commit 33fc9e26b7cb39f0d4219c875a2451802249c225
author Seth Jenkins <sethjenkins@google.com> Thu Oct 27 11:36:52 2022 -0400
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Sat Oct 29 10:12:58 2022 +0200
tree 6cecd047ea52b6e8621ec87dcad7c23471132b5d
parent b9d8cbe90a0f27f2ec4f6f32e7faf86282eb4d7d

mm: /proc/pid/smaps_rollup: fix no vma's null-deref

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/proc/task_mmu.c

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index d9c07ee..c3b7674 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -951,7 +951,7 @@
 		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");