On Tue, Mar 12, 2024 at 5:36 AM Jocelyn Falempe <jfalempe@xxxxxxxxxx> wrote:
>
> The driver creates /sys/kernel/debug/dri/0/mob_ttm even when the
> corresponding ttm_resource_manager is not allocated.
> This leads to a crash when trying to read from this file.
>
> Add a check to create mob_ttm, system_mob_ttm, and gmr_ttm debug file
> only when the corresponding ttm_resource_manager is allocated.
>
> crash> bt
> PID: 3133409 TASK: ffff8fe4834a5000 CPU: 3 COMMAND: "grep"
> #0 [ffffb954506b3b20] machine_kexec at ffffffffb2a6bec3
> #1 [ffffb954506b3b78] __crash_kexec at ffffffffb2bb598a
> #2 [ffffb954506b3c38] crash_kexec at ffffffffb2bb68c1
> #3 [ffffb954506b3c50] oops_end at ffffffffb2a2a9b1
> #4 [ffffb954506b3c70] no_context at ffffffffb2a7e913
> #5 [ffffb954506b3cc8] __bad_area_nosemaphore at ffffffffb2a7ec8c
> #6 [ffffb954506b3d10] do_page_fault at ffffffffb2a7f887
> #7 [ffffb954506b3d40] page_fault at ffffffffb360116e
> [exception RIP: ttm_resource_manager_debug+0x11]
> RIP: ffffffffc04afd11 RSP: ffffb954506b3df0 RFLAGS: 00010246
> RAX: ffff8fe41a6d1200 RBX: 0000000000000000 RCX: 0000000000000940
> RDX: 0000000000000000 RSI: ffffffffc04b4338 RDI: 0000000000000000
> RBP: ffffb954506b3e08 R8: ffff8fee3ffad000 R9: 0000000000000000
> R10: ffff8fe41a76a000 R11: 0000000000000001 R12: 00000000ffffffff
> R13: 0000000000000001 R14: ffff8fe5bb6f3900 R15: ffff8fe41a6d1200
> ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
> #8 [ffffb954506b3e00] ttm_resource_manager_show at ffffffffc04afde7 [ttm]
> #9 [ffffb954506b3e30] seq_read at ffffffffb2d8f9f3
> RIP: 00007f4c4eda8985 RSP: 00007ffdbba9e9f8 RFLAGS: 00000246
> RAX: ffffffffffffffda RBX: 000000000037e000 RCX: 00007f4c4eda8985
> RDX: 000000000037e000 RSI: 00007f4c41573000 RDI: 0000000000000003
> RBP: 000000000037e000 R8: 0000000000000000 R9: 000000000037fe30
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4c41573000
> R13: 0000000000000003 R14: 00007f4c41572010 R15: 0000000000000003
> ORIG_RAX: 0000000000000000 CS: 0033 SS: 002b
>
> Signed-off-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
> Fixes: af4a25bbe5e7 ("drm/vmwgfx: Add debugfs entries for various ttm resource managers")
> Cc: <stable@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> index d3e308fdfd5b..c7d90f96d16a 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> @@ -1444,12 +1444,15 @@ static void vmw_debugfs_resource_managers_init(struct vmw_private *vmw)
> root, "system_ttm");
> ttm_resource_manager_create_debugfs(ttm_manager_type(&vmw->bdev, TTM_PL_VRAM),
> root, "vram_ttm");
> - ttm_resource_manager_create_debugfs(ttm_manager_type(&vmw->bdev, VMW_PL_GMR),
> - root, "gmr_ttm");
> - ttm_resource_manager_create_debugfs(ttm_manager_type(&vmw->bdev, VMW_PL_MOB),
> - root, "mob_ttm");
> - ttm_resource_manager_create_debugfs(ttm_manager_type(&vmw->bdev, VMW_PL_SYSTEM),
> - root, "system_mob_ttm");
> + if (vmw->has_gmr)
> + ttm_resource_manager_create_debugfs(ttm_manager_type(&vmw->bdev, VMW_PL_GMR),
> + root, "gmr_ttm");
> + if (vmw->has_mob) {
> + ttm_resource_manager_create_debugfs(ttm_manager_type(&vmw->bdev, VMW_PL_MOB),
> + root, "mob_ttm");
> + ttm_resource_manager_create_debugfs(ttm_manager_type(&vmw->bdev, VMW_PL_SYSTEM),
> + root, "system_mob_ttm");
> + }
> }
>
> static int vmwgfx_pm_notifier(struct notifier_block *nb, unsigned long val,
>
> base-commit: b33651a5c98dbd5a919219d8c129d0674ef74299
> --
> 2.44.0
>
Thanks! That looks great. I can push it through drm-misc-fixes.
Reviewed-by: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
z
