From: Breno Leitao Date: Mon, 22 Dec 2025 15:28:55 +0000 (-0800) Subject: arm64: mm: warn once for ioremap attempts on RAM mappings X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=53f45f045cbe89024d2b71c145c782bb6a82a602;p=thirdparty%2Flinux.git arm64: mm: warn once for ioremap attempts on RAM mappings Replace WARN_ON with WARN_ONCE when detecting attempts to ioremap RAM. This prevents log spam when a misbehaving driver repeatedly tries to map RAM via ioremap. A single warning is more than enough to show the broken code path, and extra reports don't add extra information. Warning floods have been seen in production environments where broken external drivers hit this code path thousand of times, causing unnecessary messages to be printed and pressure on the serial console. Signed-off-by: Breno Leitao Acked-by: Catalin Marinas Signed-off-by: Will Deacon --- diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c index 10e246f112710..b12cbed9b5ad6 100644 --- a/arch/arm64/mm/ioremap.c +++ b/arch/arm64/mm/ioremap.c @@ -24,7 +24,8 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, return NULL; /* Don't allow RAM to be mapped. */ - if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr)))) + if (WARN_ONCE(pfn_is_map_memory(__phys_to_pfn(phys_addr)), + "ioremap attempted on RAM pfn\n")) return NULL; /*