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authorVlastimil Babka <vbabka@suse.cz>2022-12-16 19:32:27 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-12-22 01:31:51 +0300
commit6f12be792fde994ed934168f93c2a0d2a0cf0bc5 (patch)
treef316d96e3d8f984321769fe6cf24e08f29c2c4b7 /mm
parent1644d755d0b06d0f1ee93e1c44336c29386546b4 (diff)
downloadlinux-6f12be792fde994ed934168f93c2a0d2a0cf0bc5.tar.xz
mm, mremap: fix mremap() expanding vma with addr inside vma
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@suse.cz Reported-by: Jiri Slaby <jirislaby@kernel.org> Link: https://bugzilla.suse.com/show_bug.cgi?id=1206359 Fixes: ca3d76b0aa80 ("mm: add merging after mremap resize") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jakub Matěna <matenajakub@gmail.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mremap.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index e465ffe279bb..fe587c5d6591 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1016,7 +1016,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
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)) {