On Tue, Mar 12, 2024 at 5:36 AM Jocelyn Falempe jfalempe@redhat.com 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@redhat.com Fixes: af4a25bbe5e7 ("drm/vmwgfx: Add debugfs entries for various ttm resource managers") Cc: stable@vger.kernel.org

---

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@broadcom.com

z