From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f43.google.com (mail-wr1-f43.google.com [209.85.221.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 75BFE41A794 for ; Fri, 31 Jul 2026 18:18:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785521937; cv=none; b=BMo4UtPOlkbf8WO0pLbEGMabMYTt0HXE5UTfQq+aLhTQV2eI1logoOvzcZ5RWkm7YhhCDOuCrDRSoi6LQ+mwqor9TyNVxjigEbkOlnBl1t3q1aAHJwLolDTNrGqdN5ZgmDU5Yl7pkAh8VR2f21qm5q0YNqqZmrmY5rpeqOxJZ1E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785521937; c=relaxed/simple; bh=f2WgAKIx0zZc7BGy0VsUPDEiddYh46CfX4wE+IV1Le0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VU2WlJ7eRa2koTslHNVLmyUyXaT8i8UtOGQIlnoM0XkgWhMc/5kzbNxtBsxzE5q9b4nULGiIGCRIAQrucCvlwO3cPj5Jbb/J0pP1+E/JC5eulDaLqf+IOWNIumh/6DtPwpMP5tIAU2wDnGAilTWcKIdkIIEqPPwhKOy2ystE468= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=PRIxqODN; arc=none smtp.client-ip=209.85.221.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PRIxqODN" Received: by mail-wr1-f43.google.com with SMTP id ffacd0b85a97d-47640541585so1002731f8f.1 for ; Fri, 31 Jul 2026 11:18:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785521934; x=1786126734; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=ou5GQthySEEBs7kf/0E67tbXvLbnV4y0XvYiP2W//3Q=; b=PRIxqODNBNx0ccr1QEaEoeiTolyTSzYdGj1uB2+6REPqpTrU+bplor9zLzJUmXBa1Y yzSC4jFuIJAAHtReF8pB8iQwPaMhQuqQC7YbyAigqSVm3pTAALmTzYsdCbW1CSOamYUj J2WnZskgvCSDV0zmps95mnOmq6hy0U6Sm9OrvMvLT/UrbSW5/4QTQa+yB011LSlfqRzK yxsmMiSpJf48nzHuMHwctWuJaG78evF9JsKN+ffwsFdesAbp+/s4sv/mlQ9u69I+gHRr 2LQPXT7nuye31Vem/9crmbXsdZAvccKvhF/MJgD1EF/XR/5Wew0EUCOJLvGrXVWRbGVB F7Aw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785521934; x=1786126734; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=ou5GQthySEEBs7kf/0E67tbXvLbnV4y0XvYiP2W//3Q=; b=dlizUO8igqaOVIGXJ8hvELYBnQ90+l3C9CEK2zjY636djf3IdR+p+6WzJfPZPwWMHj QVzy4wP+3T++jJBmWp8Dg1m0h/38ywCKtyuXoUiQB9QbmzuY1+w7sLiSyUN+mWyuLtPm HSf9sckx7RfdRTYejCspEsLhN6+NojrkQ/Dkzbscyq4+lzGO5YGXbvykdeT9/9D6SjNl uY56/jf73hx8jcSLBq7aRZc8CceOXhvazTmOYSh6UIz8OLYb9VBFLIvnK3iJrzBbKkqG ZfxK0V4akvl8902LU8BelDIScyMWu3KHSSlMhcSoCRqWcT3OO9jvAw5IIrh3K5SnUupM snCg== X-Forwarded-Encrypted: i=1; AHgh+Rq3G8gDu5VE/HWWaREEX+gZT77KconcbOASDeQqnE+iyUwLxUw62NTPo7GgejmYY/ZtQsx0hCQ0nyHERxg=@vger.kernel.org X-Gm-Message-State: AOJu0Yy6LxK2y0n6+RP2e7qSppPBRt7jTJt1QuQDWNBkBF0QPGXrGGQc THhoY8r1Xu4Gorvd4p+K8D5dguWDSPdBKB0Mf1mSZFTfUXcJE6POeWKQ X-Gm-Gg: AR+sD11dlEch7bJbjao0mMSlDoLwllRtj61ENsJHFG+Lye1g+GbYXzfP4AF/P5q/xOX c9rh+ERnxu4Xkud77rXU8DXKZtempdzonm7SFS2SvES1oW97k8g8WB9ZML6cy8HLyVrIlg9MUSZ LyitiiCVVVfWF6FPq2NIVucTf3b99vcItx0XP/Gl+EeUkLusDo7B1zSbqGmtS0PJM1M3N8uOxgw 6bRnquO6gYQASJWovQc8RJgmqB+Ytssoye/CKahE8GHPH11MTyKloSK08mvyYz7jwqT72pAVVTo cpq4l4cygrsjQYko91mF8Tkh8x3pdskWRHNoBxjJTfWcEQzXuTvZ0phTOSm18318TKwThqELrUx d732btijAzN6bP3eDpuQzAzZUJht3gInKhHGdJsvwWTeMgYGohh1Wmfuo9oslvbMrRvLVb7nlpT PFZLKvumbVdHqluSp+Qt/zygI9zjkSXYB2hNEn2QBA7iA/s6vTZBDnMZpgk6L/4kxgZyFJqdXcs B8CjM/ot6Dx7QfQE2myIakCtCzZrpq90zoVfyLHTykZiddkXpiPYjoOffSATUPGKm5quXE6j3DZ u1qn8hfdenKB4uYGmY1P7pnesDBd4KQJf/ywX73rd2A6+BIKBLDqBJaNG2ZMTmNEfMiY+Tm4AoU jBHs= X-Received: by 2002:a05:6000:29d7:b0:475:3a97:8e3c with SMTP id ffacd0b85a97d-47fd72b08demr1120224f8f.18.1785521933729; Fri, 31 Jul 2026 11:18:53 -0700 (PDT) Received: from localhost.localdomain (dynamic-2a02-3100-a8d0-bc01-6d31-3d12-3a11-d2d0.310.pool.telefonica.de. [2a02:3100:a8d0:bc01:6d31:3d12:3a11:d2d0]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47fd41d1756sm7293694f8f.4.2026.07.31.11.18.52 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 31 Jul 2026 11:18:53 -0700 (PDT) From: Karl Mehltretter To: Greg Kroah-Hartman , Jiri Slaby Cc: Karl Mehltretter , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 2/5] serial: core: clear freed pointers on uart_register_driver() failure Date: Fri, 31 Jul 2026 20:18:41 +0200 Message-Id: <20260731181844.11330-3-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20260731181844.11330-1-kmehltretter@gmail.com> References: <20260731181844.11330-1-kmehltretter@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit uart_register_driver() leaves drv->state pointing to freed memory when tty_alloc_driver() fails. If tty_register_driver() fails, drv->tty_driver also retains a pointer after its reference is dropped. Drivers that use drv->state as an "already registered" flag can then skip registration on the next probe and pass the freed state to uart_add_one_port(). This issue was found with failslab on QEMU's raspi1ap board by failing registration and binding the PL011 port again. Clear both pointers on their failure paths, as uart_unregister_driver() already does. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Fixes: 9e845abfc8a8 ("serial: fix NULL pointer dereference") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter --- drivers/tty/serial/serial_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 03ee3d038f4e..234976fb2a87 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2777,8 +2777,10 @@ int uart_register_driver(struct uart_driver *drv) for (i = 0; i < drv->nr; i++) tty_port_destroy(&drv->state[i].port); tty_driver_kref_put(normal); + drv->tty_driver = NULL; out_kfree: kfree(drv->state); + drv->state = NULL; out: return retval; } -- 2.53.0