All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jim Cromie <jim.cromie@gmail.com>
To: jbaron@akamai.com, gregkh@linuxfoundation.org,
	linux-kernel@vger.kernel.org
Cc: Jim Cromie <jim.cromie@gmail.com>
Subject: [RFC PATCH v6 27/34] dyndbg: fixup protect header when deleting site
Date: Sat, 29 May 2021 14:00:22 -0600	[thread overview]
Message-ID: <20210529200029.205306-28-jim.cromie@gmail.com> (raw)
In-Reply-To: <20210529200029.205306-1-jim.cromie@gmail.com>

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


  parent reply	other threads:[~2021-05-29 20:03 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-29 19:59 [RFC PATCH v6 00/34] DYNAMIC_DEBUG diet progress, dropped 30kb Jim Cromie
2021-05-29 19:59 ` [RFC PATCH v6 01/34] dyndbg: avoid calling dyndbg_emit_prefix when it has no work Jim Cromie
2021-05-29 19:59 ` [RFC PATCH v6 02/34] dyndbg: drop uninformative vpr_info Jim Cromie
2021-05-29 19:59 ` [RFC PATCH v6 03/34] dyndbg: display KiB of data memory used Jim Cromie
2021-05-29 19:59 ` [RFC PATCH v6 04/34] dyndbg: split struct _ddebug's display fields to new _ddebug_site Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 05/34] dyndbg: __init iterate over __dyndbg & __dyndbg_site in parallel Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 06/34] dyndbg+module: expose ddebug_sites to modules Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 07/34] dyndbg: refactor part of ddebug_change to ddebug_match_site Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 08/34] dyndbg: accept null site in ddebug_match_site Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 09/34] dyndbg: hoist ->site out of ddebug_match_site Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 10/34] dyndbg: accept null site in ddebug_change Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 11/34] dyndbg: accept null site in dynamic_emit_prefix Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 12/34] dyndbg: accept null site in ddebug_proc_show Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 13/34] dyndbg: refactor ddebug_alter_site out of ddebug_change Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 14/34] dyndbg: allow deleting site info via control interface Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 15/34] dyndbg: add ddebug_site(_get|_put) abstraction Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 16/34] dyndbg: ddebug_add_module avoid adding empty modules Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 17/34] dyndbg: add _index to struct _ddebug Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 18/34] dyndbg: prevent build bugs via -DNO_DYNAMIC_DEBUG_TABLE Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 19/34] dyndbg: RFC - DEFINE_DYNAMIC_DEBUG_TABLE Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 20/34] dyndbg: RFC handle __dyndbg* sections in module.lds.h Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 21/34] dyndbg: ddebug_add_module() handle headers Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 22/34] dyndbg: validate ddebug_site_get invariants Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 23/34] dyndbg: fix NULL deref after deleting sites Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 24/34] dyndbg: dont show header records in control Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 25/34] dyndbg: make site pointer and checks on it optional (almost) Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 26/34] dyndbg: swap WARN_ON for BUG_ON see what 0-day says Jim Cromie
2021-05-29 20:00 ` Jim Cromie [this message]
2021-05-29 20:00 ` [RFC PATCH v6 28/34] dyndbg: unionize _ddebug*_headers with struct _ddebug* Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 29/34] dyndbg: RFC drop _ddebug.site pointer Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 30/34] dyndbg: split/copy ._index into 2 new fields: ._back, ._map Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 31/34] dyndbg: detect repeated site recs in add_module Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 32/34] dyndbg: pack module pr_debug sites Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 33/34] dyndbg: pack pr-debug site-recs in builtin modules Jim Cromie
2021-05-29 20:00 ` [RFC PATCH v6 34/34] dyndbg: prototype print-once and print-ratelimited RFC Jim Cromie

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210529200029.205306-28-jim.cromie@gmail.com \
    --to=jim.cromie@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jbaron@akamai.com \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.