From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Joe Lawrence <joe.lawrence@redhat.com>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: [for-next][PATCH 01/25] kprobes: Allow kprobes coexist with livepatch
Date: Thu, 05 Sep 2019 11:42:59 -0400 [thread overview]
Message-ID: <20190905154339.451160440@goodmis.org> (raw)
In-Reply-To: 20190905154258.573706229@goodmis.org
From: Masami Hiramatsu <mhiramat@kernel.org>
Allow kprobes which do not modify regs->ip, coexist with livepatch
by dropping FTRACE_OPS_FL_IPMODIFY from ftrace_ops.
User who wants to modify regs->ip (e.g. function fault injection)
must set a dummy post_handler to its kprobes when registering.
However, if such regs->ip modifying kprobes is set on a function,
that function can not be livepatched.
Link: http://lkml.kernel.org/r/156403587671.30117.5233558741694155985.stgit@devnote2
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/kprobes.c | 56 ++++++++++++++++++++++++++++++++++--------------
1 file changed, 40 insertions(+), 16 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index d9770a5393c8..f57deec96ba1 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -961,9 +961,16 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
#ifdef CONFIG_KPROBES_ON_FTRACE
static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
+ .func = kprobe_ftrace_handler,
+ .flags = FTRACE_OPS_FL_SAVE_REGS,
+};
+
+static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
.func = kprobe_ftrace_handler,
.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
};
+
+static int kprobe_ipmodify_enabled;
static int kprobe_ftrace_enabled;
/* Must ensure p->addr is really on ftrace */
@@ -976,58 +983,75 @@ static int prepare_kprobe(struct kprobe *p)
}
/* Caller must lock kprobe_mutex */
-static int arm_kprobe_ftrace(struct kprobe *p)
+static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+ int *cnt)
{
int ret = 0;
- ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
- (unsigned long)p->addr, 0, 0);
+ ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
if (ret) {
pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n",
p->addr, ret);
return ret;
}
- if (kprobe_ftrace_enabled == 0) {
- ret = register_ftrace_function(&kprobe_ftrace_ops);
+ if (*cnt == 0) {
+ ret = register_ftrace_function(ops);
if (ret) {
pr_debug("Failed to init kprobe-ftrace (%d)\n", ret);
goto err_ftrace;
}
}
- kprobe_ftrace_enabled++;
+ (*cnt)++;
return ret;
err_ftrace:
/*
- * Note: Since kprobe_ftrace_ops has IPMODIFY set, and ftrace requires a
- * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental
- * empty filter_hash which would undesirably trace all functions.
+ * At this point, sinec ops is not registered, we should be sefe from
+ * registering empty filter.
*/
- ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0);
+ ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
return ret;
}
+static int arm_kprobe_ftrace(struct kprobe *p)
+{
+ bool ipmodify = (p->post_handler != NULL);
+
+ return __arm_kprobe_ftrace(p,
+ ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+ ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
+
/* Caller must lock kprobe_mutex */
-static int disarm_kprobe_ftrace(struct kprobe *p)
+static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+ int *cnt)
{
int ret = 0;
- if (kprobe_ftrace_enabled == 1) {
- ret = unregister_ftrace_function(&kprobe_ftrace_ops);
+ if (*cnt == 1) {
+ ret = unregister_ftrace_function(ops);
if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret))
return ret;
}
- kprobe_ftrace_enabled--;
+ (*cnt)--;
- ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
- (unsigned long)p->addr, 1, 0);
+ ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n",
p->addr, ret);
return ret;
}
+
+static int disarm_kprobe_ftrace(struct kprobe *p)
+{
+ bool ipmodify = (p->post_handler != NULL);
+
+ return __disarm_kprobe_ftrace(p,
+ ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+ ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
#else /* !CONFIG_KPROBES_ON_FTRACE */
#define prepare_kprobe(p) arch_prepare_kprobe(p)
#define arm_kprobe_ftrace(p) (-ENODEV)
--
2.20.1
next prev parent reply other threads:[~2019-09-05 15:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 15:42 [for-next][PATCH 00/25] tracing: Updates for 5.4 Steven Rostedt
2019-09-05 15:42 ` Steven Rostedt [this message]
2019-09-05 15:43 ` [for-next][PATCH 02/25] recordmcount: Remove redundant strcmp Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 03/25] recordmcount: Remove uread() Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 04/25] recordmcount: Remove unused fd from uwrite() and ulseek() Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 05/25] tracing/probe: Split trace_event related data from trace_probe Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 06/25] tracing/dynevent: Delete all matched events Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 07/25] tracing/dynevent: Pass extra arguments to match operation Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 08/25] tracing/kprobe: Add multi-probe per event support Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 09/25] tracing/uprobe: Add multi-probe per uprobe " Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 10/25] tracing/kprobe: Add per-probe delete from event Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 11/25] tracing/uprobe: " Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 12/25] tracing/probe: Add immediate parameter support Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 13/25] tracing/probe: Add immediate string " Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 14/25] selftests/ftrace: Add a testcase for kprobe multiprobe event Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 15/25] selftests/ftrace: Add syntax error test for immediates Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 16/25] selftests/ftrace: Add syntax error test for multiprobe Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 17/25] recordmcount: Rewrite error/success handling Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 18/25] recordmcount: Kernel style function signature formatting Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 19/25] recordmcount: Kernel style formatting Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 20/25] recordmcount: Remove redundant cleanup() calls Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 21/25] recordmcount: Clarify what cleanup() does Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 22/25] tracing/arm64: Have max stack tracer handle the case of return address after data Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 23/25] tracing: Document the stack trace algorithm in the comments Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 24/25] tracing: Rename tracing_reset() to tracing_reset_cpu() Steven Rostedt
2019-09-05 15:43 ` [for-next][PATCH 25/25] tracing: Add "gfp_t" support in synthetic_events Steven Rostedt
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