<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <meta content="text/html; charset=utf-8"> </head> <body bgcolor="#FFFFFF"> <div dir="auto">No, the problem is the function pointer analysis. <div dir="auto"><br> </div> <div dir="auto">In other words the KIQ ring is sometimes used in atomic and even interrupt context.</div> <div dir="auto"><br> </div> <div dir="auto">But the UVD ring is never used in atomic context.</div> <div dir="auto"><br> </div> <div dir="auto">But I don't see a way a static analysis could ever figure that out.</div> <div dir="auto"><br> </div> <div dir="auto">Regards,</div> <div dir="auto">Christian.</div> </div> <div class="gmail_extra"><br> <div class="gmail_quote">Am 15.09.2018 11:18 schrieb Jia-Ju Bai <baijiaju1990@gmail.com>:<br type="attribution"> </div> </div> <div>Sorry, I am still not clear why the call chain I proposed is incorrect...<br> <br> I find a conditional in amdgpu_mm_wreg():<br> <br> if (!(acc_flags & AMDGPU_REGS_NO_KIQ) && amdgpu_sriov_runtime(adev))<br> return amdgpu_virt_kiq_wreg(adev, reg, v);<br> <br> Is amdgpu_virt_kiq_wreg() never called from WREG32() or RREG32()?<br> <br> <br> Best wishes,<br> Jia-Ju Bai<br> <br> <br> <div class="moz-cite-prefix">On 2018/9/15 17:10, Koenig, Christian wrote:<br> </div> <blockquote type="cite"> <div dir="auto"> <div>amdgpu_ring_alloc() does call amdgpu_uvd_begin_use(), but never in the call chain you proposed.</div> <div dir="auto"><br> </div> <div dir="auto">Thinking about it I actually don't see a way a statically analysis could ever figure that out.</div> <div dir="auto"><br> </div> <div dir="auto">Christian.</div> <div dir="auto"> <div class="gmail_extra" dir="auto"><br> <div class="gmail_quote">Am 15.09.2018 11:05 schrieb Jia-Ju Bai <a class="moz-txt-link-rfc2396E" href="mailto:baijiaju1990@gmail.com"> <baijiaju1990@gmail.com></a>:<br type="attribution"> <blockquote class="quote" style="margin:0 0 0 .8ex; border-left:1px #ccc solid; padding-left:1ex"> <div>Thanks for your reply.<br> <br> <div>On 2018/9/15 17:01, Koenig, Christian wrote:<br> </div> <blockquote> <div> <div dir="auto">Sorry to say that but your analysis tool is buggy. <div dir="auto"><br> </div> <div dir="auto">The proposed call paths will never trigger.</div> </div> </div> </blockquote> <br> Could you please explain which piece of the call path is incorrect?<br> I am not very sure of my function pointer analysis.<br> Does amdgpu_ring_alloc() never calls amdgpu_uvd_ring_begin_use()?<br> <br> Thanks in advance.<br> <br> <br> Best wishes,<br> Jia-Ju Bai<br> <br> <blockquote> <div> <div dir="auto"> <div dir="auto"><br> </div> <div dir="auto">Regards,</div> <div dir="auto">Christian.</div> </div> <div><br> <div>Am 15.09.2018 10:59 schrieb Jia-Ju Bai <a href="mailto:baijiaju1990@gmail.com"> <baijiaju1990@gmail.com></a>:<br type="attribution"> </div> </div> </div> <font size="2"><span style="font-size:11pt"> <div>The driver may sleep with holding a spinlock.<br> The function call paths (from bottom to top) in Linux-4.17 are:<br> <br> [FUNC] mutex_lock_nested<br> drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c, 1477:<br> mutex_lock_nested in amdgpu_dpm_enable_uvd<br> drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c, 1154:<br> amdgpu_dpm_enable_uvd in amdgpu_uvd_ring_begin_use<br> drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, 80:<br> [FUNC_PTR]amdgpu_uvd_ring_begin_use in amdgpu_ring_alloc<br> drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, 199:<br> amdgpu_ring_alloc in amdgpu_virt_kiq_wreg<br> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c, 207:<br> amdgpu_virt_kiq_wreg in amdgpu_mm_wreg<br> drivers/gpu/drm/amd/amdgpu/vi.c, 207:<br> amdgpu_mm_wreg in vi_gc_cac_rreg<br> drivers/gpu/drm/amd/amdgpu/vi.c, 206:<br> _raw_spin_lock_irqsave in vi_gc_cac_rreg<br> <br> [FUNC] mutex_lock_nested<br> drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c, 1477:<br> mutex_lock_nested in amdgpu_dpm_enable_uvd<br> drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c, 1154:<br> amdgpu_dpm_enable_uvd in amdgpu_uvd_ring_begin_use<br> drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, 80:<br> [FUNC_PTR]amdgpu_uvd_ring_begin_use in amdgpu_ring_alloc<br> drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, 199:<br> amdgpu_ring_alloc in amdgpu_virt_kiq_wreg<br> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c, 207:<br> amdgpu_virt_kiq_wreg in amdgpu_mm_wreg<br> drivers/gpu/drm/amd/amdgpu/soc15.c, 106:<br> amdgpu_mm_wreg in soc15_pcie_rreg<br> drivers/gpu/drm/amd/amdgpu/soc15.c, 105:<br> _raw_spin_lock_irqsave in soc15_pcie_rreg<br> <br> [FUNC] mutex_lock_nested<br> drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c, 1477:<br> mutex_lock_nested in amdgpu_dpm_enable_uvd<br> drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c, 1154:<br> amdgpu_dpm_enable_uvd in amdgpu_uvd_ring_begin_use<br> drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, 80:<br> [FUNC_PTR]amdgpu_uvd_ring_begin_use in amdgpu_ring_alloc<br> drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, 199:<br> amdgpu_ring_alloc in amdgpu_virt_kiq_wreg<br> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c, 207:<br> amdgpu_virt_kiq_wreg in amdgpu_mm_wreg<br> drivers/gpu/drm/amd/amdgpu/cik.c, 139:<br> amdgpu_mm_wreg in cik_uvd_ctx_wreg<br> drivers/gpu/drm/amd/amdgpu/cik.c, 138:<br> _raw_spin_lock_irqsave in cik_uvd_ctx_wreg<br> <br> [FUNC] mutex_lock_nested<br> drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c, 1477:<br> mutex_lock_nested in amdgpu_dpm_enable_uvd<br> drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c, 1154:<br> amdgpu_dpm_enable_uvd in amdgpu_uvd_ring_begin_use<br> drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c, 80:<br> [FUNC_PTR]amdgpu_uvd_ring_begin_use in amdgpu_ring_alloc<br> drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, 199:<br> amdgpu_ring_alloc in amdgpu_virt_kiq_wreg<br> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c, 207:<br> amdgpu_virt_kiq_wreg in amdgpu_mm_wreg<br> drivers/gpu/drm/amd/amdgpu/dce_v6_0.c, 126:<br> amdgpu_mm_wreg in dce_v6_0_audio_endpt_rreg<br> drivers/gpu/drm/amd/amdgpu/dce_v6_0.c, 125:<br> _raw_spin_lock_irqsave in dce_v6_0_audio_endpt_rreg<br> <br> Note that [FUNC_PTR] means a function pointer call is used.<br> <br> These bugs are found by my static analysis tool DSAC.<br> <br> <br> Best wishes,<br> Jia-Ju Bai<br> </div> </span></font></blockquote> <br> </div> </blockquote> </div> <br> </div> </div> </div> </blockquote> <br> </div> </body> </html>