From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 46C801773D for ; Wed, 9 Aug 2023 11:19:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE0E8C433C8; Wed, 9 Aug 2023 11:19:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691579999; bh=gedNbu5Fo2qv7/gxRsyidpC0NOd2iWfkpR/WxYHuAJI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tTbsRK3UQ0TSaLyMmP5gsewlYx9LxLXfQPPQCxoBY5brr8GY9z5koShpdGTDXQIrK oY473ID1N0w4/HHX0vMaU3KTlQoPYnR+AsSCaZ/cyqoLBxcfl/uLYTZsOqNfW9XCFx IEBlILzJkA0aUkURSumG7M3tPJXy61FGCQfQJS+E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot , Thomas Gleixner , Tetsuo Handa , Sasha Levin Subject: [PATCH 4.19 191/323] debugobjects: Recheck debug_objects_enabled before reporting Date: Wed, 9 Aug 2023 12:40:29 +0200 Message-ID: <20230809103706.921209533@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103658.104386911@linuxfoundation.org> References: <20230809103658.104386911@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Tetsuo Handa [ Upstream commit 8b64d420fe2450f82848178506d3e3a0bd195539 ] syzbot is reporting false a positive ODEBUG message immediately after ODEBUG was disabled due to OOM. [ 1062.309646][T22911] ODEBUG: Out of memory. ODEBUG disabled [ 1062.886755][ T5171] ------------[ cut here ]------------ [ 1062.892770][ T5171] ODEBUG: assert_init not available (active state 0) object: ffffc900056afb20 object type: timer_list hint: process_timeout+0x0/0x40 CPU 0 [ T5171] CPU 1 [T22911] -------------- -------------- debug_object_assert_init() { if (!debug_objects_enabled) return; db = get_bucket(addr); lookup_object_or_alloc() { debug_objects_enabled = 0; return NULL; } debug_objects_oom() { pr_warn("Out of memory. ODEBUG disabled\n"); // all buckets get emptied here, and } lookup_object_or_alloc(addr, db, descr, false, true) { // this bucket is already empty. return ERR_PTR(-ENOENT); } // Emits false positive warning. debug_print_object(&o, "assert_init"); } Recheck debug_object_enabled in debug_print_object() to avoid that. Reported-by: syzbot Suggested-by: Thomas Gleixner Signed-off-by: Tetsuo Handa Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/492fe2ae-5141-d548-ebd5-62f5fe2e57f7@I-love.SAKURA.ne.jp Closes: https://syzkaller.appspot.com/bug?extid=7937ba6a50bdd00fffdf Signed-off-by: Sasha Levin --- lib/debugobjects.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 5f23d896df55a..62d095fd0c52a 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -371,6 +371,15 @@ static void debug_print_object(struct debug_obj *obj, char *msg) struct debug_obj_descr *descr = obj->descr; static int limit; + /* + * Don't report if lookup_object_or_alloc() by the current thread + * failed because lookup_object_or_alloc()/debug_objects_oom() by a + * concurrent thread turned off debug_objects_enabled and cleared + * the hash buckets. + */ + if (!debug_objects_enabled) + return; + if (limit < 5 && descr != descr_test) { void *hint = descr->debug_hint ? descr->debug_hint(obj->object) : NULL; -- 2.39.2