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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 5.10 10/25] tracing/probes: Reject events which have the same name of existing one
Date: Sat, 11 Sep 2021 09:12:57 -0400	[thread overview]
Message-ID: <20210911131312.285225-10-sashal@kernel.org> (raw)
In-Reply-To: <20210911131312.285225-1-sashal@kernel.org>

From: Masami Hiramatsu <mhiramat@kernel.org>

[ Upstream commit 8e242060c6a4947e8ae7d29794af6a581db08841 ]

Since kprobe_events and uprobe_events only check whether the
other same-type probe event has the same name or not, if the
user gives the same name of the existing tracepoint event (or
the other type of probe events), it silently fails to create
the tracefs entry (but registered.) as below.

/sys/kernel/tracing # ls events/task/task_rename
enable   filter   format   hist     id       trigger
/sys/kernel/tracing # echo p:task/task_rename vfs_read >> kprobe_events
[  113.048508] Could not create tracefs 'task_rename' directory
/sys/kernel/tracing # cat kprobe_events
p:task/task_rename vfs_read

To fix this issue, check whether the existing events have the
same name or not in trace_probe_register_event_call(). If exists,
it rejects to register the new event.

Link: https://lkml.kernel.org/r/162936876189.187130.17558311387542061930.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/trace_kprobe.c |  6 +++++-
 kernel/trace/trace_probe.c  | 25 +++++++++++++++++++++++++
 kernel/trace/trace_probe.h  |  1 +
 kernel/trace/trace_uprobe.c |  6 +++++-
 4 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 68150b9cbde9..552dbc9d5226 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -647,7 +647,11 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
 	/* Register new event */
 	ret = register_kprobe_event(tk);
 	if (ret) {
-		pr_warn("Failed to register probe event(%d)\n", ret);
+		if (ret == -EEXIST) {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(0, EVENT_EXIST);
+		} else
+			pr_warn("Failed to register probe event(%d)\n", ret);
 		goto end;
 	}
 
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index d2867ccc6aca..1d31bc4acf7a 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1029,11 +1029,36 @@ int trace_probe_init(struct trace_probe *tp, const char *event,
 	return ret;
 }
 
+static struct trace_event_call *
+find_trace_event_call(const char *system, const char *event_name)
+{
+	struct trace_event_call *tp_event;
+	const char *name;
+
+	list_for_each_entry(tp_event, &ftrace_events, list) {
+		if (!tp_event->class->system ||
+		    strcmp(system, tp_event->class->system))
+			continue;
+		name = trace_event_name(tp_event);
+		if (!name || strcmp(event_name, name))
+			continue;
+		return tp_event;
+	}
+
+	return NULL;
+}
+
 int trace_probe_register_event_call(struct trace_probe *tp)
 {
 	struct trace_event_call *call = trace_probe_event_call(tp);
 	int ret;
 
+	lockdep_assert_held(&event_mutex);
+
+	if (find_trace_event_call(trace_probe_group_name(tp),
+				  trace_probe_name(tp)))
+		return -EEXIST;
+
 	ret = register_trace_event(&call->event);
 	if (!ret)
 		return -ENODEV;
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 2f703a20c724..6d41e20c47ce 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -398,6 +398,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(NO_EVENT_NAME,	"Event name is not specified"),		\
 	C(EVENT_TOO_LONG,	"Event name is too long"),		\
 	C(BAD_EVENT_NAME,	"Event name must follow the same rules as C identifiers"), \
+	C(EVENT_EXIST,		"Given group/event name is already used by another event"), \
 	C(RETVAL_ON_PROBE,	"$retval is not available on probe"),	\
 	C(BAD_STACK_NUM,	"Invalid stack number"),		\
 	C(BAD_ARG_NUM,		"Invalid argument number"),		\
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 3cf7128e1ad3..0dd6e286e519 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -514,7 +514,11 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 
 	ret = register_uprobe_event(tu);
 	if (ret) {
-		pr_warn("Failed to register probe event(%d)\n", ret);
+		if (ret == -EEXIST) {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(0, EVENT_EXIST);
+		} else
+			pr_warn("Failed to register probe event(%d)\n", ret);
 		goto end;
 	}
 
-- 
2.30.2


  parent reply	other threads:[~2021-09-11 13:17 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-11 13:12 [PATCH AUTOSEL 5.10 01/25] dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 02/25] mfd: db8500-prcmu: Adjust map to reality Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 03/25] PCI: Add ACS quirks for NXP LX2xx0 and LX2xx2 platforms Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 04/25] fuse: fix use after free in fuse_read_interrupt() Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 05/25] PCI: tegra194: Fix handling BME_CHGED event Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 06/25] PCI: tegra194: Fix MSI-X programming Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 07/25] PCI: tegra: Fix OF node reference leak Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 08/25] mfd: Don't use irq_create_mapping() to resolve a mapping Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 09/25] PCI: rcar: Fix runtime PM imbalance in rcar_pcie_ep_probe() Sasha Levin
2021-09-11 13:12 ` Sasha Levin [this message]
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 11/25] PCI: cadence: Use bitfield for *quirk_retrain_flag* instead of bool Sasha Levin
2021-09-11 13:12 ` [PATCH AUTOSEL 5.10 12/25] PCI: cadence: Add quirk flag to set minimum delay in LTSSM Detect.Quiet state Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 13/25] PCI: j721e: Add PCIe support for J7200 Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 14/25] PCI: j721e: Add PCIe support for AM64 Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 15/25] PCI: Add ACS quirks for Cavium multi-function devices Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 16/25] watchdog: Start watchdog in watchdog_set_last_hw_keepalive only if appropriate Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 17/25] octeontx2-af: Add additional register check to rvu_poll_reg() Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 18/25] Set fc_nlinfo in nh_create_ipv4, nh_create_ipv6 Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 19/25] net: usb: cdc_mbim: avoid altsetting toggling for Telit LN920 Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 20/25] block, bfq: honor already-setup queue merges Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 21/25] PCI: ibmphp: Fix double unmap of io_mem Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 22/25] ethtool: Fix an error code in cxgb2.c Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 23/25] NTB: Fix an error code in ntb_msit_probe() Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 24/25] NTB: perf: Fix an error code in perf_setup_inbuf() Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.10 25/25] net: phylink: add suspend/resume support Sasha Levin

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