1. 21 5月, 2020 1 次提交
    • C
      drm: Restore the NULL check for drm_gem_object_put() · 0e799e84
      Chris Wilson 提交于
      Some users want to pass NULL to drm_gem_object_put(), but those using
      __drm_gem_object_put() did not. Compromise, have both and let the
      compiler sort it out.
      
      drm_gem_fb_destroy() calls drm_gem_object_put() with NULL obj causing:
      [   11.584209] BUG: kernel NULL pointer dereference, address: 0000000000000000
      [   11.584213] #PF: supervisor write access in kernel mode
      [   11.584215] #PF: error_code(0x0002) - not-present page
      [   11.584216] PGD 0 P4D 0
      [   11.584220] Oops: 0002 [#1] SMP NOPTI
      [   11.584223] CPU: 7 PID: 1571 Comm: gnome-shell Tainted: G            E     5.7.0-rc1-1-default+ #27
      [   11.584225] Hardware name: Micro-Star International Co., Ltd. MS-7A31/X370 XPOWER GAMING TITANIUM (MS-7A31), BIOS 1.MR 12/03/2019
      [   11.584237] RIP: 0010:drm_gem_fb_destroy+0x28/0x70 [drm_kms_helper]
      <snip>
      [   11.584256] Call Trace:
      [   11.584279]  drm_mode_rmfb+0x189/0x1c0 [drm]
      [   11.584299]  ? drm_mode_rmfb+0x1c0/0x1c0 [drm]
      [   11.584314]  drm_ioctl_kernel+0xaa/0xf0 [drm]
      [   11.584329]  drm_ioctl+0x1ff/0x3b0 [drm]
      [   11.584347]  ? drm_mode_rmfb+0x1c0/0x1c0 [drm]
      [   11.584421]  amdgpu_drm_ioctl+0x49/0x80 [amdgpu]
      [   11.584427]  ksys_ioctl+0x87/0xc0
      [   11.584430]  __x64_sys_ioctl+0x16/0x20
      [   11.584434]  do_syscall_64+0x5f/0x240
      [   11.584438]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
      [   11.584440] RIP: 0033:0x7f0ef80f7227
      Reported-by: NNirmoy Das <nirmoy.das@amd.com>
      Fixes: b5d25074 ("drm/gem: fold drm_gem_object_put_unlocked and __drm_gem_object_put()")
      Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
      Cc: Nirmoy Das <nirmoy.das@amd.com>
      Cc: Emil Velikov <emil.velikov@collabora.com>
      Cc: Christian König <christian.koenig@amd.com>.
      Acked-by: NNirmoy Das <nirmoy.das@amd.com>
      Reviewed-by: NEmil Velikov <emil.velikov@collabora.com>
      Link: https://patchwork.freedesktop.org/patch/msgid/20200520142347.29060-1-chris@chris-wilson.co.uk
      0e799e84
  2. 20 5月, 2020 39 次提交