[RFC PATCH v5 26/28] dyndbg: fixup protect header when deleting site
From: Jim Cromie <jim.cromie@gmail.com>
Date: 2021-05-11 18:52:46
Also in:
lkml
Subsystem:
dynamic debug, library code, the rest · Maintainers:
Jason Baron, Jim Cromie, Andrew Morton, Linus Torvalds
fix a null-ptr-deref when .site info is deleted. #> echo +D > /proc/dynamic_debug/control This protects the header.site pointer from zeroing; we need it for all the SITE_CHK sanity checking. Probably should protect against toggling the static_key too (in the same function), but this smaller change fixes the crash. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- lib/dynamic_debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b61e4a211819..aa4a476d70ad 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c@@ -247,7 +247,7 @@ static void ddebug_alter_site(struct _ddebug *dp, #ifdef SITE_CHK /* delete site info for this callsite */ if (modifiers->flags & _DPRINTK_FLAGS_DELETE_SITE) { - if (dp->site) { + if (dp->site && !is_dyndbg_header_pair(dp, dp->site)) { vpr_info("dropping site info %s.%s.%d\n", dp->site->filename, dp->site->function, dp->lineno); dp->site = NULL;
--
2.31.1