From: Todd Kjos tkjos@android.com
This reverts commit 6bf7d3c5c0c5dad650bfc4345ed553c18b69d59e.
The commit message is for a different patch. Reverting and then adding the same patch back with the correct commit message.
Reported-by: Ben Hutchings ben.hutchings@codethink.co.uk Cc: stable stable@vger.kernel.org # 4.19 Signed-off-by: Todd Kjos tkjos@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/android/binder_alloc.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
--- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -958,13 +958,14 @@ enum lru_status binder_alloc_free_page(s
index = page - alloc->pages; page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE; - - mm = alloc->vma_vm_mm; - if (!mmget_not_zero(mm)) - goto err_mmget; - if (!down_write_trylock(&mm->mmap_sem)) - goto err_down_write_mmap_sem_failed; vma = binder_alloc_get_vma(alloc); + if (vma) { + if (!mmget_not_zero(alloc->vma_vm_mm)) + goto err_mmget; + mm = alloc->vma_vm_mm; + if (!down_write_trylock(&mm->mmap_sem)) + goto err_down_write_mmap_sem_failed; + }
list_lru_isolate(lru, item); spin_unlock(lock); @@ -977,9 +978,10 @@ enum lru_status binder_alloc_free_page(s PAGE_SIZE);
trace_binder_unmap_user_end(alloc, index); + + up_write(&mm->mmap_sem); + mmput(mm); } - up_write(&mm->mmap_sem); - mmput(mm);
trace_binder_unmap_kernel_start(alloc, index);