Date:   Wed, 8 Mar 2023 13:28:01 +0100
From:   Tommaso Merciai <tomm.merciai@gmail.com>
To:     Hal Feng <hal.feng@starfivetech.com>
Cc:     Conor Dooley <conor.dooley@microchip.com>,
        Conor Dooley <conor@kernel.org>,
        linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
        linux-clk@vger.kernel.org, Stephen Boyd <sboyd@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Ben Dooks <ben.dooks@sifive.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Emil Renner Berthing <emil.renner.berthing@canonical.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 00/19] Basic clock, reset & device tree support for
 StarFive JH7110 RISC-V SoC
Message-ID: <ZAh/UeSlUeGoKxki@tom-HP-ZBook-Fury-15-G7-Mobile-Workstation>
References: <20230221024645.127922-1-hal.feng@starfivetech.com>
 <3a605bc8-104e-0935-4fd8-2da16ab9053b@starfivetech.com>
 <ZAb7JVghuiwZF1Q5@wendy>
 <2f03dfb2-5cf8-e954-913c-f0c27db6bcf5@starfivetech.com>
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In-Reply-To: <2f03dfb2-5cf8-e954-913c-f0c27db6bcf5@starfivetech.com>
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Hello Hal/Conor,

On Tue, Mar 07, 2023 at 06:08:53PM +0800, Hal Feng wrote:
> On Tue, 7 Mar 2023 08:51:49 +0000, Conor Dooley wrote:
> > On Tue, Mar 07, 2023 at 04:36:41PM +0800, Hal Feng wrote:
> >> On Tue, 21 Feb 2023 10:46:26 +0800, Hal Feng wrote:
> >> > This patch series adds basic clock, reset & DT support for StarFive
> >> > JH7110 SoC. Patch 17 depends on series [1] which provides pinctrl
> >> > dt-bindings. Patch 19 depends on series [2] which provides dt-bindings
> >> > of VisionFive 2 board and JH7110 SoC.
> >> > 
> >> > You can simply review or test the patches at the link [3].
> >> > 
> >> > [1]: https://lore.kernel.org/all/20230209143702.44408-1-hal.feng@starfivetech.com/
> >> > [2]: https://lore.kernel.org/all/20230216131511.3327943-1-conor.dooley@microchip.com/
> >> > [3]: https://github.com/hal-feng/linux/commits/visionfive2-minimal
> >> 
> >> Hi Conor,
> >> 
> >> When I tried to rebase these patches on v6.3-rc1, I found the kernel
> >> would crash on the VisionFive 2 board during startup. The logs are as
> >> below. I checkout the branch to the mainline and found that the kernel
> >> would also crash on the VisionFive board which is equipped with JH7100
> >> SoC.
> >> 
> >> --------------------------------
> >> Unable to handle kernel paging request at virtual address 0000004cccccccd4
> >> Oops [#1]
> >> Modules linked in:
> >> CPU: 3 PID: 87 Comm: udevd Not tainted 6.3.0-rc1-00019-g239e7809f291 #305
> >> Hardware name: StarFive VisionFive 2 v1.3B (DT)
> >> epc : enqueue_timer+0x18/0x90
> >>  ra : internal_add_timer+0x2c/0x38
> >> epc : ffffffff8006a714 ra : ffffffff8006a7b8 sp : ffffffc80443bc80
> >>  gp : ffffffff80eb5100 tp : ffffffd8c01db200 t0 : 0000000000000000
> >>  t1 : 000000000000000f t2 : 0000000038b3ea28 s0 : ffffffc80443bcb0
> >>  s1 : ffffffff80813940 a0 : ffffffff80813940 a1 : ffffffc80443bd48
> >>  a2 : 000000000000020b a3 : cccccccd0b000000 a4 : cccccccccccccccc
> >>  a5 : 000000000000020b a6 : ffffffff80814a08 a7 : 0000000000000001
> >>  s2 : ffffffc80443bd48 s3 : 0000000008400040 s4 : ffffffff80813940
> >>  s5 : ffffffff80eea0b8 s6 : ffffffff80eb7220 s7 : 0000000000000040
> >>  s8 : ffffffff80eb61e0 s9 : 0000002ac84a2548 s10: 0000002ad53e92c0
> >>  s11: 0000000000000001 t3 : 000000000000003f t4 : 0000000000000000
> >>  t5 : 0000000000000004 t6 : 0000000000000003
> >> status: 0000000200000100 badaddr: 0000004cccccccd4 cause: 000000000000000f
> >> [<ffffffff8006a714>] enqueue_timer+0x18/0x90
> >> [<ffffffff8006aa64>] add_timer_on+0xf0/0x134
> >> [<ffffffff80500f18>] try_to_generate_entropy+0x1ec/0x232
> >> [<ffffffff8035a636>] urandom_read_iter+0x42/0xc2
> >> [<ffffffff800fff16>] vfs_read+0x17c/0x1e4
> >> [<ffffffff801005b6>] ksys_read+0x78/0x98
> >> [<ffffffff801005e4>] sys_read+0xe/0x16
> >> [<ffffffff800035dc>] ret_from_syscall+0x0/0x2
> >> Code: 9381 9713 0037 0813 0705 983a 3703 0008 e198 c311 (e70c) d713 
> >> ---[ end trace 0000000000000000 ]---
> >> note: udevd[87] exited with irqs disabled
> >> Segmentation fault
> >> FAIL
> >> Saving random seed: 
> >> rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
> >> rcu: 	1-...0: (0 ticks this GP) idle=19c4/1/0x4000000000000000 softirq=42/42 fqs=7474
> >> rcu: 	(detected by 2, t=15005 jiffies, g=-195, q=35 ncpus=4)
> >> Task dump for CPU 1:
> >> task:dd              state:R  running task     stack:0     pid:92    ppid:88     flags:0x00000008
> >> Call Trace:
> >> [<ffffffff80003764>] ret_from_fork+0x0/0xc
> >> rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
> >> rcu: 	1-...0: (0 ticks this GP) idle=19c4/1/0x4000000000000000 softirq=42/42 fqs=29814
> >> rcu: 	(detected by 2, t=60018 jiffies, g=-195, q=35 ncpus=4)
> >> Task dump for CPU 1:
> >> task:dd              state:R  running task     stack:0     pid:92    ppid:88     flags:0x00000008
> >> Call Trace:
> >> [<ffffffff80003764>] ret_from_fork+0x0/0xc
> >> ...
> >> --------------------------------
> >> 
> >> I used 'git bisect' and found out the commit 9493e6f3ce02 is the
> >> cause. I tried to revert this commit on the tag v6.3-rc1, but it
> >> seems there is no improvement.
> > 
> > Hmm, I'm not entirely sure that that is a good bisect.
> > This is a fix for my stupidity in the commit you mention:
> > https://lore.kernel.org/linux-riscv/20230302174154.970746-1-conor@kernel.org/
> > 
> > But the main backtrace there is not from that patch at all, I think it
> > is Linus' fault.
> > The HEAD of Linus' tree is currently 8ca09d5fa3549 ("cpumask: fix
> > incorrect cpumask scanning result checks") should be a fix for the
> > backtrace that you are seeing above.
> > 
> >> Any options I am missing? Could you please give me some suggestions
> >> to adapt to the new changes between 6.2 and 6.3? Thank you in
> >> advance.
> > 
> > LMK if the above two things don't fix it for you & I'll go digging
> > tonight.
> 
> The above two methods can fix the problem. Here are my test results.
> The VisionFive board can boot up successfully if and only if all above
> two applied.
> The VisionFive 2 board can boot up successfully if I merge Linus's new
> changes.

Tested also on my side. Hope this can be helpfull.

> 
> Hope your fix will be merged in rc2. Thank you for your reply.

Fully agree.

Regards,
Tommaso

> 
> Best regards,
> Hal