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") Signed-off-by: Seth Jenkins sethjenkins@google.com Reviewed-by: Alexey Dobriyan adobriyan@gmail.com Tested-by: Alexey Dobriyan adobriyan@gmail.com --- c4c84f06285e on upstream resolves this issue as part of the switch to using maple trees for VMA lookups, but a fix must still be applied to stable trees 4.19-5.19.

fs/proc/task_mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 4e0023643f8b..1e7bbc0873a4 100644 --- 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");