From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 33A43288B2; Sat, 12 Sep 2026 10:28:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789208936; cv=none; b=HnE7YeMxc5IBf6q04zTbECS9c34d+35cColoBjW6jmDfkHns+6r8Zk9f95Am/jEQpFUVwjfxW6YqZfvLQVJeg4MpfBxtUb9zkp1OHn8/lY8w30cOyz2YeJHhERDu2i9sG7VSUd5r7RimWGuWA3/VeAGEucCD7yBHLbb1hO2zI8c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789208936; c=relaxed/simple; bh=JQozQI44vokzWDMNnqp9HFMB8kf/mo9Jwbqo6UK3QXw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XPElXqcWqprybY9KSenlGUHL/pJkmjG0SSPAnRLtAO3NQmkzc05IqUYC2l462z1B7mGcWg6x4xy5IJ5aL/BHMOZPYwJmVkHRWgfBGxs/RsdbhYIg7PmSdClWjpwG8zptqhhvyhbUnpYBAgDD4nlcVQkyuBn2JwunHqkTPiF2EjU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lW+DD/WX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="lW+DD/WX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C84851F0089A; Sat, 12 Sep 2026 10:28:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789208935; bh=HHthf4iCSXf3eazYLGHCqF91Wud/PeyLjd/DktHrLtQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lW+DD/WXRDFT4E1cinUB5KWX0QBGiwfT+bNge1KJIUd6ILV33PpBB5z+Ivvt9nOjE oWoX9Zr57jgem0acpV3s8tbxiy57HAn49VpjBLYrSzjdOlnpawJYSG0Wrofos7kGLJ gNEXsriFrFM9eRwVfymjVfFu/LMzx4Wj0LorjHFU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Naveen Kumar Chaudhary , "Peter Zijlstra (Intel)" , Waiman Long , Dmitry Ilvokhin , Sasha Levin Subject: [PATCH 6.18 0718/1518] locking/lockdep: Fix NULL pointer dereference in __lock_set_class() Date: Sat, 12 Sep 2026 08:48:07 +0200 Message-ID: <20260912065639.677837637@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Naveen Kumar Chaudhary [ Upstream commit 7577e00b9ab506202b9f1a33de3cc8cc6413a4db ] register_lock_class() can return NULL when the lock class pool is exhausted, graph_lock() fails, or key validation fails. However, __lock_set_class() uses the return value directly in pointer arithmetic without a NULL check: class = register_lock_class(lock, subclass, 0); hlock->class_idx = class - lock_classes; If class is NULL, this computes a wild offset that corrupts hlock->class_idx. The subsequent reacquire_held_locks() call will invoke hlock_class() with this corrupted index, leading to a NULL or out-of-bounds pointer dereference. Add the missing NULL check, consistent with how __lock_acquire() already handles this case at the same call site. Fixes: 64aa348edc61 ("lockdep: lock_set_subclass - reset a held lock's subclass") Signed-off-by: Naveen Kumar Chaudhary Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Waiman Long Reviewed-by: Dmitry Ilvokhin Link: https://patch.msgid.link/h2kfw43n4527x6mgi2lwpz2rieqnfzgictpv4wr5nyfjkc47co@2r5vz4uz44db Signed-off-by: Sasha Levin --- kernel/locking/lockdep.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 2d4c5bab5af88..e0de811148242 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -5437,6 +5437,8 @@ __lock_set_class(struct lockdep_map *lock, const char *name, lock->wait_type_outer, lock->lock_type); class = register_lock_class(lock, subclass, 0); + if (!class) + return 0; hlock->class_idx = class - lock_classes; curr->lockdep_depth = i; -- 2.53.0