Re: [PATCH v1 2/4] powerpc/mm: print warning in arch_remove_linear_mapping()
From: David Hildenbrand
Date: Wed Nov 11 2020 - 07:18:56 EST
On 04.11.20 10:42, osalvador wrote:
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).
Exactly.
But anyway, being coherent with that, I think you should remove the WARN_ON
in hash__remove_section_mapping as well.
Thanks, I'll add a patch doing that.
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.
Right. Thanks!
--
Thanks,
David / dhildenb