Hi Sudeep,
On Tue, Apr 20, 2021 at 3:53 PM Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
>
> Gentle Ping! There is boot failure because of this issue with linux-next
> on few arm platforms with non PCIe efifb. Please review and get the fix
> merged ASAP so the testing on these platforms can continue with linux-next.
It was merged in drm-tip as d510c88cfbb2 ("efifb: Check efifb_pci_dev
before using it").
Kai-Heng
>
> On Thu, Apr 15, 2021 at 11:22:24AM +0100, Sudeep Holla wrote:
> > Commit a6c0fd3d5a8b ("efifb: Ensure graphics device for efifb stays at PCI D0")
> > added runtime pm calls to probe and remove routines to ensure the PCI
> > device for efifb stays in D0 state. However not ever efifb is based on
> > PCI device and efifb_pci_dev can be NULL if that is the case.
> >
> > In such cases, we will get a boot splat like below due to NULL dereference:
> > -->8
> > Console: switching to colour frame buffer device 240x67
> > fb0: EFI VGA frame buffer device
> > Unable to handle kernel NULL pointer dereference at virtual address 0000000000000270
> > Mem abort info:
> > ESR = 0x96000004
> > EC = 0x25: DABT (current EL), IL = 32 bits
> > SET = 0, FnV = 0
> > EA = 0, S1PTW = 0
> > Data abort info:
> > ISV = 0, ISS = 0x00000004
> > CM = 0, WnR = 0
> > [0000000000000270] user address but active_mm is swapper
> > Internal error: Oops: 96000004 [#1] PREEMPT SMP
> > Modules linked in:
> > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc7-next-20210413 #1
> > Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform
> > pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)
> > pc : pm_runtime_drop_link+0x12c/0x338
> > lr : efifb_probe+0x7bc/0x7f0
> > Call trace:
> > pm_runtime_drop_link+0x12c/0x338
> > efifb_probe+0x7bc/0x7f0
> > platform_probe+0x68/0xd8
> > really_probe+0xe4/0x3a8
> > driver_probe_device+0x64/0xc8
> > device_driver_attach+0x74/0x80
> > __driver_attach+0x64/0xf0
> > bus_for_each_dev+0x70/0xc0
> > driver_attach+0x24/0x30
> > bus_add_driver+0x150/0x1f8
> > driver_register+0x64/0x120
> > __platform_driver_register+0x28/0x38
> > efifb_driver_init+0x1c/0x28
> > do_one_initcall+0x48/0x2b0
> > kernel_init_freeable+0x1e8/0x258
> > kernel_init+0x14/0x118
> > ret_from_fork+0x10/0x30
> > Code: 88027c01 35ffffa2 17fff706 f9800051 (885f7c40)
> > ---[ end trace 17d8da630bf8ff77 ]---
> > Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
> > -->8
> >
> > Fix the issue by checking for non-NULL efifb_pci_dev before dereferencing
> > for runtime pm calls in probe and remove routines.
> >
> > Fixes: a6c0fd3d5a8b ("efifb: Ensure graphics device for efifb stays at PCI D0")
> > Cc: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> > Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> > Cc: Peter Jones <pjones@xxxxxxxxxx>
> > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> > ---
> > drivers/video/fbdev/efifb.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
> > index f58a545b3bf3..8ea8f079cde2 100644
> > --- a/drivers/video/fbdev/efifb.c
> > +++ b/drivers/video/fbdev/efifb.c
> > @@ -575,7 +575,8 @@ static int efifb_probe(struct platform_device *dev)
> > goto err_fb_dealoc;
> > }
> > fb_info(info, "%s frame buffer device\n", info->fix.id);
> > - pm_runtime_get_sync(&efifb_pci_dev->dev);
> > + if (efifb_pci_dev)
> > + pm_runtime_get_sync(&efifb_pci_dev->dev);
> > return 0;
> >
> > err_fb_dealoc:
> > @@ -602,7 +603,8 @@ static int efifb_remove(struct platform_device *pdev)
> > unregister_framebuffer(info);
> > sysfs_remove_groups(&pdev->dev.kobj, efifb_groups);
> > framebuffer_release(info);
> > - pm_runtime_put(&efifb_pci_dev->dev);
> > + if (efifb_pci_dev)
> > + pm_runtime_put(&efifb_pci_dev->dev);
> >
> > return 0;
> > }
> > --
> > 2.25.1
> >
>
> --
> Regards,
> Sudeep
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