From: Masami Hiramatsu <mhiramat@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
Borislav Petkov <bp@alien8.de>, Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
xen-devel@lists.xenproject.org
Subject: [PATCH -tip 2/2] x86: kprobes: Prohibit probing on instruction which has Xen prefix
Date: Wed, 4 Sep 2019 20:46:09 +0900 [thread overview]
Message-ID: <156759756944.24473.4664241966878257420.stgit@devnote2> (raw)
In-Reply-To: <156759754770.24473.11832897710080799131.stgit@devnote2>
Prohibit probing on instruction which has XEN_EMULATE_PREFIX
(it must be cpuid.) Since that prefix is a marker for Xen,
if we modify the marker by kprobe's int3, that doesn't work
as expected.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/x86/kernel/kprobes/core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 43fc13c831af..b1e86af4a985 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -351,6 +351,10 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn)
kernel_insn_init(insn, dest, MAX_INSN_SIZE);
insn_get_length(insn);
+ /* We can not probe XEN_EMULATE_PREFIX instruction */
+ if (insn_has_xen_prefix(insn))
+ return 0;
+
/* Another subsystem puts a breakpoint, failed to recover */
if (insn->opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
return 0;
next prev parent reply other threads:[~2019-09-04 11:46 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-04 11:45 [PATCH -tip 0/2] x86: Prohibit kprobes on XEN_EMULATE_PREFIX Masami Hiramatsu
2019-09-04 11:45 ` [PATCH -tip 1/2] x86: xen: insn: Decode XEN_EMULATE_PREFIX correctly Masami Hiramatsu
2019-09-04 11:46 ` Masami Hiramatsu [this message]
2019-09-04 11:54 ` [Xen-devel] [PATCH -tip 0/2] x86: Prohibit kprobes on XEN_EMULATE_PREFIX Andrew Cooper
2019-09-05 1:49 ` Masami Hiramatsu
2019-09-05 7:54 ` Andrew Cooper
2019-09-05 8:26 ` Peter Zijlstra
2019-09-05 8:53 ` Andrew Cooper
2019-09-05 9:26 ` Peter Zijlstra
2019-09-05 9:38 ` Andrew Cooper
2019-09-05 12:49 ` [OT] " Masami Hiramatsu
2019-09-05 11:32 ` Masami Hiramatsu
2019-09-05 13:09 ` Masami Hiramatsu
2019-09-05 13:31 ` Andrew Cooper
2019-09-05 16:12 ` Masami Hiramatsu
2019-09-04 12:02 ` Peter Zijlstra
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