From: Miroslav Benes <mbenes@suse.cz>
To: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
Huacai Chen <chenhuacai@kernel.org>,
Xi Zhang <zhangxi@kylinos.cn>,
live-patching@vger.kernel.org, loongarch@lists.linux.dev,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 2/2] LoongArch: Return 0 for user tasks in arch_stack_walk_reliable()
Date: Thu, 11 Sep 2025 15:44:53 +0200 (CEST) [thread overview]
Message-ID: <alpine.LSU.2.21.2509111541590.29971@pobox.suse.cz> (raw)
In-Reply-To: <20250909113106.22992-3-yangtiezhu@loongson.cn>
Hi,
On Tue, 9 Sep 2025, Tiezhu Yang wrote:
> When testing the kernel live patching with "modprobe livepatch-sample",
> there is a timeout over 15 seconds from "starting patching transition"
> to "patching complete", dmesg shows "unreliable stack" for user tasks
> in debug mode. When executing "rmmod livepatch-sample", there exists
> the similar issue.
>
> Like x86, arch_stack_walk_reliable() should return 0 for user tasks.
> It is necessary to set regs->csr_prmd as task->thread.csr_prmd first,
> then use user_mode() to check whether the task is in userspace.
it is a nice optimization for sure, but "unreliable stack" messages point
to a fact that the unwinding of these tasks is probably suboptimal and
could be improved, no?
It would also be nice to include these messages (not for all tasks) to the
commit message.
Regards
Miroslav
next prev parent reply other threads:[~2025-09-11 13:44 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-09 11:31 [PATCH v1 0/2] Debug and fix livepatch issues on LoongArch Tiezhu Yang
2025-09-09 11:31 ` [PATCH v1 1/2] livepatch: Add config LIVEPATCH_DEBUG to get debug information Tiezhu Yang
2025-09-11 13:50 ` Miroslav Benes
2025-09-12 2:26 ` Tiezhu Yang
2025-09-12 7:14 ` Miroslav Benes
2025-09-09 11:31 ` [PATCH v1 2/2] LoongArch: Return 0 for user tasks in arch_stack_walk_reliable() Tiezhu Yang
2025-09-10 1:11 ` Jinyang He
2025-09-11 11:49 ` Tiezhu Yang
2025-09-12 1:55 ` Jinyang He
2025-09-15 8:54 ` Tiezhu Yang
2025-09-11 13:44 ` Miroslav Benes [this message]
2025-09-15 8:48 ` Tiezhu Yang
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