Re: [PATCH] mm: /proc/pid/smaps_rollup: fix no vma's null-deref

On Mon, Oct 03, 2022 at 06:45:31PM -0400, FirstName LastName wrote:

From: Seth Jenkins sethjenkins@google.com

Commit 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value seq_file") introduced a null-deref if there are no vma's in the task in show_smaps_rollup.

Fixes: 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value seq_file") Cc: stable@vger.kernel.org Signed-off-by: Seth Jenkins sethjenkins@google.com

--- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -969,7 +969,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v) vma = vma->vm_next; }

• show_vma_header_prefix(m, priv->mm->mmap->vm_start,

• show_vma_header_prefix(m, priv->mm->mmap ? priv->mm->mmap->vm_start : 0, last_vma_end, 0, 0, 0, 0); seq_pad(m, ' '); seq_puts(m, "[rollup]\n");

Reviewed-by: Alexey Dobriyan adobriyan@gmail.com Tested-by: Alexey Dobriyan adobriyan@gmail.com

Now I know how to create stable process without address space.