Hi, > -----Original Message----- > From: Intel-gfx <intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Linux > regression tracking (Thorsten Leemhuis) > Sent: Monday, 11 March 2024 17.53 > To: Deak, Imre <imre.deak@xxxxxxxxx> > Cc: regressions@xxxxxxxxxxxxxxx; Chris Bainbridge > <chris.bainbridge@xxxxxxxxx>; intel-gfx <intel-gfx@xxxxxxxxxxxxxxxxxxxxx>; > David Airlie <airlied@xxxxxxxx>; Daniel Vetter <daniel@xxxxxxxx>; ML dri-devel > <dri-devel@xxxxxxxxxxxxxxxxxxxxx> > Subject: Re: [REGRESSION] Divide-by-zero on DisplayPort MST unplug with > nouveau > > On 07.03.24 18:58, Chris Bainbridge wrote: > > ----- Forwarded message from Chris Bainbridge > > <chris.bainbridge@xxxxxxxxx> ----- > > > > Date: Sat, 10 Feb 2024 21:24:59 +0000 > > Hmm, it looks like nobody is looking into this regression. Is there a good > reason? > > Imre, or did you maybe just miss that Chris' regression seems to be caused by > a commit of yours? He initally proposed a fix (the forwarded mail that is > quoted here) more a month ago already here: > https://lore.kernel.org/all/ZcfpqwnkSoiJxeT9@debian.local/ > > Chris recently filed a ticket, too: > https://gitlab.freedesktop.org/drm/misc/kernel/-/issues/36 Please file https://drm.pages.freedesktop.org/intel-docs/how-to-file-i915-bugs.html > > Mostly silence there as well. :-/ > > Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) > > P.S: Chris, sorry, I had missed that you initially proposed the fix a month ago; if > I had noticed this earlier I had sent a mail like this one earlier. > -- > Everything you wanna know about Linux kernel regression tracking: > https://linux-regtracking.leemhuis.info/about/#tldr > If I did something stupid, please tell me, as explained on that page. > > > From: Chris Bainbridge <chris.bainbridge@xxxxxxxxx> > > To: dri-devel@xxxxxxxxxxxxxxxxxxxxx > > Cc: lyude@xxxxxxxxxx, ville.syrjala@xxxxxxxxxxxxxxx, > stanislav.lisovskiy@xxxxxxxxx, > > mripard@xxxxxxxxxx, imre.deak@xxxxxxxxx > > Subject: [PATCH] Fix divide-by-zero on DP unplug with nouveau > > > > The following trace occurs when using nouveau and unplugging a DP MST > > adaptor: > >> divide error: 0000 [#1] PREEMPT SMP PTI > > CPU: 7 PID: 2962 Comm: Xorg Not tainted 6.8.0-rc3+ #744 Hardware > > name: Razer Blade/DANA_MB, BIOS 01.01 08/31/2018 > > RIP: 0010:drm_dp_bw_overhead+0xb4/0x110 [drm_display_helper] > > Code: c6 b8 01 00 00 00 75 61 01 c6 41 0f af f3 41 0f af f1 c1 e1 04 > > 48 63 c7 31 d2 89 ff 48 8b 5d f8 c9 48 0f af f1 48 8d 44 06 ff <48> f7 > > f7 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 45 31 d2 45 31 > > RSP: 0018:ffffb2c5c211fa30 EFLAGS: 00010206 > > RAX: ffffffffffffffff RBX: 0000000000000000 RCX: 0000000000f59b00 > > RDX: 0000000000000000 RSI: 0000000000000000 RDI: > 0000000000000000 > > RBP: ffffb2c5c211fa48 R08: 0000000000000001 R09: > 0000000000000020 > > R10: 0000000000000004 R11: 0000000000000000 R12: > 0000000000023b4a > > R13: ffff91d37d165800 R14: ffff91d36fac6d80 R15: ffff91d34a764010 > > FS: 00007f4a1ca3fa80(0000) GS:ffff91d6edbc0000(0000) > > knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000559491d49000 CR3: 000000011d180002 CR4: > 00000000003706f0 > > Call Trace: > > <TASK> > > ? show_regs+0x6d/0x80 > > ? die+0x37/0xa0 > > ? do_trap+0xd4/0xf0 > > ? do_error_trap+0x71/0xb0 > > ? drm_dp_bw_overhead+0xb4/0x110 [drm_display_helper] > > ? exc_divide_error+0x3a/0x70 > > ? drm_dp_bw_overhead+0xb4/0x110 [drm_display_helper] > > ? asm_exc_divide_error+0x1b/0x20 > > ? drm_dp_bw_overhead+0xb4/0x110 [drm_display_helper] > > ? drm_dp_calc_pbn_mode+0x2e/0x70 [drm_display_helper] > > nv50_msto_atomic_check+0xda/0x120 [nouveau] > > drm_atomic_helper_check_modeset+0xa87/0xdf0 [drm_kms_helper] > > drm_atomic_helper_check+0x19/0xa0 [drm_kms_helper] > > nv50_disp_atomic_check+0x13f/0x2f0 [nouveau] > > drm_atomic_check_only+0x668/0xb20 [drm] > > ? drm_connector_list_iter_next+0x86/0xc0 [drm] > > drm_atomic_commit+0x58/0xd0 [drm] > > ? __pfx___drm_printfn_info+0x10/0x10 [drm] > > drm_atomic_connector_commit_dpms+0xd7/0x100 [drm] > > drm_mode_obj_set_property_ioctl+0x1c5/0x450 [drm] > > ? __pfx_drm_connector_property_set_ioctl+0x10/0x10 [drm] > > drm_connector_property_set_ioctl+0x3b/0x60 [drm] > > drm_ioctl_kernel+0xb9/0x120 [drm] > > drm_ioctl+0x2d0/0x550 [drm] > > ? __pfx_drm_connector_property_set_ioctl+0x10/0x10 [drm] > > nouveau_drm_ioctl+0x61/0xc0 [nouveau] > > __x64_sys_ioctl+0xa0/0xf0 > > do_syscall_64+0x76/0x140 > > ? do_syscall_64+0x85/0x140 > > ? do_syscall_64+0x85/0x140 > > entry_SYSCALL_64_after_hwframe+0x6e/0x76 > > RIP: 0033:0x7f4a1cd1a94f > > Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 > > 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <41> 89 > > c0 3d 00 f0 ff ff 77 1f 48 8b 44 24 18 64 48 2b 04 25 28 00 > > RSP: 002b:00007ffd2f1df520 EFLAGS: 00000246 ORIG_RAX: > > 0000000000000010 > > RAX: ffffffffffffffda RBX: 00007ffd2f1df5b0 RCX: 00007f4a1cd1a94f > > RDX: 00007ffd2f1df5b0 RSI: 00000000c01064ab RDI: 000000000000000f > > RBP: 00000000c01064ab R08: 000056347932deb8 R09: > 000056347a7d99c0 > > R10: 0000000000000000 R11: 0000000000000246 R12: > 000056347938a220 > > R13: 000000000000000f R14: 0000563479d9f3f0 R15: > 0000000000000000 > > </TASK> > > Modules linked in: rfcomm xt_conntrack nft_chain_nat xt_MASQUERADE > nf_nat nf_conntrack_netlink nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 > xfrm_user xfrm_algo xt_addrtype nft_compat nf_tables nfnetlink br_netfilter > bridge stp llc ccm cmac algif_hash overlay algif_skcipher af_alg bnep > binfmt_misc snd_sof_pci_intel_cnl snd_sof_intel_hda_common > snd_soc_hdac_hda snd_sof_pci snd_sof_xtensa_dsp snd_sof_intel_hda > snd_sof snd_sof_utils snd_soc_acpi_intel_match snd_soc_acpi snd_soc_core > snd_compress snd_sof_intel_hda_mlink snd_hda_ext_core iwlmvm > intel_rapl_msr intel_rapl_common intel_tcc_cooling x86_pkg_temp_thermal > intel_powerclamp mac80211 coretemp kvm_intel snd_hda_codec_hdmi kvm > snd_hda_codec_realtek snd_hda_codec_generic uvcvideo libarc4 > snd_hda_intel snd_intel_dspcfg snd_hda_codec iwlwifi videobuf2_vmalloc > videobuf2_memops uvc irqbypass btusb videobuf2_v4l2 snd_seq_midi > crct10dif_pclmul hid_multitouch crc32_pclmul snd_seq_midi_event btrtl > snd_hwdep videodev polyval_clmulni polyval_generic snd_rawmidi > > ghash_clmulni_intel aesni_intel btintel crypto_simd snd_hda_core > > cryptd snd_seq btbcm ee1004 8250_dw videobuf2_common btmtk rapl > > nls_iso8859_1 mei_hdcp thunderbolt bluetooth intel_cstate wmi_bmof > > intel_wmi_thunderbolt cfg80211 snd_pcm mc snd_seq_device i2c_i801 > > r8169 ecdh_generic snd_timer i2c_smbus ecc snd mei_me intel_lpss_pci > > mei ahci intel_lpss soundcore realtek libahci idma64 intel_pch_thermal > > i2c_hid_acpi i2c_hid acpi_pad sch_fq_codel msr parport_pc ppdev lp > > parport efi_pstore ip_tables x_tables autofs4 dm_crypt raid10 raid456 > > libcrc32c async_raid6_recov async_memcpy async_pq async_xor xor > > async_tx raid6_pq raid1 raid0 joydev input_leds hid_generic usbhid hid > > nouveau i915 drm_ttm_helper gpu_sched drm_gpuvm drm_exec > i2c_algo_bit > > drm_buddy ttm drm_display_helper drm_kms_helper cec rc_core drm nvme > > nvme_core mxm_wmi xhci_pci xhci_pci_renesas video wmi > > pinctrl_cannonlake mac_hid ---[ end trace 0000000000000000 ]--- > > > > Fix this by avoiding the divide if bpp is 0. > > > > Fixes: c1d6a22b7219 ("drm/dp: Add helpers to calculate the link BW > > overhead") > > Signed-off-by: Chris Bainbridge <chris.bainbridge@xxxxxxxxx> > > --- > > drivers/gpu/drm/display/drm_dp_helper.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/gpu/drm/display/drm_dp_helper.c > > b/drivers/gpu/drm/display/drm_dp_helper.c > > index b1ca3a1100da..bb8794c8f99c 100644 > > --- a/drivers/gpu/drm/display/drm_dp_helper.c > > +++ b/drivers/gpu/drm/display/drm_dp_helper.c > > @@ -4024,6 +4024,9 @@ int drm_dp_bw_overhead(int lane_count, int > hactive, > > bpp_x16, > symbol_size, > > is_mst); > > > > + /* Avoid potential divide by zero in DIV_ROUND_UP_ULL */ > > + if (bpp_x16 == 0) > > + return 0; > > return DIV_ROUND_UP_ULL(mul_u32_u32(symbol_cycles * > symbol_size * lane_count, > > overhead * 16), > > hactive * bpp_x16); > > P. P.S.: > > #regzbot duplicate: > https://lore.kernel.org/all/ZcfpqwnkSoiJxeT9@debian.local/ > #regzbot poke
