[PATCH] drm/msm: dpu: Allocate proper amount for dpu_crtc_state

Tue Dec 4 15:51:42 UTC 2018

On Mon, Dec 3, 2018 at 2:56 PM Sean Paul <sean at poorly.run> wrote:
>
> From: Sean Paul <seanpaul at chromium.org>
>
> Since dpu_crtc subclasses crtc_state, we need a custom .reset hook in
> order to allocate the right amount of memory to accommodate the
> additional struct members in dpu_crtc_state. So bring it [partially]
> back.
>
> Relevant KASAN splat:
> [   10.333382] ==================================================================
> [   10.344288] BUG: KASAN: slab-out-of-bounds in kmemdup+0x50/0x80
> [   10.350390] Read of size 736 at addr ffffffc0d9f06080 by task frecon/394
>
> [   10.358861] CPU: 6 PID: 394 Comm: frecon Tainted: G        W         4.19.4 #121
> [   10.366476] Hardware name: Google Cheza (rev2) (DT)
> [   10.371514] Call trace:
> [   10.374087]  dump_backtrace+0x0/0x194
> [   10.377878]  show_stack+0x20/0x28
> [   10.381330]  dump_stack+0xa0/0xc8
> [   10.384783]  print_address_description+0x78/0x2e0
> [   10.389639]  kasan_report+0x290/0x2d0
> [   10.393428]  check_memory_region+0x20/0x14c
> [   10.397740]  __asan_loadN+0x14/0x1c
> [   10.401345]  kmemdup+0x50/0x80
> [   10.404524]  dpu_crtc_duplicate_state+0x58/0xa0
> [   10.409228]  drm_atomic_get_crtc_state+0xac/0x178
> [   10.414095]  __drm_atomic_helper_set_config+0x54/0x4a4
> [   10.419393]  drm_atomic_helper_set_config+0x60/0xb4
> [   10.424435]  drm_mode_setcrtc+0x720/0x760
> [   10.428570]  drm_ioctl_kernel+0xd8/0x13c
> [   10.432617]  drm_ioctl+0x380/0x4f4
> [   10.436150]  drm_compat_ioctl+0x54/0x13c
> [   10.440219]  __arm64_compat_sys_ioctl+0x1d8/0xef4
> [   10.445086]  el0_svc_common+0xd8/0x138
> [   10.448961]  el0_svc_compat_handler+0x58/0x68
> [   10.453463]  el0_svc_compat+0x8/0x18
>
> [   10.458712] Allocated by task 56:
> [   10.462148]  kasan_kmalloc.part.4+0x48/0xf4
> [   10.466465]  kasan_kmalloc+0x8c/0xa0
> [   10.470165]  kmem_cache_alloc_trace+0x25c/0x27c
> [   10.474848]  drm_atomic_helper_crtc_reset+0x68/0x98
> [   10.479877]  drm_mode_config_reset+0xc4/0x19c
> [   10.484383]  msm_drm_bind+0x814/0x8dc
> [   10.488169]  try_to_bring_up_master.part.7+0x48/0xac
> [   10.493282]  component_master_add_with_match+0x158/0x198
> [   10.498758]  msm_pdev_probe+0x328/0x348
> [   10.502736]  platform_drv_probe+0x74/0xc8
> [   10.506877]  really_probe+0x1ac/0x35c
> [   10.510659]  driver_probe_device+0xd4/0x118
> [   10.514975]  __device_attach_driver+0xc8/0xf4
> [   10.519477]  bus_for_each_drv+0xb4/0xe4
> [   10.523439]  __device_attach+0xd0/0x158
> [   10.527394]  device_initial_probe+0x24/0x30
> [   10.531715]  bus_probe_device+0x50/0xe4
> [   10.535681]  deferred_probe_work_func+0xac/0xdc
> [   10.540376]  process_one_work+0x3f0/0x6d4
> [   10.544521]  worker_thread+0x3f4/0x520
> [   10.548399]  kthread+0x1b4/0x1c8
> [   10.551740]  ret_from_fork+0x10/0x18
>
> [   10.556986] Freed by task 0:
> [   10.559967] (stack is not available)
>
> [   10.565216] The buggy address belongs to the object at ffffffc0d9f06080
>                 which belongs to the cache kmalloc-1024 of size 1024
> [   10.578268] The buggy address is located 0 bytes inside of
>                 1024-byte region [ffffffc0d9f06080, ffffffc0d9f06480)
> [   10.590248] The buggy address belongs to the page:
> [   10.595195] page:ffffffbf0367c000 count:1 mapcount:0 mapping:ffffffc0de40f680 index:0x0 compound_mapcount: 0
> [   10.605321] flags: 0x4000000000008100(slab|head)
> [   10.610100] raw: 4000000000008100 ffffffbf0369fa08 ffffffbf0367f008 ffffffc0de40f680
> [   10.618077] raw: 0000000000000000 0000000000150015 00000001ffffffff 0000000000000000
> [   10.626049] page dumped because: kasan: bad access detected
>
> [   10.633341] Memory state around the buggy address:
> [   10.638282]  ffffffc0d9f06180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [   10.645710]  ffffffc0d9f06200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [   10.653139] >ffffffc0d9f06280: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
> [   10.660571]                                         ^
> [   10.665774]  ffffffc0d9f06300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [   10.673210]  ffffffc0d9f06380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [   10.680639] ==================================================================
>
> Fixes: a6ba45afda41 ("drm/msm/dpu: Replace dpu_crtc_reset by atomic helper")
> Cc: Sean Paul <seanpaul at chromium.org>
> Cc: Bruce Wang <bzwang at chromium.org>
> Cc: Rob Clark <robdclark at gmail.com>
> Signed-off-by: Sean Paul <seanpaul at chromium.org>

Reviewed-by: Bruce Wang <bzwang at chromium.org>

> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 1e3e57817b72b..d27ea2a95f85b 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -819,6 +819,18 @@ static void _dpu_crtc_vblank_enable_no_lock(
>         }
>  }
>
> +static void dpu_crtc_reset(struct drm_crtc *crtc)
> +{
> +       struct dpu_crtc_state *cstate;
> +
> +       if (crtc->state)
> +               dpu_crtc_destroy_state(crtc, crtc->state);
> +
> +       crtc->state = kzalloc(sizeof(*cstate), GFP_KERNEL);
> +       if (crtc->state)
> +               crtc->state->crtc = crtc;
> +}
> +
>  /**
>   * dpu_crtc_duplicate_state - state duplicate hook
>   * @crtc: Pointer to drm crtc structure
> @@ -1466,7 +1478,7 @@ static const struct drm_crtc_funcs dpu_crtc_funcs = {
>         .set_config = drm_atomic_helper_set_config,
>         .destroy = dpu_crtc_destroy,
>         .page_flip = drm_atomic_helper_page_flip,
> -       .reset = drm_atomic_helper_crtc_reset,
> +       .reset = dpu_crtc_reset,
>         .atomic_duplicate_state = dpu_crtc_duplicate_state,
>         .atomic_destroy_state = dpu_crtc_destroy_state,
>         .late_register = dpu_crtc_late_register,
> --
> Sean Paul, Software Engineer, Google / Chromium OS
>