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Message-ID: <9f0b3333-bb28-c739-9bff-6fc50343b4f9@gmx.de>
Date:   Mon, 10 Oct 2022 08:16:22 +0200
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Subject: Re: [PATCH v3 4/4] arc: Use generic dump_stack_print_cmdline()
 implementation
Content-Language: en-US
To:     Vineet Gupta <vineet.gupta@linux.dev>, linux-s390@vger.kernel.org,
        Josh Triplett <josh@joshtriplett.org>, x86@kernel.org,
        linux-snps-arc@lists.infradead.org, linux-fsdevel@vger.kernel.org,
        linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org
Cc:     Alexey Brodkin <abrodkin@synopsys.com>,
        Shahab Vahedi <Shahab.Vahedi@synopsys.com>
References: <20220808130917.30760-1-deller@gmx.de>
 <20220808130917.30760-5-deller@gmx.de>
 <8da9812d-eb84-2a84-321e-ea2826ef8981@linux.dev>
From:   Helge Deller <deller@gmx.de>
In-Reply-To: <8da9812d-eb84-2a84-321e-ea2826ef8981@linux.dev>
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On 10/10/22 07:18, Vineet Gupta wrote:
> On 8/8/22 06:09, Helge Deller wrote:
>> The process program name and command line is now shown in generic code
>> in dump_stack_print_info(), so drop the arc-specific implementation.
>>
>> Signed-off-by: Helge Deller <deller@gmx.de>
>
> But that info printing was added back in 2018 by e36df28f532f882.
> I don't think arc is using show_regs_print_info -> dump_stack_print_info=
 yet.
> Or is there a different code path now which calls here ?

Right.
See patches #1 and #2 of this series which added this
info to dump_stack_print_info().


>> ---
>> =C2=A0 arch/arc/kernel/troubleshoot.c | 24 ------------------------
>> =C2=A0 1 file changed, 24 deletions(-)
>>
>> diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troublesh=
oot.c
>> index 7654c2e42dc0..9807e590ee55 100644
>> --- a/arch/arc/kernel/troubleshoot.c
>> +++ b/arch/arc/kernel/troubleshoot.c
>> @@ -51,29 +51,6 @@ static void print_regs_callee(struct callee_regs *re=
gs)
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 regs->r24, regs-=
>r25);
>> =C2=A0 }
>>
>> -static void print_task_path_n_nm(struct task_struct *tsk)
>> -{
>> -=C2=A0=C2=A0=C2=A0 char *path_nm =3D NULL;
>> -=C2=A0=C2=A0=C2=A0 struct mm_struct *mm;
>> -=C2=A0=C2=A0=C2=A0 struct file *exe_file;
>> -=C2=A0=C2=A0=C2=A0 char buf[ARC_PATH_MAX];
>> -
>> -=C2=A0=C2=A0=C2=A0 mm =3D get_task_mm(tsk);
>> -=C2=A0=C2=A0=C2=A0 if (!mm)
>> -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 goto done;
>> -
>> -=C2=A0=C2=A0=C2=A0 exe_file =3D get_mm_exe_file(mm);
>> -=C2=A0=C2=A0=C2=A0 mmput(mm);
>> -
>> -=C2=A0=C2=A0=C2=A0 if (exe_file) {
>> -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 path_nm =3D file_path(exe_f=
ile, buf, ARC_PATH_MAX-1);
>> -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 fput(exe_file);
>> -=C2=A0=C2=A0=C2=A0 }
>> -
>> -done:
>> -=C2=A0=C2=A0=C2=A0 pr_info("Path: %s\n", !IS_ERR(path_nm) ? path_nm : =
"?");
>> -}
>> -
>> =C2=A0 static void show_faulting_vma(unsigned long address)
>> =C2=A0 {
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 struct vm_area_struct *vma;
>> @@ -176,7 +153,6 @@ void show_regs(struct pt_regs *regs)
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 */
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 preempt_enable();
>
> Maybe we remove preempt* as well now (perhaps as a follow up patch)
> since that was added by f731a8e89f8c78 "ARC: show_regs: lockdep:
> re-enable preemption" where show_regs -> print_task_path_n_nm ->
> mmput was triggering lockdep splat which is supposedly removed.

The patch series was dropped from Andrew's queue, because the kernel
test robot showed some issues:
https://lore.kernel.org/lkml/Yu59QdVpPgnXUnQC@xsang-OptiPlex-9020/
Maybe adding preempt_enable() in my patches would fix that -
sadly I haven't had time to follow up on this yet ...

Helge

>
>>
>> -=C2=A0=C2=A0=C2=A0 print_task_path_n_nm(tsk);
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 show_regs_print_info(KERN_INFO);
>>
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 show_ecr_verbose(regs);