[PATCH 4.9 100/171] drm: bochs: Dont remove uninitialized fbdev framebuffer

Greg Kroah-Hartman
2018-11-08T21:51:10Z

[ Upstream commit 4fa13dbe8c86382a846584e65c47bce09297f75b ]

In the same spirit of the fix for QXL in commit 861078381ba5 ("drm: qxl:
Don't alloc fbdev if emulation is not supported"), prevent the Oops in
the unbind path of Bochs if fbdev emulation is disabled.

[ 112.176009] Oops: 0002 [#1] SMP
[ 112.176009] Modules linked in: bochs_drm
[ 112.176009] CPU: 0 PID: 3002 Comm: bash Not tainted 4.11.0-rc1+ #111
[ 112.176009] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014
[ 112.176009] task: ffff8800743bbac0 task.stack: ffffc90000b5c000
[ 112.176009] RIP: 0010:mutex_lock+0x18/0x30
[ 112.176009] RSP: 0018:ffffc90000b5fc78 EFLAGS: 00010246
[ 112.176009] RAX: 0000000000000000 RBX: 0000000000000260 RCX: 0000000000000000
[ 112.176009] RDX: ffff8800743bbac0 RSI: ffff8800787176e0 RDI: 0000000000000260
[ 112.176009] RBP: ffffc90000b5fc80 R08: ffffffff00000000 R09: 00000000ffffffff
[ 112.176009] R10: ffff88007b463650 R11: 0000000000000000 R12: 0000000000000260
[ 112.176009] R13: ffff8800787176e0 R14: ffffffffa0003068 R15: 0000000000000060
[ 112.176009] FS: 00007f20564c7b40(0000) GS:ffff88007ce00000(0000) knlGS:0000000000000000
[ 112.176009] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 112.176009] CR2: 0000000000000260 CR3: 000000006b89c000 CR4: 00000000000006f0
[ 112.176009] Call Trace:
[ 112.176009] drm_mode_object_unregister+0x1e/0x50
[ 112.176009] drm_framebuffer_unregister_private+0x15/0x20
[ 112.176009] bochs_fbdev_fini+0x57/0x70 [bochs_drm]
[ 112.176009] bochs_unload+0x16/0x50 [bochs_drm]
[ 112.176009] drm_dev_unregister+0x37/0xd0
[ 112.176009] drm_put_dev+0x31/0x60
[ 112.176009] bochs_pci_remove+0x10/0x20 [bochs_drm]
[ 112.176009] pci_device_remove+0x34/0xb0
[ 112.176009] device_release_driver_internal+0x150/0x200
[ 112.176009] device_release_driver+0xd/0x10
[ 112.176009] unbind_store+0x108/0x150
[ 112.176009] drv_attr_store+0x20/0x30
[ 112.176009] sysfs_kf_write+0x32/0x40
[ 112.176009] kernfs_fop_write+0x10b/0x190
[ 112.176009] __vfs_write+0x23/0x120
[ 112.176009] ? security_file_permission+0x36/0xb0
[ 112.176009] ? rw_verify_area+0x49/0xb0
[ 112.176009] vfs_write+0xb0/0x190
[ 112.176009] SyS_write+0x41/0xa0
[ 112.176009] entry_SYSCALL_64_fastpath+0x1a/0xa9
[ 112.176009] RIP: 0033:0x7f2055bd5620
[ 112.176009] RSP: 002b:00007ffed2f487d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 112.176009] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2055bd5620
[ 112.176009] RDX: 000000000000000d RSI: 0000000000ee0008 RDI: 0000000000000001
[ 112.176009] RBP: 0000000000000001 R08: 00007f2055e94760 R09: 00007f20564c7b40
[ 112.176009] R10: 0000000000000073 R11: 0000000000000246 R12: 0000000000000000
[ 112.176009] R13: 00007ffed2f48d70 R14: 0000000000000000 R15: 0000000000000000
[ 112.176009] Code: 00 00 00 55 be 02 00 00 00 48 89 e5 e8 62 fb ff ff 5d c3 55 48 89 e5 53 48 89 fb e8 53 e9 ff ff 65 48 8b 14 25 40 c4 00 00 31 c0 <f0> 48 0f b1 13 48 85 c0 74 08 48 89 df e8c6 ff ff ff 5b 5d c3
[ 112.176009] RIP: mutex_lock+0x18/0x30 RSP: ffffc90000b5fc78
[ 112.176009] CR2: 0000000000000260
[ 112.205622] ---[ end trace 76189cd7a9bdd155 ]---

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170317181409.4183-1-krisman@collabora.co.uk
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/bochs/bochs_fbdev.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bochs/bochs_fbdev.c b/drivers/gpu/drm/bochs/bochs_fbdev.c
index e1ec498a6b6e..35f40255644d 100644
--- a/drivers/gpu/drm/bochs/bochs_fbdev.c
+++ b/drivers/gpu/drm/bochs/bochs_fbdev.c
@@ -138,6 +138,7 @@ static int bochsfb_create(struct drm_fb_helper *helper,
info->fix.smem_start = 0;
info->fix.smem_len = size;

+ bochs->fb.initialized = true;
return 0;
}

@@ -155,7 +156,6 @@ static int bochs_fbdev_destroy(struct bochs_device *bochs)
gfb->obj = NULL;
}

- drm_fb_helper_fini(&bochs->fb.helper);
drm_framebuffer_unregister_private(&gfb->base);
drm_framebuffer_cleanup(&gfb->base);

@@ -188,7 +188,6 @@ int bochs_fbdev_init(struct bochs_device *bochs)
if (ret)
goto fini;

- bochs->fb.initialized = true;
return 0;

fini:
@@ -198,9 +197,9 @@ fini:

void bochs_fbdev_fini(struct bochs_device *bochs)
{
- if (!bochs->fb.initialized)
- return;
+ if (bochs->fb.initialized)
+ bochs_fbdev_destroy(bochs);

- bochs_fbdev_destroy(bochs);
+ drm_fb_helper_fini(&bochs->fb.helper);
bochs->fb.initialized = false;
}
--
2.17.1