On Tue, Feb 28, 2023 at 6:24 AM Dan Carpenter <error27@xxxxxxxxx> wrote: > > tree: https://github.com/ammarfaizi2/linux-block akpm/mm/mm-unstable > head: 61edd3b68c3185673c9b05dfe48038692964c73b > commit: f517f7ae341d933856cdf4d9d773027681ed5dff [82/99] mm/mmap: write-lock VMAs in vma_prepare before modifying them > config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20230228/202302281802.J93Nma7q-lkp@xxxxxxxxx/config) > compiler: gcc-11 (Debian 11.3.0-8) 11.3.0 > > If you fix the issue, kindly add following tag where applicable > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > | Reported-by: Dan Carpenter <error27@xxxxxxxxx> > | Link: https://lore.kernel.org/r/202302281802.J93Nma7q-lkp@xxxxxxxxx/ Thanks for reporting! > > smatch warnings: > mm/mmap.c:516 vma_prepare() error: we previously assumed 'vp->vma' could be null (see line 505) > > vim +516 mm/mmap.c > > 440703e082b9c7 Liam R. Howlett 2023-01-20 503 static inline void vma_prepare(struct vma_prepare *vp) > 440703e082b9c7 Liam R. Howlett 2023-01-20 504 { > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 @505 if (vp->vma) > > Check presumes that vp->vma can be NULL. On my other system (with > yesterday's linux-next code) vp->vma can never be NULL. I think the check here is not needed since vp->vma should always be non-NULL. I'll double-check and will remove it if that is confirmed. Thanks, Suren. > > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 506 vma_start_write(vp->vma); > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 507 if (vp->adj_next) > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 508 vma_start_write(vp->adj_next); > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 509 /* vp->insert is always a newly created VMA, no need for locking */ > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 510 if (vp->remove) > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 511 vma_start_write(vp->remove); > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 512 if (vp->remove2) > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 513 vma_start_write(vp->remove2); > f517f7ae341d93 Suren Baghdasaryan 2023-02-27 514 > 440703e082b9c7 Liam R. Howlett 2023-01-20 515 if (vp->file) { > 440703e082b9c7 Liam R. Howlett 2023-01-20 @516 uprobe_munmap(vp->vma, vp->vma->vm_start, vp->vma->vm_end); > ^^^^^^^ > Uncheck dereference. > > 440703e082b9c7 Liam R. Howlett 2023-01-20 517 > 440703e082b9c7 Liam R. Howlett 2023-01-20 518 if (vp->adj_next) > 440703e082b9c7 Liam R. Howlett 2023-01-20 519 uprobe_munmap(vp->adj_next, vp->adj_next->vm_start, > 440703e082b9c7 Liam R. Howlett 2023-01-20 520 vp->adj_next->vm_end); > 440703e082b9c7 Liam R. Howlett 2023-01-20 521 > 440703e082b9c7 Liam R. Howlett 2023-01-20 522 i_mmap_lock_write(vp->mapping); > 440703e082b9c7 Liam R. Howlett 2023-01-20 523 if (vp->insert && vp->insert->vm_file) { > 440703e082b9c7 Liam R. Howlett 2023-01-20 524 /* > 440703e082b9c7 Liam R. Howlett 2023-01-20 525 * Put into interval tree now, so instantiated pages > 440703e082b9c7 Liam R. Howlett 2023-01-20 526 * are visible to arm/parisc __flush_dcache_page > 440703e082b9c7 Liam R. Howlett 2023-01-20 527 * throughout; but we cannot insert into address > 440703e082b9c7 Liam R. Howlett 2023-01-20 528 * space until vma start or end is updated. > 440703e082b9c7 Liam R. Howlett 2023-01-20 529 */ > 440703e082b9c7 Liam R. Howlett 2023-01-20 530 __vma_link_file(vp->insert, > 440703e082b9c7 Liam R. Howlett 2023-01-20 531 vp->insert->vm_file->f_mapping); > 440703e082b9c7 Liam R. Howlett 2023-01-20 532 } > 440703e082b9c7 Liam R. Howlett 2023-01-20 533 } > 440703e082b9c7 Liam R. Howlett 2023-01-20 534 > 440703e082b9c7 Liam R. Howlett 2023-01-20 535 if (vp->anon_vma) { > 440703e082b9c7 Liam R. Howlett 2023-01-20 536 anon_vma_lock_write(vp->anon_vma); > 440703e082b9c7 Liam R. Howlett 2023-01-20 537 anon_vma_interval_tree_pre_update_vma(vp->vma); > > More unchecked dereferences. > > 440703e082b9c7 Liam R. Howlett 2023-01-20 538 if (vp->adj_next) > 440703e082b9c7 Liam R. Howlett 2023-01-20 539 anon_vma_interval_tree_pre_update_vma(vp->adj_next); > 440703e082b9c7 Liam R. Howlett 2023-01-20 540 } > 440703e082b9c7 Liam R. Howlett 2023-01-20 541 > 440703e082b9c7 Liam R. Howlett 2023-01-20 542 if (vp->file) { > 440703e082b9c7 Liam R. Howlett 2023-01-20 543 flush_dcache_mmap_lock(vp->mapping); > 440703e082b9c7 Liam R. Howlett 2023-01-20 544 vma_interval_tree_remove(vp->vma, &vp->mapping->i_mmap); > 440703e082b9c7 Liam R. Howlett 2023-01-20 545 if (vp->adj_next) > 440703e082b9c7 Liam R. Howlett 2023-01-20 546 vma_interval_tree_remove(vp->adj_next, > 440703e082b9c7 Liam R. Howlett 2023-01-20 547 &vp->mapping->i_mmap); > 440703e082b9c7 Liam R. Howlett 2023-01-20 548 } > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests >
