From: Oleg Nesterov <oleg@redhat.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
"David S. Miller" <davem@davemloft.net>, X86 ML <x86@kernel.org>,
Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: Why do kprobes and uprobes singlestep?
Date: Tue, 2 Mar 2021 21:31:34 +0100 [thread overview]
Message-ID: <20210302203134.GC21871@redhat.com> (raw)
In-Reply-To: <20210302112224.6b3568434be490fbfbdec790@kernel.org>
On 03/02, Masami Hiramatsu wrote:
>
> > Not sure I understand you correctly, I know almost nothing about low-level
> > x86 magic.
>
> x86 has normal interrupt and NMI. When an NMI occurs the CPU masks NMI
> (the mask itself is hidden status) and IRET releases the mask. The problem
> is that if an INT3 is hit in the NMI handler and does a single-stepping,
> it has to use IRET for atomically setting TF and return.
Ah, thanks a lot,
Oleg.
prev parent reply other threads:[~2021-03-02 22:37 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 23:24 Why do kprobes and uprobes singlestep? Andy Lutomirski
2021-02-24 1:17 ` Masami Hiramatsu
2021-02-24 19:45 ` Andy Lutomirski
2021-02-25 2:22 ` Masami Hiramatsu
2021-02-25 6:03 ` Andy Lutomirski
2021-02-25 9:11 ` Masami Hiramatsu
2021-03-01 14:08 ` [RFC PATCH 0/1] x86/kprobes: Remoev single-step trap from x86 kprobes Masami Hiramatsu
2021-03-01 14:08 ` [RFC PATCH 1/1] x86/kprobes: Use int3 instead of debug trap for single-step Masami Hiramatsu
2021-03-02 8:06 ` Peter Zijlstra
2021-03-02 8:38 ` Peter Zijlstra
2021-03-02 8:41 ` Peter Zijlstra
2021-03-02 8:54 ` Peter Zijlstra
2021-03-02 12:51 ` Masami Hiramatsu
2021-03-02 13:58 ` Peter Zijlstra
2021-03-02 15:25 ` [PATCH -tip 0/3] x86/kprobes: Remoev single-step trap from x86 kprobes Masami Hiramatsu
2021-03-02 15:25 ` [PATCH -tip 1/3] x86/kprobes: Retrieve correct opcode for group instruction Masami Hiramatsu
2021-03-23 15:15 ` [tip: x86/core] " tip-bot2 for Masami Hiramatsu
2021-03-02 15:25 ` [PATCH -tip 2/3] x86/kprobes: Identify far indirect JMP correctly Masami Hiramatsu
2021-03-23 15:15 ` [tip: x86/core] " tip-bot2 for Masami Hiramatsu
2021-03-02 15:25 ` [PATCH -tip 3/3] x86/kprobes: Use int3 instead of debug trap for single-step Masami Hiramatsu
2021-03-23 15:15 ` [tip: x86/core] " tip-bot2 for Masami Hiramatsu
2021-03-17 14:55 ` [PATCH -tip 0/3] x86/kprobes: Remoev single-step trap from x86 kprobes Masami Hiramatsu
2021-03-17 16:26 ` Peter Zijlstra
2021-03-17 17:45 ` Andy Lutomirski
2021-02-25 9:59 ` Why do kprobes and uprobes singlestep? Peter Zijlstra
2021-03-01 16:51 ` Oleg Nesterov
2021-03-02 1:36 ` Andy Lutomirski
2021-03-02 20:24 ` Alexei Starovoitov
2021-03-02 21:02 ` Andy Lutomirski
2021-03-03 1:22 ` Alexei Starovoitov
2021-03-03 1:46 ` Andy Lutomirski
2021-03-03 2:18 ` Alexei Starovoitov
2021-03-03 13:27 ` Oleg Nesterov
2021-03-03 18:11 ` Daniel Xu
2021-03-03 19:14 ` Andy Lutomirski
2021-03-02 20:25 ` Oleg Nesterov
2021-03-02 20:35 ` Andy Lutomirski
2021-03-02 20:28 ` Oleg Nesterov
2021-03-02 2:22 ` Masami Hiramatsu
2021-03-02 2:48 ` Andy Lutomirski
2021-03-02 20:31 ` Oleg Nesterov [this message]
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