From: Peter Zijlstra <peterz@infradead.org>
To: mhiramat@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
mingo@kernel.org, rostedt@goodmis.org,
naveen.n.rao@linux.vnet.ibm.com, ananth@linux.ibm.com,
x86@kernel.org
Subject: [PATCH 0/2] kprobes: Remove kprobe::fault_handler
Date: Tue, 25 May 2021 09:25:18 +0200 [thread overview]
Message-ID: <20210525072518.791889911@infradead.org> (raw)
The reason for kprobe::fault_handler(), as given by their comment:
* We come here because instructions in the pre/post
* handler caused the page_fault, this could happen
* if handler tries to access user space by
* copy_from_user(), get_user() etc. Let the
* user-specified handler try to fix it first.
Is just plain bad. Those other handlers are ran from non-preemptible
context and had better use _nofault() functions. Also, there is no
upstream usage of this.
The corollary of this change is that no tracing/probing/whatever can consume
faults.
next reply other threads:[~2021-05-25 7:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-25 7:25 Peter Zijlstra [this message]
2021-05-25 7:25 ` [PATCH 1/2] kprobes: Remove kprobe::fault_handler Peter Zijlstra
2021-05-25 14:06 ` Masami Hiramatsu
2021-05-26 10:50 ` Naveen N. Rao
2021-05-26 13:51 ` Masami Hiramatsu
2021-06-01 12:01 ` [PATCH] kprobes: Do not increment probe miss count in the fault handler Naveen N. Rao
2021-06-01 13:20 ` Peter Zijlstra
2021-06-01 23:48 ` Masami Hiramatsu
2021-06-04 13:38 ` [tip: perf/core] " tip-bot2 for Naveen N. Rao
2021-06-01 14:04 ` [tip: perf/core] kprobes: Remove kprobe::fault_handler tip-bot2 for Peter Zijlstra
2021-05-25 7:25 ` [PATCH 2/2] x86,kprobes: WARN if kprobes tries to handle a fault Peter Zijlstra
2021-05-25 14:21 ` Masami Hiramatsu
2021-06-01 14:04 ` [tip: perf/core] " tip-bot2 for Peter Zijlstra
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=20210525072518.791889911@infradead.org \
--to=peterz@infradead.org \
--cc=ananth@linux.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mhiramat@kernel.org \
--cc=mingo@kernel.org \
--cc=naveen.n.rao@linux.vnet.ibm.com \
--cc=rostedt@goodmis.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).