linux-kernel - Re: [PATCH v3,1/2] media: mediatek: vcodec: adding lock to protect decoder context list

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Message-ID: <cf9ec761b77b57995c22dd6a9e67ee0738b3d5e5.camel@collabora.com>
Date: Mon, 26 Feb 2024 16:32:37 -0500
From: Nicolas Dufresne <nicolas.dufresne@...labora.com>
To: Yunfei Dong <yunfei.dong@...iatek.com>, Nícolas "F .
 R . A . Prado" <nfraprado@...labora.com>, Hans Verkuil
 <hverkuil-cisco@...all.nl>, AngeloGioacchino Del Regno
 <angelogioacchino.delregno@...labora.com>, Benjamin Gaignard
 <benjamin.gaignard@...labora.com>, Nathan Hebert <nhebert@...omium.org>, 
 Irui Wang <irui.wang@...iatek.com>
Cc: Hsin-Yi Wang <hsinyi@...omium.org>, Fritz Koenig
 <frkoenig@...omium.org>,  Daniel Vetter <daniel@...ll.ch>, Steve Cho
 <stevecho@...omium.org>, linux-media@...r.kernel.org, 
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org, 
 Project_Global_Chrome_Upstream_Group@...iatek.com, Steve Cho
 <stevecho@...gle.com>
Subject: Re: [PATCH v3,1/2] media: mediatek: vcodec: adding lock to protect
 decoder context list

Hi Yunfei,

Le lundi 26 février 2024 à 14:39 -0500, Nicolas Dufresne a écrit :
> Hi,
> 
> Le jeudi 22 février 2024 à 17:26 +0800, Yunfei Dong a écrit :
> > The ctx_list will be deleted when scp getting unexpected behavior, then the
> > ctx_list->next will be NULL, the kernel driver maybe access NULL pointer in
> > function vpu_dec_ipi_handler when going through each context, then reboot.
> > 
> > Need to add lock to protect the ctx_list to make sure the ctx_list->next isn't
> > NULL pointer.
> 
> The cited crash no longer occurs for me, but it still sometimes crashes while
> the SCP being rebooted. I think this patch can still go in, as it overall
> improves the situation.
> 
> Meanwhile, here's my stress test using GStreamer and stream downloaded by
> fluster. I call this script few times this way as it does not always crash. The
> test just keep starting decode sessions and terminate them after 2 seconds. It
> is highly parallel. Using too low number does not reproduce the crash, using too
> high number leads to alloc failure, which wasn't the goal of this test.

I just sent a fix for that crash, it was limited to HEVC.

https://lore.kernel.org/all/20240226211954.400891-1-nicolas.dufresne@collabora.com/

With this applied, the kernel no longer crash. But the SCP get reset every-time
I run the script below. Will you be able to provide a firmware (or driver if
that turns out to the issue) for this ?

regards,
Nicolas

> 
> ./mtk-vcodec-crash.sh 100

> 
> Script code:
> ***
> #!/bin/bash
> 
> test() {
> 	gst-launch-1.0 --no-fault filesrc location=TILES_B_Cisco_1.bin ! h265parse ! v4l2slh265dec ! fakevideosink &
> 	pid=$!
> 
> 	sleep 2
> 	kill $pid
> }
> 
> for i in $(seq 1 $1)
> do
> 	test &
> done
> 
> wait
> ***
> 
> The kernel Crash:
> [   93.261248] Unable to handle kernel NULL pointer dereference at virtual
> address 0000000000000008
> [   93.270056] Mem abort info:
> [   93.272880]   ESR = 0x0000000096000004
> [   93.276804]   EC = 0x25: DABT (current EL), IL = 32 bits
> [   93.282233]   SET = 0, FnV = 0
> [   93.285372]   EA = 0, S1PTW = 0
> [   93.288561]   FSC = 0x04: level 0 translation fault
> [   93.293493] Data abort info:
> [   93.296424]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
> [   93.301920]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
> [   93.306977]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
> [   93.312321] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000168daf000
> [   93.318790] [0000000000000008] pgd=0000000000000000, p4d=0000000000000000
> [   93.325588] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
> [   93.331842] Modules linked in: mt7921e mt7921_common mt792x_lib
> mt76_connac_lib mt76 mac80211 btusb btintel mtk_vcodec_dec_hw btmtk btrtl
> mtk_vcodec_dec btbcm cfg80211 bluetooth snd_sof_mt8195 mtk_vcodec_enc
> mtk_adsp_common uvcvideo v4l2_vp9 snd_sof_xtensa_dsp v4l2_h264 mtk_vcodec_dbgfs
> snd_sof_of snd_sof ecdh_generic mtk_vcodec_common ecc uvc elan_i2c
> videobuf2_vmalloc crct10dif_ce cros_ec_lid_angle cros_ec_sensors snd_sof_utils
> cros_ec_sensors_core cros_usbpd_logger cros_usbpd_charger fuse ip_tables ipv6
> [   93.376652] CPU: 5 PID: 3210 Comm: h265parse0:sink Tainted: G        W      
> 6.8.0-rc4-next-20240212+ #14
> [   93.386463] Hardware name: Acer Tomato (rev3 - 4) board (DT)
> [   93.392107] pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [   93.399054] pc : vcodec_vpu_send_msg+0x4c/0x190 [mtk_vcodec_dec]
> [   93.405058] lr : vcodec_send_ap_ipi+0x78/0x170 [mtk_vcodec_dec]
> [   93.410968] sp : ffff80008750bc20
> [   93.414269] x29: ffff80008750bc20 x28: ffff1299f6d70000 x27: 0000000000000000
> [   93.421391] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
> [   93.428512] x23: ffff80008750bc98 x22: 000000000000a003 x21: ffffd45c4cfae000
> [   93.435632] x20: 0000000000000010 x19: ffff1299fd668310 x18: 000000000000001a
> [   93.442753] x17: 000000040044ffff x16: ffffd45cb15dc648 x15: 0000000000000000
> [   93.449874] x14: ffff1299c08da1c0 x13: ffffd45cb1f87a10 x12: ffffd45cb2f5fe80
> [   93.456995] x11: 0000000000000001 x10: 0000000000001b30 x9 : ffffd45c4d12b488
> [   93.464116] x8 : 1fffe25339380d81 x7 : 0000000000000001 x6 : ffff1299c9c06c00
> [   93.471236] x5 : 0000000000000132 x4 : 0000000000000000 x3 : 0000000000000000
> [   93.478358] x2 : 0000000000000010 x1 : ffff80008750bc98 x0 : 0000000000000000
> [   93.485479] Call trace:
> [   93.487914]  vcodec_vpu_send_msg+0x4c/0x190 [mtk_vcodec_dec]
> [   93.493563]  vcodec_send_ap_ipi+0x78/0x170 [mtk_vcodec_dec]
> [   93.499125]  vpu_dec_deinit+0x1c/0x30 [mtk_vcodec_dec]
> [   93.504254]  vdec_hevc_slice_deinit+0x30/0x98 [mtk_vcodec_dec]
> [   93.510076]  vdec_if_deinit+0x38/0x68 [mtk_vcodec_dec]
> [   93.515205]  mtk_vcodec_dec_release+0x20/0x40 [mtk_vcodec_dec]
> [   93.521027]  fops_vcodec_release+0x64/0x118 [mtk_vcodec_dec]
> [   93.526677]  v4l2_release+0x7c/0x100
> [   93.530245]  __fput+0x80/0x2d8
> [   93.533292]  __fput_sync+0x58/0x70
> [   93.536681]  __arm64_sys_close+0x40/0x90
> [   93.540590]  invoke_syscall+0x50/0x128
> [   93.544329]  el0_svc_common.constprop.0+0x48/0xf0
> [   93.549020]  do_el0_svc+0x24/0x38
> [   93.552323]  el0_svc+0x38/0xd8
> [   93.555367]  el0t_64_sync_handler+0xc0/0xc8
> [   93.559537]  el0t_64_sync+0x1a8/0x1b0
> [   93.563189] Code: d503201f f9401660 b900127f b900227f (f9400400) 
> [   93.569268] ---[ end trace 0000000000000000 ]---
>