The patch below does not apply to the 6.1-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@xxxxxxxxxxxxxxx>. 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-6.1.y git checkout FETCH_HEAD git cherry-pick -x 6c26bd4384da24841bac4f067741bbca18b0fb74 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023072106-monologue-browsing-161a@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 6c26bd4384da ("mm/mmap: Fix error return in do_vmi_align_munmap()") 606c812eb1d5 ("mm/mmap: Fix error path in do_vmi_align_munmap()") 457f67be5910 ("mm: introduce vma detached flag") 73046fd00b06 ("mm: write-lock VMAs before removing them from VMA tree") 5e31275cc997 ("mm: add per-VMA lock and helper functions to control it") 438b6e12cd60 ("mm: move mmap_lock assert function definitions") 440703e082b9 ("mm/mmap: refactor locking out of __vma_adjust()") e3d73f848e5f ("mm/mmap: move anon_vma setting in __vma_adjust()") 9e56044625a1 ("mm: pass through vma iterator to __vma_adjust()") fbcc3104b843 ("mmap: convert __vma_adjust() to use vma iterator") 183654ce26a5 ("mmap: change do_mas_munmap and do_mas_aligned_munmap() to use vma iterator") 0378c0a0e9e4 ("mm/mmap: remove preallocation from do_mas_align_munmap()") 92fed82047d7 ("mm/mmap: convert brk to use vma iterator") b62b633e048b ("mm: expand vma iterator interface") baabcfc93d3b ("mm/mmap: fix typo in comment") c5d5546ea065 ("maple_tree: remove the parameter entry of mas_preallocate") 675eaca1f441 ("mm/mmap: properly unaccount memory on mas_preallocate() failure") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 6c26bd4384da24841bac4f067741bbca18b0fb74 Mon Sep 17 00:00:00 2001 From: David Woodhouse <dwmw@xxxxxxxxxxxx> 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 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 <dwmw@xxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> diff --git a/mm/mmap.c b/mm/mmap.c index d600404580b2..13128e908470 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2387,7 +2387,8 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, } vma_start_write(next); 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; vma_mark_detached(next, true); if (next->vm_flags & VM_LOCKED) @@ -2436,12 +2437,12 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, BUG_ON(count != test_count); } #endif - /* Point of no return */ - error = -ENOMEM; vma_iter_set(vmi, start); - if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL)) + error = vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL); + if (error) goto clear_tree_failed; + /* Point of no return */ mm->locked_vm -= locked_vm; mm->map_count -= count; /*
