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 E1809343893; Sat, 12 Sep 2026 14:45:00 +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=1789224302; cv=none; b=nwWoPny4IHDwVULSo7ovs5/n4TbuSY9fVdhZHEGhmWfQsxsJKirhc5ms0+yRhXfK0oeVXpmoFyo1bNkk9vw7iqeVrCz0EuZqkIqQTMV8212hOkd/JsfBCknTEPM1z0HBPyTHWhtJbRB1+WCTdpyfxFAQ+4WZ3XiV0k2Q4rulu8Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789224302; c=relaxed/simple; bh=3SfEX8bzoG3EU9CjnWJHEdahtl7+i9tKoTzpUrFNL0c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=V3nkfk3MxAxPo+Vxa+P9RfKZa6XvZFBzqbTKnswRUifShCcA1tWwqoAPuDzidym4cd2u3o84Ud38OopKijb/muXPLfbQuFT8BYzG0gWPUQa414iMBsqLhf8Z83SYC20w2FnpcFUv6MFecLTK1Mloln+mAihwSCOhIvXYjVlb6G8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dOt3bUQA; 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="dOt3bUQA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E28DC1F000FF; Sat, 12 Sep 2026 14:44:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789224300; bh=wf+dfM2m8XHEZe8/L5unIIisvOG04edRtDj/TkhWU/g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dOt3bUQAEYs4BCYxcLvHU165mvrQCvHEUBpi+wTsQO+V1H+E7EJK5mAcNzQkvdL7A qN88ziNIzxHP/GfEmKvlfNUYWYCyaM8N1qLRNboZTj+/k/oghGQWiAfTWK9cDlsubT V65Ddcgk9ugVTJhmz27mO0RxUuQOdgwK+gACCS6U= 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 6.6 0966/1424] locking/lockdep: Fix NULL pointer dereference in __lock_set_class() Date: Sat, 12 Sep 2026 08:56:38 +0200 Message-ID: <20260912065628.945669667@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@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 6.6-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 9419a79e8833f..b16e699cee9fe 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -5331,6 +5331,8 @@ __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