From patchwork Tue Apr 30 18:27:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mans Rullgard X-Patchwork-Id: 794063 Received: from unicorn.mansr.com (unicorn.mansr.com [81.2.72.234]) (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 7FB901802DC for ; Tue, 30 Apr 2024 18:27:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=81.2.72.234 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714501673; cv=none; b=NBp4Gh+yLhkSXniVdWXfEfpjgjBj3SYjj9eXNwwSFFyzfPtaVqFeWiVix/CgAXkst2tmrVjrhLoaUY91ctjlpJwb2+TNthdamv6zLeWmNkzJL66sipXetWgzqeLy69ElNKV5QkN71z/b86fv23YNEQAvN3IoykhX2yGFlstM8c4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714501673; c=relaxed/simple; bh=+26Enj+K/4PtmaKhSDoa6xLK7NIqKIPQRYFitKr3Mao=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=DJK8ljAWxmHo8YQVp7YB2kg6badQw3DWq2DL1F21LRUcQoppbD23Z3WgGLzuFt99R/8aeCDhmsDN3/IQj9wIFaQE8e6Cxtzq9Wl8N/Q7wTAwLn2Hmssf2kW9ofB3gSnHA9yXQJGKUDfgzCK6eumPc36Uy1l8ILLQsuNnDRKTmHo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=mansr.com; spf=pass smtp.mailfrom=mansr.com; arc=none smtp.client-ip=81.2.72.234 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=mansr.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mansr.com Received: from raven.mansr.com (raven.mansr.com [81.2.72.235]) by unicorn.mansr.com (Postfix) with ESMTPS id A0A8D15360; Tue, 30 Apr 2024 19:27:43 +0100 (BST) Received: by raven.mansr.com (Postfix, from userid 51770) id 8286621A4DE; Tue, 30 Apr 2024 19:27:43 +0100 (BST) From: Mans Rullgard To: Mark Brown Cc: David Jander , linux-spi@vger.kernel.org Subject: [PATCH] spi: fix null pointer dereference within spi_sync Date: Tue, 30 Apr 2024 19:27:05 +0100 Message-ID: <20240430182705.13019-1-mans@mansr.com> X-Mailer: git-send-email 2.44.0 Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 If spi_sync() is called with the non-empty queue and the same spi_message is then reused, the complete callback for the message remains set while the context is cleared, leading to a null pointer dereference when the callback is invoked from spi_finalize_current_message(). With function inlining disabled, the call stack might look like this: _raw_spin_lock_irqsave from complete_with_flags+0x18/0x58 complete_with_flags from spi_complete+0x8/0xc spi_complete from spi_finalize_current_message+0xec/0x184 spi_finalize_current_message from spi_transfer_one_message+0x2a8/0x474 spi_transfer_one_message from __spi_pump_transfer_message+0x104/0x230 __spi_pump_transfer_message from __spi_transfer_message_noqueue+0x30/0xc4 __spi_transfer_message_noqueue from __spi_sync+0x204/0x248 __spi_sync from spi_sync+0x24/0x3c spi_sync from mcp251xfd_regmap_crc_read+0x124/0x28c [mcp251xfd] mcp251xfd_regmap_crc_read [mcp251xfd] from _regmap_raw_read+0xf8/0x154 _regmap_raw_read from _regmap_bus_read+0x44/0x70 _regmap_bus_read from _regmap_read+0x60/0xd8 _regmap_read from regmap_read+0x3c/0x5c regmap_read from mcp251xfd_alloc_can_err_skb+0x1c/0x54 [mcp251xfd] mcp251xfd_alloc_can_err_skb [mcp251xfd] from mcp251xfd_irq+0x194/0xe70 [mcp251xfd] mcp251xfd_irq [mcp251xfd] from irq_thread_fn+0x1c/0x78 irq_thread_fn from irq_thread+0x118/0x1f4 irq_thread from kthread+0xd8/0xf4 kthread from ret_from_fork+0x14/0x28 Fix this by also setting message->complete to NULL when the transfer is complete. Fixes: ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync") Signed-off-by: Mans Rullgard --- drivers/spi/spi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 34fca94b2b5b..ca13ca47e745 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -4521,6 +4521,7 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message) wait_for_completion(&done); status = message->status; } + message->complete = NULL; message->context = NULL; return status;