From 683966ac69a05c07817ed4a8f4c4c44601adc133 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Thu, 6 Jul 2023 14:51:35 -0400 Subject: [PATCH] UPSTREAM: mm/mmap: Fix extra maple tree write based on commit 0503ea8f5ba73eb3ab13a81c1eefbaf51405385a upstream. This was inadvertently fixed during the removal of __vma_adjust(). When __vma_adjust() is adjusting next with a negative value (pushing vma->vm_end lower), there would be two writes to the maple tree. The first write is unnecessary and uses all allocated nodes in the maple state. The second write is necessary but will need to allocate nodes since the first write has used the allocated nodes. This may be a problem as it may not be safe to allocate at this time, such as a low memory situation. Fix the issue by avoiding the first write and only write the adjusted "next" VMA. Reported-by: John Hsu Link: https://lore.kernel.org/lkml/9cb8c599b1d7f9c1c300d1a334d5eb70ec4d7357.camel@mediatek.com/ Cc: stable@vger.kernel.org Cc: linux-mm@kvack.org Signed-off-by: Liam R. Howlett Signed-off-by: Greg Kroah-Hartman (cherry picked from commit a02c6dc0eff249970a74c4111985b6c1fabe9851 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git linux-6.1.y) Bug: 295269894 Change-Id: I1a4bdc080d4ee92dbe06dc788961532d0c85fd7c Signed-off-by: Suren Baghdasaryan --- mm/mmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index 9a61b1ce8b76..2a8e7396413a 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -801,7 +801,8 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start, } if (end != vma->vm_end) { if (vma->vm_end > end) { - if (adjust_next >= 0 && !insert) { + if ((vma->vm_end + adjust_next != end) && + (!insert || (insert->vm_start != end))) { vma_mas_szero(&mas, end, vma->vm_end); mas_reset(&mas); VM_WARN_ON(insert &&