From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Mark Brown <broonie@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
x86@kernel.org, Jinchao Wang <wangjinchao600@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Ian Rogers <irogers@google.com>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, Aishwarya.TCV@arm.com
Subject: Re: [PATCH v5 6/8] selftests: tracing: Add a basic testcase for wprobe
Date: Wed, 29 Oct 2025 17:20:04 +0900 [thread overview]
Message-ID: <20251029172004.a0aca144735f20a6a59d2aa6@kernel.org> (raw)
In-Reply-To: <20251029114317.167b7d908533385c1c9e6782@kernel.org>
On Wed, 29 Oct 2025 11:43:17 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> > Hmm, it seems that jiffies related things are updated frequently
> > and it may cause interrupt storm or infinit recursive call.
>
> I added another trace_printk() in el1_watchpt(). It seems el1_watchpt()
> takes too long and there is no time to do any other things.
> (Note the interval shown below is only within the el1_watchpt function,
> and in reality various processes (save/restore registers etc) for
> exception handling will be inserted before and after.)
Forget about this. I found the root cause. The x86 watchpoint exception
happens after the instruction is executed, the arm64 happens before.
Thus what we need is to emulate or do single step the hooked instruction
and restart from the next instruction from the watchpoint exception on
arm64. I thought hw_breakpoint does that, but doesn't. Should we do this
in do_watchpoint() or in user_handler?
Thank you,
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2025-10-29 8:20 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-23 1:16 [PATCH v5 0/8] tracing: wprobe: Add wprobe for watchpoint Masami Hiramatsu (Google)
2025-09-23 1:16 ` [PATCH v5 1/8] tracing: wprobe: Add watchpoint probe event based on hardware breakpoint Masami Hiramatsu (Google)
2025-10-01 0:30 ` Masami Hiramatsu
2025-09-23 1:17 ` [PATCH v5 2/8] x86/hw_breakpoint: Unify breakpoint install/uninstall Masami Hiramatsu (Google)
2025-09-23 1:17 ` [PATCH v5 3/8] x86/hw_breakpoint: Add arch_reinstall_hw_breakpoint Masami Hiramatsu (Google)
2025-09-23 1:17 ` [PATCH v5 4/8] HWBP: Add modify_wide_hw_breakpoint_local() API Masami Hiramatsu (Google)
2025-09-23 1:17 ` [PATCH v5 5/8] tracing: wprobe: Add wprobe event trigger Masami Hiramatsu (Google)
2025-09-23 1:17 ` [PATCH v5 6/8] selftests: tracing: Add a basic testcase for wprobe Masami Hiramatsu (Google)
2025-10-24 21:31 ` Mark Brown
2025-10-27 2:29 ` Masami Hiramatsu
2025-10-27 13:43 ` Masami Hiramatsu
2025-10-27 23:42 ` Masami Hiramatsu
2025-10-28 1:55 ` Masami Hiramatsu
2025-10-28 15:42 ` Masami Hiramatsu
2025-10-29 2:43 ` Masami Hiramatsu
2025-10-29 8:20 ` Masami Hiramatsu [this message]
2025-10-30 0:09 ` Masami Hiramatsu
2025-11-12 12:15 ` Mark Brown
2025-11-12 13:30 ` Masami Hiramatsu
2025-09-23 1:17 ` [PATCH v5 7/8] selftests: tracing: Add syntax " Masami Hiramatsu (Google)
2025-09-23 1:18 ` [PATCH v5 8/8] selftests: ftrace: Add wprobe trigger testcase Masami Hiramatsu (Google)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20251029172004.a0aca144735f20a6a59d2aa6@kernel.org \
--to=mhiramat@kernel.org \
--cc=Aishwarya.TCV@arm.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=bp@alien8.de \
--cc=broonie@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=irogers@google.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=wangjinchao600@gmail.com \
--cc=will@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).