diff options
| author | Ye Liu <liuye@kylinos.cn> | 2026-08-06 08:45:55 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-08-24 18:43:08 -0700 |
| commit | 54cc9b38470905e7fdf4a8786e9b1b85ac045f0a (patch) | |
| tree | 874eba66fbe109e4e8feec54f20867c82e15c6ac | |
| parent | 4b82a0b91be5f8cf7a3a46d6fa3931224150b6b4 (diff) | |
mm: debug_page_alloc: fix NULL buf in debug_guardpage_minorder_setup
If the kernel command line includes "debug_guardpage_minorder" without an
equals sign (i.e., no value is provided), the early parameter parser
passes a NULL buf pointer to the setup function.
kstrtouint() does not perform a NULL check on its input and calls directly
into kstrtoull() which dereferences s[0] unconditionally, leading to a
NULL pointer dereference and early boot crash.
Additionally, the error path's pr_err("%s", buf) would also crash with a
NULL format argument.
Link: https://lore.kernel.org/20260806004556.2633049-1-ye.liu@linux.dev
Fixes: c0a32fc5a2e4 ("mm: more intensive memory corruption debugging")
Signed-off-by: Ye Liu <liuye@kylinos.cn>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/debug_page_alloc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/debug_page_alloc.c b/mm/debug_page_alloc.c index 41e3d1f1ad96..fd2664c3c86a 100644 --- a/mm/debug_page_alloc.c +++ b/mm/debug_page_alloc.c @@ -22,8 +22,8 @@ static int __init debug_guardpage_minorder_setup(char *buf) { unsigned int res; - if (kstrtouint(buf, 10, &res) < 0 || res > MAX_PAGE_ORDER / 2) { - pr_err("Bad debug_guardpage_minorder value: %s\n", buf); + if (!buf || kstrtouint(buf, 10, &res) < 0 || res > MAX_PAGE_ORDER / 2) { + pr_err("Bad debug_guardpage_minorder value: %s\n", buf ?: "(missing)"); return 0; } _debug_guardpage_minorder = res; |