From da58405860b992d2bb21ebae5d685fe3204dd3f0 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 18 Mar 2010 11:56:54 +0000 Subject: [PATCH] drm: Return ENODEV if the inode mapping changes Replace a BUG_ON with an error code in the event that the inode mapping changes between calls to drm_open. This may happen for instance if udev is loaded subsequent to the original opening of the device: [ 644.291870] kernel BUG at drivers/gpu/drm/drm_fops.c:146! [ 644.291876] invalid opcode: 0000 [#1] SMP [ 644.291882] last sysfs file: /sys/kernel/uevent_seqnum [ 644.291888] [ 644.291895] Pid: 7276, comm: lt-cairo-test-s Not tainted 2.6.34-rc1 #2 N150/N210/N220 /N150/N210/N220 [ 644.291903] EIP: 0060:[] EFLAGS: 00210283 CPU: 0 [ 644.291912] EIP is at drm_open+0x4b1/0x4e2 [ 644.291918] EAX: f72d8d18 EBX: f790a400 ECX: f73176b8 EDX: 00000000 [ 644.291923] ESI: f790a414 EDI: f790a414 EBP: f647ae20 ESP: f647adfc [ 644.291929] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 644.291937] Process lt-cairo-test-s (pid: 7276, ti=f647a000 task=f73f5c80 task.ti=f647a000) [ 644.291941] Stack: [ 644.291945] 00000000 f7bb7400 00000080 f6451100 f73176b8 f6479214 f6451100 f73176b8 [ 644.291957] <0> c1297ce0 f647ae34 c11c6c04 f73176b8 f7949800 00000000 f647ae54 c1080ac5 [ 644.291969] <0> f7949800 f6451100 00000000 f6451100 f73176b8 f6452780 f647ae70 c107d1e6 [ 644.291982] Call Trace: [ 644.291991] [] ? drm_stub_open+0x8a/0xb8 [ 644.292000] [] ? chrdev_open+0xef/0x106 [ 644.292008] [] ? __dentry_open+0xd4/0x1a6 [ 644.292015] [] ? nameidata_to_filp+0x31/0x45 [ 644.292022] [] ? chrdev_open+0x0/0x106 [ 644.292030] [] ? do_last+0x346/0x423 [ 644.292037] [] ? do_filp_open+0x190/0x415 [ 644.292046] [] ? handle_mm_fault+0x214/0x710 [ 644.292053] [] ? do_sys_open+0x4d/0xe9 [ 644.292061] [] ? do_page_fault+0x211/0x23f [ 644.292068] [] ? sys_open+0x23/0x2b [ 644.292075] [] ? sysenter_do_call+0x12/0x26 [ 644.292079] Code: 89 f0 89 55 dc e8 8d 96 0a 00 8b 45 e0 8b 55 dc 83 78 04 01 75 28 8b 83 18 02 00 00 85 c0 74 0f 8b 4d ec 3b 81 ac 00 00 00 74 13 <0f> 0b eb fe 8b 4d ec 8b 81 ac 00 00 00 89 83 18 02 00 00 89 f0 [ 644.292143] EIP: [] drm_open+0x4b1/0x4e2 SS:ESP 0068:f647adfc [ 644.292175] ---[ end trace 2ddd476af89a60fa ]--- Signed-off-by: Chris Wilson Cc: stable@kernel.org Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_fops.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index 08d14df3bb42..4804872f8b19 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -140,14 +140,16 @@ int drm_open(struct inode *inode, struct file *filp) spin_unlock(&dev->count_lock); } out: - mutex_lock(&dev->struct_mutex); - if (minor->type == DRM_MINOR_LEGACY) { - BUG_ON((dev->dev_mapping != NULL) && - (dev->dev_mapping != inode->i_mapping)); - if (dev->dev_mapping == NULL) - dev->dev_mapping = inode->i_mapping; + if (!retcode) { + mutex_lock(&dev->struct_mutex); + if (minor->type == DRM_MINOR_LEGACY) { + if (dev->dev_mapping == NULL) + dev->dev_mapping = inode->i_mapping; + else if (dev->dev_mapping != inode->i_mapping) + retcode = -ENODEV; + } + mutex_unlock(&dev->struct_mutex); } - mutex_unlock(&dev->struct_mutex); return retcode; } -- 2.30.2