From: Masami Hiramatsu <mhiramat@kernel.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: peterz@infradead.org, Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org, Eddy_Wu@trendmicro.com,
x86@kernel.org, davem@davemloft.net, rostedt@goodmis.org,
naveen.n.rao@linux.ibm.com, anil.s.keshavamurthy@intel.com,
linux-arch@vger.kernel.org, cameron@moodycamel.com,
oleg@redhat.com, will@kernel.org, paulmck@kernel.org,
systemtap@sourceware.org
Subject: Re: [PATCH v5 00/21] kprobes: Unify kretprobe trampoline handlers and make kretprobe lockless
Date: Thu, 3 Sep 2020 11:02:26 +0900 [thread overview]
Message-ID: <20200903110226.8963179e6a7c978e2d56c595@kernel.org> (raw)
In-Reply-To: <20200903103954.68f0c97da57b3679169ce3a7@kernel.org>
On Thu, 3 Sep 2020 10:39:54 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> OK, I've confirmed that the lockdep warns on kretprobe from INT3
> with your fix. Of course make it lockless then warning is gone.
> But even without the lockless patch, this warning can be false-positive
> because we prohibit nested kprobe call, right?
>
> If the kprobe user handler uses a spinlock, the spinlock is used
> only in that handler (and in the context between kprobe_busy_begin/end),
> it will be safe since the spinlock is not nested.
> But if the spinlock is shared with other context, it will be dangerous
> because it can be interrupted by NMI (including INT3). This also applied
> to the function which is called from kprobe user handlers, thus user
> has to take care of it.
Sorry, for noticing this point, I Cc'd to systemtap. Is systemtap taking
care of spinlock too?
Thank you,
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2020-09-03 2:02 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-29 12:59 [PATCH v5 00/21] kprobes: Unify kretprobe trampoline handlers and make kretprobe lockless Masami Hiramatsu
2020-08-29 13:00 ` [PATCH v5 01/21] kprobes: Add generic kretprobe trampoline handler Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:00 ` [PATCH v5 02/21] x86/kprobes: Use " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:00 ` [PATCH v5 03/21] arm: kprobes: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:00 ` [PATCH v5 04/21] arm64: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:00 ` [PATCH v5 05/21] arc: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:00 ` [PATCH v5 06/21] csky: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:01 ` [PATCH v5 07/21] ia64: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:01 ` [PATCH v5 08/21] mips: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:01 ` [PATCH v5 09/21] parisc: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:01 ` [PATCH v5 10/21] powerpc: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:02 ` [PATCH v5 11/21] s390: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:02 ` [PATCH v5 12/21] sh: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:02 ` [PATCH v5 13/21] sparc: " Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-08-29 13:02 ` [PATCH v5 14/21] kprobes: Remove NMI context check Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
2020-10-31 1:38 ` [PATCH v5 14/21] " Steven Rostedt
2020-11-02 5:11 ` Masami Hiramatsu
2020-11-02 5:53 ` Masami Hiramatsu
2020-11-02 7:02 ` Masami Hiramatsu
2020-11-02 14:27 ` Steven Rostedt
2020-11-03 5:39 ` Masami Hiramatsu
2020-11-03 16:09 ` Steven Rostedt
2020-11-04 2:08 ` Masami Hiramatsu
2020-11-04 14:47 ` Steven Rostedt
2020-11-05 5:15 ` Masami Hiramatsu
2020-08-29 13:02 ` [PATCH v5 15/21] kprobes: Free kretprobe_instance with rcu callback Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] kprobes: Free kretprobe_instance with RCU callback tip-bot2 for Masami Hiramatsu
2020-08-29 13:03 ` [PATCH v5 16/21] kprobes: Make local used functions static Masami Hiramatsu
2020-09-14 17:16 ` [tip: perf/kprobes] kprobes: Make local " tip-bot2 for Masami Hiramatsu
2020-08-29 13:03 ` [PATCH v5 17/21] llist: Add nonatomic __llist_add() and __llist_dell_all() Masami Hiramatsu
2020-10-12 16:24 ` Ingo Molnar
2020-10-14 0:24 ` Masami Hiramatsu
2020-10-12 17:08 ` [tip: perf/kprobes] " tip-bot2 for Peter Zijlstra
2020-08-29 13:03 ` [PATCH v5 18/21] kprobes: Remove kretprobe hash Masami Hiramatsu
2020-10-12 17:08 ` [tip: perf/kprobes] " tip-bot2 for Peter Zijlstra
2020-08-29 13:03 ` [PATCH v5 19/21] asm-generic/atomic: Add try_cmpxchg() fallbacks Masami Hiramatsu
2020-10-12 16:25 ` Ingo Molnar
2020-10-12 17:08 ` [tip: perf/kprobes] " tip-bot2 for Peter Zijlstra
2020-08-29 13:03 ` [PATCH v5 20/21] freelist: Lock less freelist Masami Hiramatsu
2020-10-12 17:08 ` [tip: perf/kprobes] freelist: Implement lockless freelist tip-bot2 for Peter Zijlstra
2020-08-29 13:03 ` [PATCH v5 21/21] kprobes: Replace rp->free_instance with freelist Masami Hiramatsu
2020-10-12 17:08 ` [tip: perf/kprobes] " tip-bot2 for Peter Zijlstra
2020-09-01 19:08 ` [PATCH v5 00/21] kprobes: Unify kretprobe trampoline handlers and make kretprobe lockless Peter Zijlstra
2020-09-02 0:37 ` Masami Hiramatsu
2020-09-02 7:02 ` peterz
2020-09-02 8:17 ` Masami Hiramatsu
2020-09-02 9:36 ` peterz
2020-09-02 13:19 ` Masami Hiramatsu
2020-09-02 13:42 ` peterz
2020-09-03 1:39 ` Masami Hiramatsu
2020-09-03 2:02 ` Masami Hiramatsu [this message]
2020-09-07 17:44 ` Frank Ch. Eigler
2020-09-08 2:55 ` Masami Hiramatsu
2020-09-08 10:37 ` peterz
2020-09-08 11:15 ` Eddy_Wu
2020-09-08 11:33 ` peterz
2020-09-08 15:09 ` Masami Hiramatsu
2020-09-09 5:28 ` Masami Hiramatsu
2020-09-11 2:32 ` Masami Hiramatsu
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