Re: [REGRESSION] BUG: KFENCE: memory corruption in drm_gem_put_pages+0x186/0x250

From: Oleksandr Natalenko
Date: Mon Oct 02 2023 - 02:20:41 EST


Hello.

On pondělí 2. října 2023 1:45:44 CEST Bagas Sanjaya wrote:
> On Sun, Oct 01, 2023 at 06:32:34PM +0200, Oleksandr Natalenko wrote:
> > Hello.
> >
> > I've got a VM from a cloud provider, and since v6.5 I observe the following kfence splat in dmesg during boot:
> >
> > ```
> > BUG: KFENCE: memory corruption in drm_gem_put_pages+0x186/0x250
> >
> > Corrupted memory at 0x00000000e173a294 [ ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ] (in kfence-#108):
> > drm_gem_put_pages+0x186/0x250
> > drm_gem_shmem_put_pages_locked+0x43/0xc0
> > drm_gem_shmem_object_vunmap+0x83/0xe0
> > drm_gem_vunmap_unlocked+0x46/0xb0
> > drm_fbdev_generic_helper_fb_dirty+0x1dc/0x310
> > drm_fb_helper_damage_work+0x96/0x170
> > process_one_work+0x254/0x470
> > worker_thread+0x55/0x4f0
> > kthread+0xe8/0x120
> > ret_from_fork+0x34/0x50
> > ret_from_fork_asm+0x1b/0x30
> >
> > kfence-#108: 0x00000000cda343af-0x00000000aec2c095, size=3072, cache=kmalloc-4k
> >
> > allocated by task 51 on cpu 0 at 14.668667s:
> > drm_gem_get_pages+0x94/0x2b0
> > drm_gem_shmem_get_pages+0x5d/0x110
> > drm_gem_shmem_object_vmap+0xc4/0x1e0
> > drm_gem_vmap_unlocked+0x3c/0x70
> > drm_client_buffer_vmap+0x23/0x50
> > drm_fbdev_generic_helper_fb_dirty+0xae/0x310
> > drm_fb_helper_damage_work+0x96/0x170
> > process_one_work+0x254/0x470
> > worker_thread+0x55/0x4f0
> > kthread+0xe8/0x120
> > ret_from_fork+0x34/0x50
> > ret_from_fork_asm+0x1b/0x30
> >
> > freed by task 51 on cpu 0 at 14.668697s:
> > drm_gem_put_pages+0x186/0x250
> > drm_gem_shmem_put_pages_locked+0x43/0xc0
> > drm_gem_shmem_object_vunmap+0x83/0xe0
> > drm_gem_vunmap_unlocked+0x46/0xb0
> > drm_fbdev_generic_helper_fb_dirty+0x1dc/0x310
> > drm_fb_helper_damage_work+0x96/0x170
> > process_one_work+0x254/0x470
> > worker_thread+0x55/0x4f0
> > kthread+0xe8/0x120
> > ret_from_fork+0x34/0x50
> > ret_from_fork_asm+0x1b/0x30
> >
> > CPU: 0 PID: 51 Comm: kworker/0:2 Not tainted 6.5.0-pf4 #1 8b557a4173114d86eef7240f7a080080cfc4617e
> > Hardware name: Red Hat KVM, BIOS 1.11.0-2.el7 04/01/2014
> > Workqueue: events drm_fb_helper_damage_work
> > ```
> >
> > This repeats a couple of times and then stops.
> >
> > Currently, I'm running v6.5.5. So far, there's no impact on how VM functions for me.
> >
> > The VGA adapter is as follows: 00:02.0 VGA compatible controller: Cirrus Logic GD 5446
> >
>
> Do you have this issue on v6.4?

No, I did not have this issue with v6.4.

Thanks.

--
Oleksandr Natalenko (post-factum)

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