From 2ccd48ce35e87f09472b42dda96fbf7b5165f3c3 Mon Sep 17 00:00:00 2001 From: Yosry Ahmed Date: Mon, 11 Mar 2024 19:43:46 +0000 Subject: [PATCH] percpu: clean up all mappings when pcpu_map_pages() fails In pcpu_map_pages(), if __pcpu_map_pages() fails on a CPU, we call __pcpu_unmap_pages() to clean up mappings on all CPUs where mappings were created, but not on the CPU where __pcpu_map_pages() fails. __pcpu_map_pages() and __pcpu_unmap_pages() are wrappers around vmap_pages_range_noflush() and vunmap_range_noflush(). All other callers of vmap_pages_range_noflush() call vunmap_range_noflush() when mapping fails, except pcpu_map_pages(). The reason could be that partial mappings may be left behind from a failed mapping attempt. Call __pcpu_unmap_pages() for the failed CPU as well in pcpu_map_pages(). This was found by code inspection, no failures or bugs were observed. Link: https://lkml.kernel.org/r/20240311194346.2291333-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed Acked-by: Dennis Zhou Cc: Christoph Lameter (Ampere) Cc: Tejun Heo Signed-off-by: Andrew Morton --- mm/percpu-vm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c index 2054c9213c43..cd69caf6aa8d 100644 --- a/mm/percpu-vm.c +++ b/mm/percpu-vm.c @@ -231,10 +231,10 @@ static int pcpu_map_pages(struct pcpu_chunk *chunk, return 0; err: for_each_possible_cpu(tcpu) { - if (tcpu == cpu) - break; __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start), page_end - page_start); + if (tcpu == cpu) + break; } pcpu_post_unmap_tlb_flush(chunk, page_start, page_end); return err;