Several architectures has done checking if slab if available in ioremap_prot(). In fact it should be done in generic ioremap_prot() since on any architecutre, slab allocator must be available before get_vm_area_caller() and vunmap() are used. Add the checking into generic_ioremap_prot(). Suggested-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> Reviewed-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx> --- v5-v6: Add WARN_ON_ONCE to aid debugging - Christoph. mm/ioremap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/ioremap.c b/mm/ioremap.c index 9f34a8f90b58..86b82ec27d2b 100644 --- a/mm/ioremap.c +++ b/mm/ioremap.c @@ -18,6 +18,10 @@ void __iomem *generic_ioremap_prot(phys_addr_t phys_addr, size_t size, phys_addr_t last_addr; struct vm_struct *area; + /* An early platform driver might end up here */ + if (WARN_ON_ONCE(!slab_is_available())) + return NULL; + /* Disallow wrap-around or zero size */ last_addr = phys_addr + size - 1; if (!size || last_addr < phys_addr) -- 2.34.1
