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 E6F8C3002C8 for ; Tue, 14 Oct 2025 16:06:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760457989; cv=none; b=hAZ34o5QjeZGVHszuOZz5ebBGLSTutHWDUMvQU144JJ/uEeGXuuJzRdQSCTbGGyycBaXvTqasIv10kb2X80mVm0akQHl1v/Oo+qLrRZ0UrEyDKswHBksJblZdJ0YBTfzWW3PjAmD35aQFF6vkVAkypQ6RvZyoDLZGQTy+osRLS0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760457989; c=relaxed/simple; bh=9tc4qlNTzRhbMSM8TPIEF2fZZ2R73vXPhd7B1Dg7PkE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=TRQytNoB5lWY1Q0alR6PfSS3TaEc38hAAzt/mK48TfJkP3bu9ljApekMZ9foceQbDlCkUR2bnQuLgdJQ3TgejvUVXDWQI2Kx0ytYH/I9h3Tni2FEJ7Gzmakcs7539x0SgI4orzO/rQHz2yEoJVcS5DrfSS4Qs1zDdYLorVsIBCA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g8icaYPx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g8icaYPx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A12A3C113D0; Tue, 14 Oct 2025 16:06:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760457987; bh=9tc4qlNTzRhbMSM8TPIEF2fZZ2R73vXPhd7B1Dg7PkE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g8icaYPxYz++t5v1lbUp51ApTh7tflz8AbkTbFCv3YVhNuR9hViZfJJHPxGCQ85OT U4Ni1OgkCM8fuwYYIYoBdpE7cuagh+XOqLUSrld6J7DplkP9fuVpNQQIcVkW2PhCME 4aWJPtnq6ouJK396Du+0OATzniow6rWA7ht9LXwk+oVRrATff9BjDFcBFCvLrt9llw 9/utjsLDo4SEqhwcBKcPkMCOA8ifGiLYNct3r3Asg3OAOZ0R0fsscJEmi3G6MeFLbF l0jUjg9THdGNUql0kgSrpMIWAJo1DMMqYgHZK89BL8gND4hBzlPSTUOscGp5ctisk0 b6Tj2l1ncZrSQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Shin'ichiro Kawasaki , Manivannan Sadhasivam , Damien Le Moal , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , Sasha Levin Subject: [PATCH 6.6.y 2/2] PCI: endpoint: pci-epf-test: Add NULL check for DMA channels before release Date: Tue, 14 Oct 2025 12:06:18 -0400 Message-ID: <20251014160618.158328-2-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251014160618.158328-1-sashal@kernel.org> References: <2025101340-passably-rounding-59df@gregkh> <20251014160618.158328-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Shin'ichiro Kawasaki [ Upstream commit 85afa9ea122dd9d4a2ead104a951d318975dcd25 ] The fields dma_chan_tx and dma_chan_rx of the struct pci_epf_test can be NULL even after EPF initialization. Then it is prudent to check that they have non-NULL values before releasing the channels. Add the checks in pci_epf_test_clean_dma_chan(). Without the checks, NULL pointer dereferences happen and they can lead to a kernel panic in some cases: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050 Call trace: dma_release_channel+0x2c/0x120 (P) pci_epf_test_epc_deinit+0x94/0xc0 [pci_epf_test] pci_epc_deinit_notify+0x74/0xc0 tegra_pcie_ep_pex_rst_irq+0x250/0x5d8 irq_thread_fn+0x34/0xb8 irq_thread+0x18c/0x2e8 kthread+0x14c/0x210 ret_from_fork+0x10/0x20 Fixes: 8353813c88ef ("PCI: endpoint: Enable DMA tests for endpoints with DMA capabilities") Fixes: 5ebf3fc59bd2 ("PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data") Signed-off-by: Shin'ichiro Kawasaki [mani: trimmed the stack trace] Signed-off-by: Manivannan Sadhasivam Reviewed-by: Damien Le Moal Reviewed-by: Krzysztof Wilczyński Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20250916025756.34807-1-shinichiro.kawasaki@wdc.com Signed-off-by: Sasha Levin --- drivers/pci/endpoint/functions/pci-epf-test.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c index ff4ca6ea5cb8e..4cf20ca25ea74 100644 --- a/drivers/pci/endpoint/functions/pci-epf-test.c +++ b/drivers/pci/endpoint/functions/pci-epf-test.c @@ -282,15 +282,20 @@ static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test) if (!epf_test->dma_supported) return; - dma_release_channel(epf_test->dma_chan_tx); - if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { + if (epf_test->dma_chan_tx) { + dma_release_channel(epf_test->dma_chan_tx); + if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { + epf_test->dma_chan_tx = NULL; + epf_test->dma_chan_rx = NULL; + return; + } epf_test->dma_chan_tx = NULL; - epf_test->dma_chan_rx = NULL; - return; } - dma_release_channel(epf_test->dma_chan_rx); - epf_test->dma_chan_rx = NULL; + if (epf_test->dma_chan_rx) { + dma_release_channel(epf_test->dma_chan_rx); + epf_test->dma_chan_rx = NULL; + } } static void pci_epf_test_print_rate(struct pci_epf_test *epf_test, -- 2.51.0