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Subject: Re: [PATCH v2 0/2] arm: Replace this_cpu_* with raw_cpu_* in
 panic_bad_stack()
To:     "Russell King (Oracle)" <linux@armlinux.org.uk>
CC:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <patches@armlinux.org.uk>
References: <20220826095112.289-1-thunder.leizhen@huawei.com>
 <YxinJcixamAEO2yr@shell.armlinux.org.uk>
From:   "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
Message-ID: <4e153b71-5bb4-d2ee-1feb-0ffd33d48ef5@huawei.com>
Date:   Thu, 8 Sep 2022 09:47:10 +0800
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On 2022/9/7 22:13, Russell King (Oracle) wrote:
> Please distinguish your patches/patch series between arch/arm and
> arch/arm64. The two are maintained separately, and it gets quite
> annoying to read messages nd then realise that they're not for 32-bit
> ARM, but are for arm64/aarch64.

OK, I'm sorry for causing you any trouble.

> 
> Thanks.
> 
> On Fri, Aug 26, 2022 at 05:51:10PM +0800, Zhen Lei wrote:
>> v1 --> v2:
>> Update commit message of two patches.
>>
>> v1:
>> I'm analyzing a strange problem these days, and I find that there are some areas in
>> panic_bad_stack() that can be optimized. That is, replace this_cpu_* with raw_cpu_* .
>>
>> Just optimization, it is unlikely to cause the following exception nesting, because of
>> "lr : __bad_stack+0x88/0x8c".
>>
>> [20220819163739]Unable to handle kernel paging request at virtual address f7ffff94901b8048
>> [20220819163739]Mem abort info:
>> [20220819163739]  ESR = 0x96000004
>> [20220819163739]  EC = 0x25: DABT (current EL), IL = 32 bits
>> [20220819163739]  SET = 0, FnV = 0
>> [20220819163739]  EA = 0, S1PTW = 0
>> [20220819163739]Data abort info:
>> [20220819163739]  ISV = 0, ISS = 0x00000004
>> [20220819163739]  CM = 0, WnR = 0
>> [20220819163739][f7ffff94901b8048] address between user and kernel address ranges
>> [20220819163739]Internal error: Oops: 96000004 [#1] PREEMPT SMP
>> [20220819163739]Modules linked in: ...
>> [20220819163740]CPU: 2 PID: 1272 Comm: 00002SWDLMain Tainted: G        W  O      5.10.0 #1
>> [20220819163740]Hardware name: hisilicon,hi1213-fpga (DT)
>> [20220819163740]pstate: 000003c5 (nzcv DAIF -PAN -UAO -TCO BTYPE=--)
>> [20220819163740]pc : __bad_stack+0x4c/0x8c
>> [20220819163740]lr : __bad_stack+0x88/0x8c
>> [20220819163740]sp : ffffff953ffa8160
>> [20220819163740]x29: f7ffff953ffa8120 x28: f7ffff94901b8040 
>> [20220819163740]x27: ffffffeb72ea6940 x26: ffffffebeee6cf10 
>> [20220819163740]x25: ffffffebef627000 x24: 0000000000000000 
>> [20220819163740]x23: 00000000600003c5 x22: f7ffffebeee11904 
>> [20220819163740]x21: ffffff953ffa82b0 x20: 0000007fffffffff 
>> [20220819163740]x19: f7ffffc0133ab898 x18: 0000000000000000 
>> [20220819163740]x17: 0000000000000000 x16: ffffffebef32f0a0 
>> [20220819163740]x15: 00000000624057a0 x14: 953325a7da350fb3 
>> [20220819163740]x13: 09bbbe32ce2b3c11 x12: c15a0e2d1991997b 
>> [20220819163740]x11: 0bc8be839e7850d0 x10: cafa1cb223203045 
>> [20220819163740]x9 : f36bed299e5840dc x8 : ffffffc0133aba48 
>> [20220819163740]x7 : ffffff953b1b0480 x6 : ffffffebef3e1000 
>> [20220819163740]x5 : 0000000000000000 x4 : 0000000000000001 
>> [20220819163740]x3 : f7ffffc0133ab750 x2 : 0000000000000025 
>> [20220819163740]x1 : 0000000096000004 x0 : ffffff953ffa8160 
>> [20220819163740]Call trace:
>> [20220819163740] __bad_stack+0x4c/0x8c
>> [20220819163740]Code: a90d6ffa a90e77fc 910543f5 d538411c (f9400794) 
>> [20220819163740]---[ end trace 07532bfa2c24851c ]---
>> [20220819163740]Kernel panic - not syncing: Oops: Fatal exception
>>
>> Zhen Lei (2):
>>   arm64/traps: Replace this_cpu_* with raw_cpu_* in panic_bad_stack()
>>   ARM: replace this_cpu_* with raw_cpu_* in panic_bad_stack()
>>
>>  arch/arm/kernel/traps.c   | 4 ++--
>>  arch/arm64/kernel/traps.c | 4 ++--
>>  2 files changed, 4 insertions(+), 4 deletions(-)
>>
>> -- 
>> 2.25.1
>>
>>
> 

-- 
Regards,
  Zhen Lei