60 lines
2.5 KiB
Diff
60 lines
2.5 KiB
Diff
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Vlastimil Babka <vbabka@suse.cz>
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Date: Fri, 16 Dec 2022 17:32:27 +0100
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Subject: [PATCH] mm, mremap: fix mremap() expanding vma with addr inside vma
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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commit 6f12be792fde994ed934168f93c2a0d2a0cf0bc5 upstream.
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Since 6.1 we have noticed random rpm install failures that were tracked to
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mremap() returning -ENOMEM and to commit ca3d76b0aa80 ("mm: add merging
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after mremap resize").
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The problem occurs when mremap() expands a VMA in place, but using an
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starting address that's not vma->vm_start, but somewhere in the middle.
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The extension_pgoff calculation introduced by the commit is wrong in that
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case, so vma_merge() fails due to pgoffs not being compatible. Fix the
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calculation.
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By the way it seems that the situations, where rpm now expands a vma from
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the middle, were made possible also due to that commit, thanks to the
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improved vma merging. Yet it should work just fine, except for the buggy
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calculation.
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Link: https://lkml.kernel.org/r/20221216163227.24648-1-vbabka@suse.cz
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Reported-by: Jiri Slaby <jirislaby@kernel.org>
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Link: https://bugzilla.suse.com/show_bug.cgi?id=1206359
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Fixes: ca3d76b0aa80 ("mm: add merging after mremap resize")
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Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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Cc: Jakub Matěna <matenajakub@gmail.com>
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Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
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Cc: Liam Howlett <liam.howlett@oracle.com>
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Cc: Matthew Wilcox <willy@infradead.org>
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Cc: Mel Gorman <mgorman@techsingularity.net>
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Cc: Michal Hocko <mhocko@kernel.org>
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Cc: <stable@vger.kernel.org>
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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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(cherry picked from commit 4d528dab403ba45db24769f5e5a9514ab0890351)
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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mm/mremap.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/mm/mremap.c b/mm/mremap.c
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index e465ffe279bb..fe587c5d6591 100644
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--- a/mm/mremap.c
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+++ b/mm/mremap.c
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@@ -1016,7 +1016,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
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long pages = (new_len - old_len) >> PAGE_SHIFT;
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unsigned long extension_start = addr + old_len;
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unsigned long extension_end = addr + new_len;
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- pgoff_t extension_pgoff = vma->vm_pgoff + (old_len >> PAGE_SHIFT);
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+ pgoff_t extension_pgoff = vma->vm_pgoff +
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+ ((extension_start - vma->vm_start) >> PAGE_SHIFT);
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if (vma->vm_flags & VM_ACCOUNT) {
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if (security_vm_enough_memory_mm(mm, pages)) {
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