| Message ID | 20220210065824.368355-1-zhouzhouyi@gmail.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | [linux-next] video: fbdev: fbmem: fix pointer reference to null device field | expand |
On Thu, Feb 10, 2022 at 02:58:24PM +0800, Zhouyi Zhou wrote: > In function do_remove_conflicting_framebuffers, if device is NULL, there > will be null pointer reference. The patch add a check to the if expression. > > Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> > --- > Dear Linux folks > > I discover this bug in the PowerPC VM provided by > Open source lab of Oregon State University: > > https://lkml.org/lkml/2022/2/8/1145 > > I found that the root cause of null device field is in offb_init_fb: > info = framebuffer_alloc(sizeof(u32) * 16, NULL); > > I have tested the patch in the PowerPC VM. Hope my patch can be correct. This looks plausible to me, but I am quite unfamiliar with this code. Thanx, Paul > Many Thanks > Zhouyi > -- > drivers/video/fbdev/core/fbmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c > index 34d6bb1bf82e..422b1fc01722 100644 > --- a/drivers/video/fbdev/core/fbmem.c > +++ b/drivers/video/fbdev/core/fbmem.c > @@ -1579,7 +1579,7 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a, > * If it's not a platform device, at least print a warning. A > * fix would add code to remove the device from the system. > */ > - if (dev_is_platform(device)) { > + if (device && dev_is_platform(device)) { > registered_fb[i]->forced_out = true; > platform_device_unregister(to_platform_device(device)); > } else { > -- > 2.25.1 >
Dear Zhouyi, Am 10.02.22 um 07:58 schrieb Zhouyi Zhou: > In function do_remove_conflicting_framebuffers, if device is NULL, there > will be null pointer reference. The patch add a check to the if expression. > > Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> > --- > Dear Linux folks > > I discover this bug in the PowerPC VM provided by > Open source lab of Oregon State University: > > https://lkml.org/lkml/2022/2/8/1145 > > I found that the root cause of null device field is in offb_init_fb: > info = framebuffer_alloc(sizeof(u32) * 16, NULL); > > I have tested the patch in the PowerPC VM. Hope my patch can be correct. > > Many Thanks > Zhouyi > -- > drivers/video/fbdev/core/fbmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c > index 34d6bb1bf82e..422b1fc01722 100644 > --- a/drivers/video/fbdev/core/fbmem.c > +++ b/drivers/video/fbdev/core/fbmem.c > @@ -1579,7 +1579,7 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a, > * If it's not a platform device, at least print a warning. A > * fix would add code to remove the device from the system. > */ > - if (dev_is_platform(device)) { > + if (device && dev_is_platform(device)) { > registered_fb[i]->forced_out = true; > platform_device_unregister(to_platform_device(device)); > } else { Looks reasonable. Acked-by: Paul Menzel <pmenzel@molgen.mpg.de> Kind regards, Paul PS: Please note, this should be unrelated to my problem though, as I didn’t use linux-next. (Let’s continue in the other thread though.)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 34d6bb1bf82e..422b1fc01722 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1579,7 +1579,7 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a, * If it's not a platform device, at least print a warning. A * fix would add code to remove the device from the system. */ - if (dev_is_platform(device)) { + if (device && dev_is_platform(device)) { registered_fb[i]->forced_out = true; platform_device_unregister(to_platform_device(device)); } else {
In function do_remove_conflicting_framebuffers, if device is NULL, there will be null pointer reference. The patch add a check to the if expression. Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> --- Dear Linux folks I discover this bug in the PowerPC VM provided by Open source lab of Oregon State University: https://lkml.org/lkml/2022/2/8/1145 I found that the root cause of null device field is in offb_init_fb: info = framebuffer_alloc(sizeof(u32) * 16, NULL); I have tested the patch in the PowerPC VM. Hope my patch can be correct. Many Thanks Zhouyi -- drivers/video/fbdev/core/fbmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)