This is a note to let you know that I've just added the patch titled
mm, mremap: fix mremap() expanding vma with addr inside vma
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-mremap-fix-mremap-expanding-vma-with-addr-inside-vma.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6f12be792fde994ed934168f93c2a0d2a0cf0bc5 Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@xxxxxxx>
Date: Fri, 16 Dec 2022 17:32:27 +0100
Subject: mm, mremap: fix mremap() expanding vma with addr inside vma
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From: Vlastimil Babka <vbabka@xxxxxxx>
commit 6f12be792fde994ed934168f93c2a0d2a0cf0bc5 upstream.
Since 6.1 we have noticed random rpm install failures that were tracked to
mremap() returning -ENOMEM and to commit ca3d76b0aa80 ("mm: add merging
after mremap resize").
The problem occurs when mremap() expands a VMA in place, but using an
starting address that's not vma->vm_start, but somewhere in the middle.
The extension_pgoff calculation introduced by the commit is wrong in that
case, so vma_merge() fails due to pgoffs not being compatible. Fix the
calculation.
By the way it seems that the situations, where rpm now expands a vma from
the middle, were made possible also due to that commit, thanks to the
improved vma merging. Yet it should work just fine, except for the buggy
calculation.
Link: https://lkml.kernel.org/r/20221216163227.24648-1-vbabka@xxxxxxx
Reported-by: Jiri Slaby <jirislaby@xxxxxxxxxx>
Link: https://bugzilla.suse.com/show_bug.cgi?id=1206359
Fixes: ca3d76b0aa80 ("mm: add merging after mremap resize")
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Jakub Matěna <matenajakub@xxxxxxxxx>
Cc: "Kirill A . Shutemov" <kirill@xxxxxxxxxxxxx>
Cc: Liam Howlett <liam.howlett@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1016,7 +1016,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, a
long pages = (new_len - old_len) >> PAGE_SHIFT;
unsigned long extension_start = addr + old_len;
unsigned long extension_end = addr + new_len;
- pgoff_t extension_pgoff = vma->vm_pgoff + (old_len >> PAGE_SHIFT);
+ pgoff_t extension_pgoff = vma->vm_pgoff +
+ ((extension_start - vma->vm_start) >> PAGE_SHIFT);
if (vma->vm_flags & VM_ACCOUNT) {
if (security_vm_enough_memory_mm(mm, pages)) {
Patches currently in stable-queue which might be from vbabka@xxxxxxx are
queue-6.1/mm-mremap-fix-mremap-expanding-vma-with-addr-inside-vma.patch
queue-6.1/mm-mempolicy-fix-memory-leak-in-set_mempolicy_home_node-system-call.patch
