From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Florent Revest <revest@chromium.org>,
Will Deacon <will@kernel.org>
Subject: [for-next][PATCH 05/25] fprobe: Skip exit_handler if entry_handler returns !0
Date: Wed, 29 Mar 2023 15:45:21 -0400 [thread overview]
Message-ID: <20230329194550.004033858@goodmis.org> (raw)
In-Reply-To: <20230329194516.146147554@goodmis.org>
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Skip hooking function return and calling exit_handler if the
entry_handler() returns !0.
Link: https://lkml.kernel.org/r/167526699798.433354.10998365726830117303.stgit@mhiramat.roam.corp.google.com
Cc: Florent Revest <revest@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
include/linux/fprobe.h | 4 ++--
kernel/trace/bpf_trace.c | 15 +++++++++++++--
kernel/trace/fprobe.c | 14 +++++++++-----
lib/test_fprobe.c | 7 +++++--
samples/fprobe/fprobe_example.c | 5 +++--
5 files changed, 32 insertions(+), 13 deletions(-)
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index 678f741a7b33..47fefc7f363b 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -34,8 +34,8 @@ struct fprobe {
size_t entry_data_size;
int nr_maxactive;
- void (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
- struct pt_regs *regs, void *entry_data);
+ int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
+ struct pt_regs *regs, void *entry_data);
void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
struct pt_regs *regs, void *entry_data);
};
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index fa403c323501..d804172b709c 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2644,12 +2644,23 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
return err;
}
-static void
+static int
kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
struct pt_regs *regs, void *data)
{
struct bpf_kprobe_multi_link *link;
+ link = container_of(fp, struct bpf_kprobe_multi_link, fp);
+ kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
+ return 0;
+}
+
+static void
+kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
+ struct pt_regs *regs, void *data)
+{
+ struct bpf_kprobe_multi_link *link;
+
link = container_of(fp, struct bpf_kprobe_multi_link, fp);
kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
}
@@ -2848,7 +2859,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
goto error;
if (flags & BPF_F_KPROBE_MULTI_RETURN)
- link->fp.exit_handler = kprobe_multi_link_handler;
+ link->fp.exit_handler = kprobe_multi_link_exit_handler;
else
link->fp.entry_handler = kprobe_multi_link_handler;
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index f222848571f2..9abb3905bc8e 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -27,7 +27,7 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
struct rethook_node *rh = NULL;
struct fprobe *fp;
void *entry_data = NULL;
- int bit;
+ int bit, ret;
fp = container_of(ops, struct fprobe, ops);
if (fprobe_disabled(fp))
@@ -52,11 +52,15 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
}
if (fp->entry_handler)
- fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
-
- if (rh)
- rethook_hook(rh, ftrace_get_regs(fregs), true);
+ ret = fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
+ /* If entry_handler returns !0, nmissed is not counted. */
+ if (rh) {
+ if (ret)
+ rethook_recycle(rh);
+ else
+ rethook_hook(rh, ftrace_get_regs(fregs), true);
+ }
out:
ftrace_test_recursion_unlock(bit);
}
diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c
index 4b37d7022f35..9fa2ac9eda83 100644
--- a/lib/test_fprobe.c
+++ b/lib/test_fprobe.c
@@ -37,7 +37,7 @@ static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32))
return nest(value + 2);
}
-static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip,
+static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
struct pt_regs *regs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
@@ -51,6 +51,8 @@ static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip,
*(u32 *)data = entry_val;
} else
KUNIT_EXPECT_NULL(current_test, data);
+
+ return 0;
}
static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
@@ -74,10 +76,11 @@ static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
KUNIT_EXPECT_NULL(current_test, data);
}
-static notrace void nest_entry_handler(struct fprobe *fp, unsigned long ip,
+static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip,
struct pt_regs *regs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
+ return 0;
}
static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c
index dd794990ad7e..4efc8feb6277 100644
--- a/samples/fprobe/fprobe_example.c
+++ b/samples/fprobe/fprobe_example.c
@@ -48,8 +48,8 @@ static void show_backtrace(void)
stack_trace_print(stacks, len, 24);
}
-static void sample_entry_handler(struct fprobe *fp, unsigned long ip,
- struct pt_regs *regs, void *data)
+static int sample_entry_handler(struct fprobe *fp, unsigned long ip,
+ struct pt_regs *regs, void *data)
{
if (use_trace)
/*
@@ -62,6 +62,7 @@ static void sample_entry_handler(struct fprobe *fp, unsigned long ip,
nhit++;
if (stackdump)
show_backtrace();
+ return 0;
}
static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs,
--
2.39.1
next prev parent reply other threads:[~2023-03-29 19:46 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-29 19:45 [for-next][PATCH 00/25] tracing: Updates for 6.4 Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 01/25] fprobe: Pass entry_data to handlers Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 02/25] lib/test_fprobe: Add private entry_data testcases Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 03/25] fprobe: Add nr_maxactive to specify rethook_node pool size Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 04/25] lib/test_fprobe: Add a test case for nr_maxactive Steven Rostedt
2023-03-29 19:45 ` Steven Rostedt [this message]
2023-03-29 19:45 ` [for-next][PATCH 06/25] lib/test_fprobe: Add a testcase for skipping exit_handler Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 07/25] docs: tracing: Update fprobe documentation Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 08/25] selftests: use canonical ftrace path Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 09/25] leaking_addresses: also skip " Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 10/25] tools/kvm_stat: use " Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 11/25] tracing: Add "fields" option to show raw trace event fields Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 12/25] tracing/user_events: Split header into uapi and kernel Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 13/25] tracing/user_events: Track fork/exec/exit for mm lifetime Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 14/25] tracing/user_events: Use remote writes for event enablement Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 15/25] tracing/user_events: Fixup enable faults asyncly Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 16/25] tracing/user_events: Add ioctl for disabling addresses Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 17/25] tracing/user_events: Update self-tests to write ABI Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 18/25] tracing/user_events: Add ABI self-test Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 19/25] tracing/user_events: Use write ABI in example Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 20/25] tracing/user_events: Update documentation for ABI Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 21/25] tracing/user_events: Charge event allocs to cgroups Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 22/25] tracing/user_events: Limit global user_event count Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 23/25] tracing/user_events: Align structs with tabs for readability Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 24/25] tracing/user_events: Use print_format_fields() for trace output Steven Rostedt
2023-03-29 19:45 ` [for-next][PATCH 25/25] tracing: Unbreak user events Steven Rostedt
2023-03-29 20:29 ` Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230329194550.004033858@goodmis.org \
--to=rostedt@goodmis.org \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mhiramat@kernel.org \
--cc=revest@chromium.org \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®