From: osalvador <osalvador@suse.de>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@lists.ozlabs.org,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Rashmica Gupta <rashmica.g@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Rapoport <rppt@kernel.org>, Michal Hocko <mhocko@suse.com>,
Wei Yang <richard.weiyang@linux.alibaba.com>
Subject: Re: [PATCH v1 2/4] powerpc/mm: print warning in arch_remove_linear_mapping()
Date: Wed, 4 Nov 2020 10:42:55 +0100 [thread overview]
Message-ID: <20201104094255.GA4981@localhost.localdomain> (raw)
In-Reply-To: <20201029162718.29910-3-david@redhat.com>
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@ellerman.id.au>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Rashmica Gupta <rashmica.g@gmail.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Mike Rapoport <rppt@kernel.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> 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
next prev parent reply other threads:[~2020-11-04 9:43 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-29 16:27 [PATCH v1 0/4] powernv/memtrace: don't abuse memory hot(un)plug infrastructure for memory allocations David Hildenbrand
2020-10-29 16:27 ` [PATCH v1 1/4] powerpc/mm: factor out creating/removing linear mapping David Hildenbrand
2020-10-29 16:27 ` [PATCH v1 2/4] powerpc/mm: print warning in arch_remove_linear_mapping() David Hildenbrand
2020-11-04 9:42 ` osalvador [this message]
2020-11-11 12:10 ` David Hildenbrand
2020-10-29 16:27 ` [PATCH v1 3/4] powerpc/mm: remove linear mapping if __add_pages() fails in arch_add_memory() David Hildenbrand
2020-11-04 9:50 ` osalvador
2020-11-04 12:06 ` Mike Rapoport
2020-11-04 12:11 ` Oscar Salvador
2020-11-11 12:07 ` David Hildenbrand
2020-11-04 12:11 ` Oscar Salvador
2020-10-29 16:27 ` [PATCH v1 4/4] powernv/memtrace: don't abuse memory hot(un)plug infrastructure for memory allocations David Hildenbrand
2020-11-03 9:23 ` Michal Hocko
2020-11-03 9:29 ` David Hildenbrand
2020-11-05 2:40 ` Michael Ellerman
2020-11-05 8:29 ` David Hildenbrand
2020-11-05 10:47 ` Michael Ellerman
2020-11-25 11:57 ` [PATCH v1 0/4] " Michael Ellerman
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