From: Lance Yang lance.yang@linux.dev
The error path in secretmem_fault() frees a folio before restoring its direct map status, which is a race leading to a panic.
Fix the ordering to restore the map before the folio is freed.
Cc: stable@vger.kernel.org Reported-by: Google Big Sleep big-sleep-vuln-reports@google.com Closes: https://lore.kernel.org/linux-mm/CAEXGt5QeDpiHTu3K9tvjUTPqo+d-=wuCNYPa+6sWKr... Signed-off-by: Lance Yang lance.yang@linux.dev --- mm/secretmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/secretmem.c b/mm/secretmem.c index c1bd9a4b663d..37f6d1097853 100644 --- a/mm/secretmem.c +++ b/mm/secretmem.c @@ -82,13 +82,13 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf) __folio_mark_uptodate(folio); err = filemap_add_folio(mapping, folio, offset, gfp); if (unlikely(err)) { - folio_put(folio); /* * If a split of large page was required, it * already happened when we marked the page invalid * which guarantees that this call won't fail */ set_direct_map_default_noflush(folio_page(folio, 0)); + folio_put(folio); if (err == -EEXIST) goto retry;