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| author | Javier Martinez Canillas <javierm@redhat.com> | 2022-05-02 15:50:14 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-12 12:32:40 +0200 |
| commit | 29e515b995a9fc6b00b6d03aee8801ba55798da0 (patch) | |
| tree | 5accdf2aac2ba101ddf5ed275ef6099abe94b220 | |
| parent | 9133dd015a3952dc9b6f2e764c2626c46d0d96f0 (diff) | |
| download | linux-29e515b995a9fc6b00b6d03aee8801ba55798da0.tar.gz linux-29e515b995a9fc6b00b6d03aee8801ba55798da0.tar.bz2 linux-29e515b995a9fc6b00b6d03aee8801ba55798da0.zip | |
fbdev: Make fb_release() return -ENODEV if fbdev was unregistered
[ Upstream commit aafa025c76dcc7d1a8c8f0bdefcbe4eb480b2f6a ]
A reference to the framebuffer device struct fb_info is stored in the file
private data, but this reference could no longer be valid and must not be
accessed directly. Instead, the file_fb_info() accessor function must be
used since it does sanity checking to make sure that the fb_info is valid.
This can happen for example if the registered framebuffer device is for a
driver that just uses a framebuffer provided by the system firmware. In
that case, the fbdev core would unregister the framebuffer device when a
real video driver is probed and ask to remove conflicting framebuffers.
The bug has been present for a long time but commit 27599aacbaef ("fbdev:
Hot-unplug firmware fb devices on forced removal") unmasked it since the
fbdev core started unregistering the framebuffers' devices associated.
Fixes: 27599aacbaef ("fbdev: Hot-unplug firmware fb devices on forced removal")
Reported-by: Maxime Ripard <maxime@cerno.tech>
Reported-by: Junxiao Chang <junxiao.chang@intel.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220502135014.377945-1-javierm@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/video/fbdev/core/fbmem.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 00f0f282e7a1..10a9369c9dea 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1438,7 +1438,10 @@ fb_release(struct inode *inode, struct file *file) __acquires(&info->lock) __releases(&info->lock) { - struct fb_info * const info = file->private_data; + struct fb_info * const info = file_fb_info(file); + + if (!info) + return -ENODEV; lock_fb_info(info); if (info->fbops->fb_release) |