From: tip-bot for Masami Hiramatsu <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: bp@alien8.de, davem@davemloft.net, ananth@linux.vnet.ibm.com,
dvlasenk@redhat.com, peterz@infradead.org, brgerst@gmail.com,
mhiramat@kernel.org, torvalds@linux-foundation.org,
anil.s.keshavamurthy@intel.com, aryabinin@virtuozzo.com,
tglx@linutronix.de, xiaolong.ye@intel.com,
linux-kernel@vger.kernel.org, jpoimboe@redhat.com, hpa@zytor.com,
mingo@kernel.org
Subject: [tip:perf/core] kprobes/x86: Do not modify singlestep buffer while resuming
Date: Wed, 12 Apr 2017 00:33:33 -0700 [thread overview]
Message-ID: <tip-804dec5bda9b4fcdab5f67fe61db4a0498af5221@git.kernel.org> (raw)
In-Reply-To: <149076361560.22469.1610155860343077495.stgit@devbox>
Commit-ID: 804dec5bda9b4fcdab5f67fe61db4a0498af5221
Gitweb: http://git.kernel.org/tip/804dec5bda9b4fcdab5f67fe61db4a0498af5221
Author: Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 29 Mar 2017 14:00:25 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 12 Apr 2017 09:23:45 +0200
kprobes/x86: Do not modify singlestep buffer while resuming
Do not modify singlestep execution buffer (kprobe.ainsn.insn)
while resuming from single-stepping, instead, modifies
the buffer to add a jump back instruction at preparing
buffer.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ye Xiaolong <xiaolong.ye@intel.com>
Link: http://lkml.kernel.org/r/149076361560.22469.1610155860343077495.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/kprobes/core.c | 42 ++++++++++++++++++++----------------------
1 file changed, 20 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 6327f95..a654054 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -399,23 +399,36 @@ int __copy_instruction(u8 *dest, u8 *src)
return length;
}
+/* Prepare reljump right after instruction to boost */
+static void prepare_boost(struct kprobe *p, int length)
+{
+ if (can_boost(p->ainsn.insn, p->addr) &&
+ MAX_INSN_SIZE - length >= RELATIVEJUMP_SIZE) {
+ /*
+ * These instructions can be executed directly if it
+ * jumps back to correct address.
+ */
+ synthesize_reljump(p->ainsn.insn + length, p->addr + length);
+ p->ainsn.boostable = 1;
+ } else {
+ p->ainsn.boostable = -1;
+ }
+}
+
static int arch_copy_kprobe(struct kprobe *p)
{
- int ret;
+ int len;
/* Copy an instruction with recovering if other optprobe modifies it.*/
- ret = __copy_instruction(p->ainsn.insn, p->addr);
- if (!ret)
+ len = __copy_instruction(p->ainsn.insn, p->addr);
+ if (!len)
return -EINVAL;
/*
* __copy_instruction can modify the displacement of the instruction,
* but it doesn't affect boostable check.
*/
- if (can_boost(p->ainsn.insn, p->addr))
- p->ainsn.boostable = 0;
- else
- p->ainsn.boostable = -1;
+ prepare_boost(p, len);
/* Check whether the instruction modifies Interrupt Flag or not */
p->ainsn.if_modifier = is_IF_modifier(p->ainsn.insn);
@@ -878,21 +891,6 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs,
break;
}
- if (p->ainsn.boostable == 0) {
- if ((regs->ip > copy_ip) &&
- (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) {
- /*
- * These instructions can be executed directly if it
- * jumps back to correct address.
- */
- synthesize_reljump((void *)regs->ip,
- (void *)orig_ip + (regs->ip - copy_ip));
- p->ainsn.boostable = 1;
- } else {
- p->ainsn.boostable = -1;
- }
- }
-
regs->ip += orig_ip - copy_ip;
no_change:
next prev parent reply other threads:[~2017-04-12 7:39 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 4:55 [RFC PATCH tip/master V3 0/8] kprobes/x86: Make kprobes instruction buffers read-only Masami Hiramatsu
2017-03-29 4:56 ` [RFC PATCH tip/master V3 1/8] kprobes/x86: Fix not to boost call far instruction Masami Hiramatsu
2017-04-12 7:32 ` [tip:perf/core] kprobes/x86: Fix kprobe-booster not to boost far call instructions tip-bot for Masami Hiramatsu
2017-03-29 4:58 ` [RFC PATCH tip/master V3 2/8] kprobes/x86: Fix the description of __copy_instruction() Masami Hiramatsu
2017-04-12 7:32 ` [tip:perf/core] " tip-bot for Masami Hiramatsu
2017-03-29 4:59 ` [RFC PATCH tip/master V3 3/8] kprobes/x86: Use instruction decoder for booster Masami Hiramatsu
2017-04-12 7:33 ` [tip:perf/core] " tip-bot for Masami Hiramatsu
2017-03-29 5:00 ` [RFC PATCH tip/master V3 4/8] kprobes/x86: Do not modify singlestep buffer while resuming Masami Hiramatsu
2017-04-12 7:33 ` tip-bot for Masami Hiramatsu [this message]
2017-03-29 5:01 ` [RFC PATCH tip/master V3 5/8] kprobes/x86: Make boostable flag boolean Masami Hiramatsu
2017-04-12 7:34 ` [tip:perf/core] " tip-bot for Masami Hiramatsu
2017-03-29 5:02 ` [RFC PATCH tip/master V3 6/8] kprobes/x86: Set kprobes pages readonly Masami Hiramatsu
2017-04-12 7:34 ` [tip:perf/core] kprobes/x86: Set kprobes pages read-only tip-bot for Masami Hiramatsu
2017-03-29 5:03 ` [RFC PATCH tip/master V3 7/8] kprobes/x86: Use probe_kernel_read instead of memcpy Masami Hiramatsu
2017-04-12 7:35 ` [tip:perf/core] kprobes/x86: Use probe_kernel_read() instead of memcpy() tip-bot for Masami Hiramatsu
2017-03-29 5:05 ` [RFC PATCH tip/master V3 8/8] kprobes/x86: Consolidate insn decoder users for copying code Masami Hiramatsu
2017-04-12 7:35 ` [tip:perf/core] " tip-bot for Masami Hiramatsu
2017-04-11 5:44 ` [RFC PATCH tip/master V3 0/8] kprobes/x86: Make kprobes instruction buffers read-only Masami Hiramatsu
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