that, I think you should remove the WARN_ON
in hash__remove_section_mapping as well.
Besides that:
Reviewed-by: Oscar Salvador <osalvador@suse.
Not sure if the functions below that also have any sort of WARN_ON.
native_hpte_removebolted has a VM_WARN_ON, but that is on
CONFIG_DEBUG_VM so does not really matter.
--
Oscar Salvador
SUSE L3
