[media] videobuf2: Add missing lock held on vb2_fop_release
vb2_fop_release does not hold the lock although it is modifying the queue->owner field. This could lead to race conditions on the vb2_perform_io function when multiple applications are accessing the video device via read/write API: [ 308.297741] BUG: unable to handle kernel NULL pointer dereference at 0000000000000260 [ 308.297759] IP: [<ffffffffa07a9fd2>] vb2_perform_fileio+0x372/0x610 [videobuf2_core] [ 308.297794] PGD 159719067 PUD 158119067 PMD 0 [ 308.297812] Oops: 0000 #1 SMP [ 308.297826] Modules linked in: qt5023_video videobuf2_dma_sg qtec_xform videobuf2_vmalloc videobuf2_memops videobuf2_core qtec_white qtec_mem gpio_xilinx qtec_cmosis qtec_pcie fglrx(PO) spi_xilinx spi_bitbang qt5023 [ 308.297888] CPU: 1 PID: 2189 Comm: java Tainted: P O 3.11.0-qtec-standard #1 [ 308.297919] Hardware name: QTechnology QT5022/QT5022, BIOS PM_2.1.0.309 X64 05/23/2013 [ 308.297952] task: ffff8801564e1690 ti: ffff88014dc02000 task.ti: ffff88014dc02000 [ 308.297962] RIP: 0010:[<ffffffffa07a9fd2>] [<ffffffffa07a9fd2>] vb2_perform_fileio+0x372/0x610 [videobuf2_core] [ 308.297985] RSP: 0018:ffff88014dc03df8 EFLAGS: 00010202 [ 308.297995] RAX: 0000000000000000 RBX: ffff880158a23000 RCX: dead000000100100 [ 308.298003] RDX: 0000000000000000 RSI: dead000000200200 RDI: 0000000000000000 [ 308.298012] RBP: ffff88014dc03e58 R08: 0000000000000000 R09: 0000000000000001 [ 308.298020] R10: ffffea00051e8380 R11: ffff88014dc03fd8 R12: ffff880158a23070 [ 308.298029] R13: ffff8801549040b8 R14: 0000000000198000 R15: 0000000001887e60 [ 308.298040] FS: 00007f65130d5700(0000) GS:ffff88015ed00000(0000) knlGS:0000000000000000 [ 308.298049] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 308.298057] CR2: 0000000000000260 CR3: 0000000159630000 CR4: 00000000000007e0 [ 308.298064] Stack: [ 308.298071] ffff880156416c00 0000000000198000 0000000000000000 ffff880100000001 [ 308.298087] ffff88014dc03f50 00000000810a79ca 0002000000000001 ffff880154904718 [ 308.298101] ffff880156416c00 0000000000198000 ffff880154904338 ffff88014dc03f50 [ 308.298116] Call Trace: [ 308.298143] [<ffffffffa07aa3c4>] vb2_read+0x14/0x20 [videobuf2_core] [ 308.298198] [<ffffffffa07aa494>] vb2_fop_read+0xc4/0x120 [videobuf2_core] [ 308.298252] [<ffffffff8154ee9e>] v4l2_read+0x7e/0xc0 [ 308.298296] [<ffffffff8116e639>] vfs_read+0xa9/0x160 [ 308.298312] [<ffffffff8116e882>] SyS_read+0x52/0xb0 [ 308.298328] [<ffffffff81784179>] tracesys+0xd0/0xd5 [ 308.298335] Code: e5 d6 ff ff 83 3d be 24 00 00 04 89 c2 4c 8b 45 b0 44 8b 4d b8 0f 8f 20 02 00 00 85 d2 75 32 83 83 78 03 00 00 01 4b 8b 44 c5 48 <8b> 88 60 02 00 00 85 c9 0f 84 b0 00 00 00 8b 40 58 89 c2 41 89 [ 308.298487] RIP [<ffffffffa07a9fd2>] vb2_perform_fileio+0x372/0x610 [videobuf2_core] [ 308.298507] RSP <ffff88014dc03df8> [ 308.298514] CR2: 0000000000000260 [ 308.298526] ---[ end trace e8f01717c96d1e41 ]--- Signed-off-by: Ricardo Ribalda <ricardo.ribalda@gmail.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
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@ -549,7 +549,7 @@ static int fimc_capture_release(struct file *file)
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vc->streaming = false;
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}
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ret = vb2_fop_release(file);
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ret = _vb2_fop_release(file, NULL);
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if (close) {
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clear_bit(ST_CAPT_BUSY, &fimc->state);
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@ -546,7 +546,7 @@ static int fimc_lite_release(struct file *file)
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mutex_unlock(&entity->parent->graph_mutex);
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}
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vb2_fop_release(file);
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_vb2_fop_release(file, NULL);
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pm_runtime_put(&fimc->pdev->dev);
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clear_bit(ST_FLITE_SUSPENDED, &fimc->state);
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@ -2632,16 +2632,29 @@ int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)
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}
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EXPORT_SYMBOL_GPL(vb2_fop_mmap);
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int vb2_fop_release(struct file *file)
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int _vb2_fop_release(struct file *file, struct mutex *lock)
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{
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struct video_device *vdev = video_devdata(file);
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if (file->private_data == vdev->queue->owner) {
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if (lock)
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mutex_lock(lock);
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vb2_queue_release(vdev->queue);
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vdev->queue->owner = NULL;
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if (lock)
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mutex_unlock(lock);
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}
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return v4l2_fh_release(file);
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}
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EXPORT_SYMBOL_GPL(_vb2_fop_release);
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int vb2_fop_release(struct file *file)
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{
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struct video_device *vdev = video_devdata(file);
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struct mutex *lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
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return _vb2_fop_release(file, lock);
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}
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EXPORT_SYMBOL_GPL(vb2_fop_release);
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ssize_t vb2_fop_write(struct file *file, const char __user *buf,
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@ -491,6 +491,7 @@ int vb2_ioctl_expbuf(struct file *file, void *priv,
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int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma);
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int vb2_fop_release(struct file *file);
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int _vb2_fop_release(struct file *file, struct mutex *lock);
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ssize_t vb2_fop_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos);
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ssize_t vb2_fop_read(struct file *file, char __user *buf,
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