The patch below does not apply to the 6.17-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.17.y git checkout FETCH_HEAD git cherry-pick -x f5e31a196edcd1f1bb44f26b6f9299b9a5b9b3c4 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025120121-fifteen-liver-792b@gregkh' --subject-prefix 'PATCH 6.17.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f5e31a196edcd1f1bb44f26b6f9299b9a5b9b3c4 Mon Sep 17 00:00:00 2001 From: Youngjun Park youngjun.park@lge.com Date: Sun, 2 Nov 2025 17:24:56 +0900 Subject: [PATCH] mm: swap: remove duplicate nr_swap_pages decrement in get_swap_page_of_type()
After commit 4f78252da887, nr_swap_pages is decremented in swap_range_alloc(). Since cluster_alloc_swap_entry() calls swap_range_alloc() internally, the decrement in get_swap_page_of_type() causes double-decrementing.
As a representative userspace-visible runtime example of the impact, /proc/meminfo reports increasingly inaccurate SwapFree values. The discrepancy grows with each swap allocation, and during hibernation when large amounts of memory are written to swap, the reported value can deviate significantly from actual available swap space, misleading users and monitoring tools.
Remove the duplicate decrement.
Link: https://lkml.kernel.org/r/20251102082456.79807-1-youngjun.park@lge.com Fixes: 4f78252da887 ("mm: swap: move nr_swap_pages counter decrement from folio_alloc_swap() to swap_range_alloc()") Signed-off-by: Youngjun Park youngjun.park@lge.com Acked-by: Chris Li chrisl@kernel.org Reviewed-by: Barry Song baohua@kernel.org Reviewed-by: Kairui Song kasong@tencent.com Acked-by: Nhat Pham nphamcs@gmail.com Cc: Baoquan He bhe@redhat.com Cc: Kemeng Shi shikemeng@huaweicloud.com Cc: stable@vger.kernel.org [6.17+] Signed-off-by: Andrew Morton akpm@linux-foundation.org
diff --git a/mm/swapfile.c b/mm/swapfile.c index 10760240a3a2..a1b4b9d80e3b 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2005,10 +2005,8 @@ swp_entry_t get_swap_page_of_type(int type) local_lock(&percpu_swap_cluster.lock); offset = cluster_alloc_swap_entry(si, 0, 1); local_unlock(&percpu_swap_cluster.lock); - if (offset) { + if (offset) entry = swp_entry(si->type, offset); - atomic_long_dec(&nr_swap_pages); - } } put_swap_device(si); }