From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (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 ADF462C21E7 for ; Wed, 3 Dec 2025 08:35:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764750930; cv=none; b=NuoIH9wiBJscbnhMa9ePO3dj4HryuWUx8DSb2CtGbW++UqCPCEdzEcx7ppyr1Iz2IJCqJnlCZ6JK7G10m4pB70qCZrr4WqUfWTuS9d4Xv+dgf9dvfmOt7g4PI890N2+CmsWpdiugsFRkb4uPTCRWSkYfNOLjcWWuBGNfiXl/nxM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764750930; c=relaxed/simple; bh=oH8yQGzzXZcaEdMki6U8Ym7VH1MYIj3PoyhKbQTCAts=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=WXmLSkEgJgPZRq6tJY15DKLuGbA5BQ2KcwdXoXE8GLfXDxAyQ8DkimtTYO7ovMD41LJuLguMIP26bTbQkdv6SglDXFN0IdyLlzUv2cQ51Csl2DYYDVhU3Ivsy4oIll3r8ti2lnyNlCMefyHocyZuzewNb+s7srNMvIfw3P//py8= 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=gug20vqe; arc=none smtp.client-ip=209.85.214.176 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="gug20vqe" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-29806bd47b5so36871695ad.3 for ; Wed, 03 Dec 2025 00:35:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1764750928; x=1765355728; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=Tf1nnmSZ7EAkZS208EkRia8wUwwUIdfQx1MPOO30xbk=; b=gug20vqeA3AFps5FzKYVayJWH2ePPE51MlAfItpMlr3DPjLBhQ60JjsfPZ73LDf3eI +yQ80KrgPmkUUKiJer6I2/JHqIoRlva3M/hycmq2SGfXtyT4PLyP+lvccvoTsXfGZEXT c2B4Wj0Ui9aGzHoiWVxsV3U8Djks6sWODisINQ6PoCq58hQW6+rukphOz+iLtbvwVDlm /Z3XTr2urn0wBIZGg1FQ/+/K4ExuseBvSAlP/AZrrZ3QMcWjE6KT3Nu5rQtlyGI70poV qPTTwY6GtrYne6ACzzGLlsm0CaDwE941T1WxBgh6aCgFhT1pthWpbitZAuoD264VOP+J zNLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764750928; x=1765355728; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Tf1nnmSZ7EAkZS208EkRia8wUwwUIdfQx1MPOO30xbk=; b=frjAWhw0UTus1K4oSQbGvTorVRco6xn5uSV4DWvMxQYTalK8UQi5K8mDN00FC1lakW lezWaFxbL+d9JSZj/l8Fcw4e0280RTQIYEKK0Yf/zu7hxpZC5sG3rQqihHD0IkVVVuXr 5vR5O9i6m4pYpW9bD7d6HcBUWs42pxNOJlMfSoP6CnYO5Z56edlz5OidJEoGX3r+ea31 z+2xXF8wffjb8mExeUro0CZI3mieCcF2lsjt0Z9h2bBa9JSG/pjYR7dXKpsIinA9PPpa wFAtxrdc+YiXS1M5bNL0cRk2D6y4oeKtBdv0FtGPqjKI090xRtdwigjHt0pkQBsj89hX RxOQ== X-Forwarded-Encrypted: i=1; AJvYcCV1vXdoi1pth7Uf1Gpr3+fw7HKR6lQuSxP7uqU16DGDA6PsC4AwDfKuiNk4k2Ok00PK8ZH2gCKh+iEWm4mu@lists.linux.dev X-Gm-Message-State: AOJu0YyZCzYtyJGSWpH3MQoSR+fuXzzk96BeN9Q9yHO0xaO7b6lOdkAC FfGpLTXEaphzTk+W+NCIIL4wwKK4Cj8uog0aK0KkzjG3lQ4a/F7RM/UT X-Gm-Gg: ASbGncvIBp5MWCOl1djLViT9alab5htfLkbkERTqsbB9hwZN+F2eSWmWInPZbdMsTGg Zk3Am13oRa2iCNYpNfs33LBCOaQFNhJ8TdgB7tIS/UjNqo52QNSZy88HsRVNBPRlJ1FEsmZEyYB gDVUKoFhK+CU+xzOkJx4fp8QZl5Z/3/UFDrez2Hgk6D5YlgaOrSsaLbwmh1PlUE5UM8F/r749au v8DkI+l2rb5vawNr/tFg765Lcr7iH9hZMqz5X/8zl1/gqeRPVveQmCKmSdV17fTRFY8Oqux3FSh 7zuygVysVMEiESiVGr+qTSnZfgmqC1WvjzyWdYs66zbZm7LwynXfyaUaXSIE8cSYEQBd6kKLZf4 YZgAcrJvDBsJn7rRdkx7OaETDP5ENqA4B8lmueQig3EiRKY5Y1oe3BTETAgjpw49wpXlCA+SS/3 is7bdo9Pal3qJIZsoxWnlVm66GScY= X-Google-Smtp-Source: AGHT+IEAKboQRaFs/KJv+Ej0IKMc71NAUxirzYj6FDqusBLvHmU6/h0Z+CFr40zf6m6cyoyFqNmkVg== X-Received: by 2002:a17:903:11c3:b0:297:d6c2:d06 with SMTP id d9443c01a7336-29d682f4d7dmr18117135ad.20.1764750927866; Wed, 03 Dec 2025 00:35:27 -0800 (PST) Received: from pavan.localdomain ([49.37.149.66]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7d1520a48b2sm19390530b3a.28.2025.12.03.00.35.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Dec 2025 00:35:27 -0800 (PST) From: Pavan Kumar Yalagada To: parthiban.veerasooran@microchip.com, christian.gromm@microchip.com, gregkh@linuxfoundation.org Cc: dan.carpenter@linaro.org, laurent.pinchart+renesas@ideasonboard.com, hverkuil+cisco@kernel.org, linux-staging@lists.linux.dev, linux-media@vger.kernel.org, pavankumaryalagada@gmail.com Subject: [PATCH v5] staging: most: video: prevent probes during component exit Date: Wed, 3 Dec 2025 03:34:11 -0500 Message-ID: <20251203083411.7072-1-pavankumaryalagada@gmail.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When comp_exit() runs, comp_probe_channel() could still add new devices to video_devices, creating a race and potentially leaving the list in an inconsistent state. This patch prevents new devices from being added while exiting by: - comp_probe_channel() checks comp_exiting before modifying video_devices. if (comp_exiting) { spin_unlock_irq(&list_lock); ret = -BUSY; goto err_unreg; } This ensures that all partially created resources are properly freed and no new channels are allowed while the driver is being unloaded. Signed-off-by: Pavan Kumar Yalagada --- v5: - Removed unlikely() macro since this is not fast path. - Added comp_unregister_videodev() to err_unreg cleanup patch. - Removed blank line in comp_exit(). v4: - Used unlikely() for the comp_exiting check to optimize branch prediction. - Removed err_cleanup and use err_unreg for proper cleanup of partially initialized mdev/v4l2 structures. - Removed redundant spinlock usage around 'comp_exiting = true;' comp_exit(). - Removed explicit kfree(mdev) in comp_exit() loop. v3: - comp_exiting flag update and memory cleanup for early exits. - Commit message clarified for reviewers. - Removed WARN/BUG as it becomes unnecessary. --- drivers/staging/most/video/video.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/staging/most/video/video.c b/drivers/staging/most/video/video.c index 32f71d9a9cf7..11e63f5d5b84 100644 --- a/drivers/staging/most/video/video.c +++ b/drivers/staging/most/video/video.c @@ -60,6 +60,8 @@ static inline struct comp_fh *to_comp_fh(struct file *filp) static LIST_HEAD(video_devices); static DEFINE_SPINLOCK(list_lock); +static bool comp_exiting; + static inline bool data_ready(struct most_video_dev *mdev) { return !list_empty(&mdev->pending_mbos); @@ -498,11 +500,17 @@ static int comp_probe_channel(struct most_interface *iface, int channel_idx, goto err_unreg; spin_lock_irq(&list_lock); + if (comp_exiting) { + spin_unlock_irq(&list_lock); + ret = -EBUSY; + goto err_unreg; + } list_add(&mdev->list, &video_devices); spin_unlock_irq(&list_lock); return 0; err_unreg: + comp_unregister_videodev(mdev); v4l2_device_disconnect(&mdev->v4l2_dev); v4l2_device_put(&mdev->v4l2_dev); return ret; @@ -555,6 +563,8 @@ static void __exit comp_exit(void) { struct most_video_dev *mdev, *tmp; + comp_exiting = true; + /* * As the mostcore currently doesn't call disconnect_channel() * for linked channels while we call most_deregister_component() @@ -575,7 +585,6 @@ static void __exit comp_exit(void) most_deregister_configfs_subsys(&comp); most_deregister_component(&comp); - BUG_ON(!list_empty(&video_devices)); } module_init(comp_init); -- 2.47.3