diff options
| author | Liam Howlett <liam.howlett@oracle.com> | 2022-08-10 16:02:25 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-18 16:31:02 +0200 |
| commit | d6f35446d0769a98e9d761593d267cdd24f09ecd (patch) | |
| tree | bd7a0bd371d9087d9022bb7fa7af255f8d9ba21c /drivers/android | |
| parent | a0e44c64b6061dda7e00b7c458e4523e2331b739 (diff) | |
binder_alloc: Add missing mmap_lock calls when using the VMA
Take the mmap_read_lock() when using the VMA in
binder_alloc_print_pages() and when checking for a VMA in
binder_alloc_new_buf_locked().
It is worth noting binder_alloc_new_buf_locked() drops the VMA read lock
after it verifies a VMA exists, but may be taken again deeper in the
call stack, if necessary.
Fixes: a43cfc87caaf (android: binder: stop saving a pointer to the VMA)
Cc: stable <stable@kernel.org>
Reported-by: Ondrej Mosnacek <omosnace@redhat.com>
Reported-by: syzbot+a7b60a176ec13cafb793@syzkaller.appspotmail.com
Tested-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Link: https://lore.kernel.org/r/20220810160209.1630707-1-Liam.Howlett@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/android')
| -rw-r--r-- | drivers/android/binder_alloc.c | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 1014beb12802..51f4e1c5cd01 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -402,12 +402,15 @@ static struct binder_buffer *binder_alloc_new_buf_locked( size_t size, data_offsets_size; int ret; + mmap_read_lock(alloc->vma_vm_mm); if (!binder_alloc_get_vma(alloc)) { + mmap_read_unlock(alloc->vma_vm_mm); binder_alloc_debug(BINDER_DEBUG_USER_ERROR, "%d: binder_alloc_buf, no vma\n", alloc->pid); return ERR_PTR(-ESRCH); } + mmap_read_unlock(alloc->vma_vm_mm); data_offsets_size = ALIGN(data_size, sizeof(void *)) + ALIGN(offsets_size, sizeof(void *)); @@ -929,17 +932,25 @@ void binder_alloc_print_pages(struct seq_file *m, * Make sure the binder_alloc is fully initialized, otherwise we might * read inconsistent state. */ - if (binder_alloc_get_vma(alloc) != NULL) { - for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { - page = &alloc->pages[i]; - if (!page->page_ptr) - free++; - else if (list_empty(&page->lru)) - active++; - else - lru++; - } + + mmap_read_lock(alloc->vma_vm_mm); + if (binder_alloc_get_vma(alloc) == NULL) { + mmap_read_unlock(alloc->vma_vm_mm); + goto uninitialized; } + + mmap_read_unlock(alloc->vma_vm_mm); + for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { + page = &alloc->pages[i]; + if (!page->page_ptr) + free++; + else if (list_empty(&page->lru)) + active++; + else + lru++; + } + +uninitialized: mutex_unlock(&alloc->mutex); seq_printf(m, " pages: %d:%d:%d\n", active, lru, free); seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high); |