From 42a018a796d1eedb0d7c38b2778ef3dbf05aca36 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Wed, 28 Jun 2023 10:55:03 +0100 Subject: [PATCH] mm/mmap: Fix error return in do_vmi_align_munmap() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 6c26bd4384da24841bac4f067741bbca18b0fb74 upstream, If mas_store_gfp() in the gather loop failed, the 'error' variable that ultimately gets returned was not being set. In many cases, its original value of -ENOMEM was still in place, and that was fine. But if VMAs had been split at the start or end of the range, then 'error' could be zero. Change to the 'error = foo(); if (error) goto …' idiom to fix the bug. Also clean up a later case which avoided the same bug by *explicitly* setting error = -ENOMEM right before calling the function that might return -ENOMEM. In a final cosmetic change, move the 'Point of no return' comment to *after* the goto. That's been in the wrong place since the preallocation was removed, and this new error path was added. Fixes: 606c812eb1d5 ("mm/mmap: Fix error path in do_vmi_align_munmap()") Signed-off-by: David Woodhouse Cc: stable@vger.kernel.org Reviewed-by: Greg Kroah-Hartman Reviewed-by: Liam R. Howlett Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- mm/mmap.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index d82a95956defd..f031fa267913d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2404,7 +2404,8 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma, break; } mas_set_range(&mas_detach, next->vm_start, next->vm_end - 1); - if (mas_store_gfp(&mas_detach, next, GFP_KERNEL)) + error = mas_store_gfp(&mas_detach, next, GFP_KERNEL); + if (error) goto munmap_gather_failed; if (next->vm_flags & VM_LOCKED) locked_vm += vma_pages(next); @@ -2456,6 +2457,7 @@ do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma, mas_set_range(mas, start, end - 1); } #endif + /* Point of no return */ mas_store_prealloc(mas, NULL); mm->locked_vm -= locked_vm;