CVE-2026-31654

Description

In the Linux kernel, the following vulnerability has been resolved: mm/vma: fix memory leak in __mmap_region() commit 605f6586ecf7 (-mm/vma: do not leak memory when .mmap_prepare swaps the file-) handled the success path by skipping get_file() via file_doesnt_need_get, but missed the error path. When /dev/zero is mmap-d with MAP_SHARED, mmap_zero_prepare() calls shmem_zero_setup_desc() which allocates a new shmem file to back the mapping. If __mmap_new_vma() subsequently fails, this replacement file is never fput()-d - the original is released by ksys_mmap_pgoff(), but nobody releases the new one. Add fput() for the swapped file in the error path. Reproducible with fault injection. FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 2 UID: 0 PID: 366 Comm: syz.7.14 Not tainted 7.0.0-rc6 #2 PREEMPT(full) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> du...