Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
fprobe: Skip exit_handler if entry_handler returns !0
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>
authored by
Masami Hiramatsu (Google)
and committed by
Steven Rostedt (Google)
39d95420
7e7ef1bf
+32
-13
+2
-2
include/linux/fprobe.h
+2
-2
include/linux/fprobe.h
···
34
34
size_t entry_data_size;
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int nr_maxactive;
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37
-
void (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
38
-
struct pt_regs *regs, void *entry_data);
37
+
int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
38
+
struct pt_regs *regs, void *entry_data);
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void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
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struct pt_regs *regs, void *entry_data);
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};
+13
-2
kernel/trace/bpf_trace.c
+13
-2
kernel/trace/bpf_trace.c
···
2644
2644
return err;
2645
2645
}
2646
2646
2647
-
static void
2647
+
static int
2648
2648
kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
2649
2649
struct pt_regs *regs, void *data)
2650
+
{
2651
+
struct bpf_kprobe_multi_link *link;
2652
+
2653
+
link = container_of(fp, struct bpf_kprobe_multi_link, fp);
2654
+
kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
2655
+
return 0;
2656
+
}
2657
+
2658
+
static void
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+
kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
2660
+
struct pt_regs *regs, void *data)
2650
2661
{
2651
2662
struct bpf_kprobe_multi_link *link;
2652
2663
···
2859
2848
goto error;
2860
2849
2861
2850
if (flags & BPF_F_KPROBE_MULTI_RETURN)
2862
-
link->fp.exit_handler = kprobe_multi_link_handler;
2851
+
link->fp.exit_handler = kprobe_multi_link_exit_handler;
2863
2852
else
2864
2853
link->fp.entry_handler = kprobe_multi_link_handler;
2865
2854
+9
-5
kernel/trace/fprobe.c
+9
-5
kernel/trace/fprobe.c
···
27
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struct rethook_node *rh = NULL;
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struct fprobe *fp;
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void *entry_data = NULL;
30
-
int bit;
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+
int bit, ret;
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fp = container_of(ops, struct fprobe, ops);
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if (fprobe_disabled(fp))
···
52
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}
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if (fp->entry_handler)
55
-
fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
55
+
ret = fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
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57
-
if (rh)
58
-
rethook_hook(rh, ftrace_get_regs(fregs), true);
59
-
57
+
/* If entry_handler returns !0, nmissed is not counted. */
58
+
if (rh) {
59
+
if (ret)
60
+
rethook_recycle(rh);
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+
else
62
+
rethook_hook(rh, ftrace_get_regs(fregs), true);
63
+
}
60
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out:
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ftrace_test_recursion_unlock(bit);
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}
+5
-2
lib/test_fprobe.c
+5
-2
lib/test_fprobe.c
···
37
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return nest(value + 2);
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}
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40
-
static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip,
40
+
static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
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struct pt_regs *regs, void *data)
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{
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KUNIT_EXPECT_FALSE(current_test, preemptible());
···
51
51
*(u32 *)data = entry_val;
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} else
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KUNIT_EXPECT_NULL(current_test, data);
54
+
55
+
return 0;
54
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}
55
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static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
···
76
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KUNIT_EXPECT_NULL(current_test, data);
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}
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79
-
static notrace void nest_entry_handler(struct fprobe *fp, unsigned long ip,
77
+
static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip,
80
78
struct pt_regs *regs, void *data)
81
79
{
82
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KUNIT_EXPECT_FALSE(current_test, preemptible());
81
+
return 0;
83
82
}
84
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85
84
static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
+3
-2
samples/fprobe/fprobe_example.c
+3
-2
samples/fprobe/fprobe_example.c
···
48
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stack_trace_print(stacks, len, 24);
49
49
}
50
50
51
-
static void sample_entry_handler(struct fprobe *fp, unsigned long ip,
52
-
struct pt_regs *regs, void *data)
51
+
static int sample_entry_handler(struct fprobe *fp, unsigned long ip,
52
+
struct pt_regs *regs, void *data)
53
53
{
54
54
if (use_trace)
55
55
/*
···
62
62
nhit++;
63
63
if (stackdump)
64
64
show_backtrace();
65
+
return 0;
65
66
}
66
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static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs,