From f9dc428249ed962a70acf301f01eae8578449161 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Tue, 18 Aug 2026 02:03:40 -0700 Subject: [PATCH] mm, swap: ratelimit bad swap entry reports A corrupt page table hands the same bogus entry to get_swap_device() on every access to the mapping, and every rejection is logged. One machine logged 6185620 copies of the same line in a few hours. swap_dup_entry_direct() prints the same message from the fork path, once per call: the WARN_ON_ONCE() guarding it warns once, the pr_err() inside does not. Rate limit all three prints. Link: https://lore.kernel.org/20260818-swap_part_one-v1-1-a4fc58119fc0@debian.org Fixes: 23b230ba8ac3 ("mm/swap: print bad swap offset entry in get_swap_device") Signed-off-by: Breno Leitao Reviewed-by: Barry Song Reviewed-by: Nhat Pham Acked-by: Kairui Song Acked-by: David Hildenbrand (Arm) Cc: Baoquan He Cc: Chris Li Cc: Kemeng Shi Cc: Miaohe Lin Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton --- mm/swapfile.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index dacef34a3ed7..53bf01d5f7f1 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1899,11 +1899,11 @@ struct swap_info_struct *get_swap_device(swp_entry_t entry) return si; bad_nofile: - pr_err("%s: %s%08lx\n", __func__, Bad_file, entry.val); + pr_err_ratelimited("%s: %s%08lx\n", __func__, Bad_file, entry.val); out: return NULL; put_out: - pr_err("%s: %s%08lx\n", __func__, Bad_offset, entry.val); + pr_err_ratelimited("%s: %s%08lx\n", __func__, Bad_offset, entry.val); percpu_ref_put(&si->users); return NULL; } @@ -3883,7 +3883,7 @@ int swap_dup_entry_direct(swp_entry_t entry) si = swap_entry_to_info(entry); if (WARN_ON_ONCE(!si)) { - pr_err("%s%08lx\n", Bad_file, entry.val); + pr_err_ratelimited("%s%08lx\n", Bad_file, entry.val); return -EINVAL; }