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author | Steve Sistare <steven.sistare@oracle.com> | 2024-09-03 16:25:21 +0200 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-26 23:01:43 +0200 |
commit | ce645b9fdc78ec5d28067286e92871ddae6817d5 (patch) | |
tree | 6138bc81e2ee99b0a471fcd9ba1c0e5e9ecab782 | |
parent | mm/gup: fix memfd_pin_folios hugetlb page allocation (diff) | |
download | linux-ce645b9fdc78ec5d28067286e92871ddae6817d5.tar.xz linux-ce645b9fdc78ec5d28067286e92871ddae6817d5.zip |
mm/gup: fix memfd_pin_folios alloc race panic
If memfd_pin_folios tries to create a hugetlb page, but someone else
already did, then folio gets the value -EEXIST here:
folio = memfd_alloc_folio(memfd, start_idx);
if (IS_ERR(folio)) {
ret = PTR_ERR(folio);
if (ret != -EEXIST)
goto err;
then on the next trip through the "while start_idx" loop we panic here:
if (folio) {
folio_put(folio);
To fix, set the folio to NULL on error.
Link: https://lkml.kernel.org/r/1725373521-451395-6-git-send-email-steven.sistare@oracle.com
Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios")
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r-- | mm/gup.c | 1 |
1 files changed, 1 insertions, 0 deletions
@@ -3702,6 +3702,7 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, ret = PTR_ERR(folio); if (ret != -EEXIST) goto err; + folio = NULL; } } } |