Messages in this thread Patch in this message |  | | From | Jim Cromie <> | Subject | [RFC PATCH v6 27/34] dyndbg: fixup protect header when deleting site | Date | Sat, 29 May 2021 14:00:22 -0600 |
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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 659e864837ad..f2f6f2b20d01 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
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