From: Seth Jenkins <sethjenkins@google.com> stable inclusion from stable-v4.19.264 commit dbe863bce7679c7f5ec0e993d834fe16c5e687b5 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I63UEU CVE: NA -------------------------------- 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> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- 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 78ce353d0dfa..cfe2c4e32533 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -851,7 +851,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v) last_vma_end = vma->vm_end; } - 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"); -- 2.25.1