On Thu, 7 May 2026 15:44:33 +0200 Martin Kaiser <[email protected]> wrote:
> Running the kprobes sanity tests twice makes all tests fail and > eventually crashes the kernel. > > [root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run > ... > # Totals: pass:5 fail:0 skip:0 total:5 > ok 1 kprobes_test > [root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run > ... > # test_kprobe: EXPECTATION FAILED at lib/tests/test_kprobes.c:64 > Expected 0 == register_kprobe(&kp), but > register_kprobe(&kp) == -22 (0xffffffffffffffea) > ... > Unable to handle kernel paging request ... Oops, good catch! Thanks for fixing! > > The testsuite defines several kprobes and kretprobes as static variables > that are preserved across test runs. > > After register_kprobe and unregister_kprobe, a kprobe contains some > leftover data that must be cleared before the kprobe can be registered > again. The tests are setting symbol_name to define the probe location. > Address and flags must be cleared. > > The existing code clears some of the probes between subsequent tests, but > not between two test runs. The leftover data from a previous test run > makes the registrations fail in the next run. > > Move the cleanups for all kprobes into kprobes_test_init, this function > is called before each single test (including the first test of a test > run). Yeah, this looks good to me. Let me pick it. > > Signed-off-by: Martin Kaiser <[email protected]> > --- > lib/tests/test_kprobes.c | 29 ++++++++++++++++++----------- > 1 file changed, 18 insertions(+), 11 deletions(-) > > diff --git a/lib/tests/test_kprobes.c b/lib/tests/test_kprobes.c > index b7582010125c..06e729e4de05 100644 > --- a/lib/tests/test_kprobes.c > +++ b/lib/tests/test_kprobes.c > @@ -12,6 +12,12 @@ > > #define div_factor 3 > > +#define KP_CLEAR(_kp) \ > +do { \ > + (_kp).addr = NULL; \ > + (_kp).flags = 0; \ > +} while (0) > + > static u32 rand1, preh_val, posth_val; > static u32 (*target)(u32 value); > static u32 (*recursed_target)(u32 value); > @@ -125,10 +131,6 @@ static void test_kprobes(struct kunit *test) > > current_test = test; > > - /* addr and flags should be cleard for reusing kprobe. */ > - kp.addr = NULL; > - kp.flags = 0; > - > KUNIT_EXPECT_EQ(test, 0, register_kprobes(kps, 2)); > preh_val = 0; > posth_val = 0; > @@ -226,9 +228,6 @@ static void test_kretprobes(struct kunit *test) > struct kretprobe *rps[2] = {&rp, &rp2}; > > current_test = test; > - /* addr and flags should be cleard for reusing kprobe. */ > - rp.kp.addr = NULL; > - rp.kp.flags = 0; > KUNIT_EXPECT_EQ(test, 0, register_kretprobes(rps, 2)); > > krph_val = 0; > @@ -290,8 +289,6 @@ static void test_stacktrace_on_kretprobe(struct kunit > *test) > unsigned long myretaddr = (unsigned long)__builtin_return_address(0); > > current_test = test; > - rp3.kp.addr = NULL; > - rp3.kp.flags = 0; > > /* > * Run the stacktrace_driver() to record correct return address in > @@ -352,8 +349,6 @@ static void test_stacktrace_on_nested_kretprobe(struct > kunit *test) > struct kretprobe *rps[2] = {&rp3, &rp4}; > > current_test = test; > - rp3.kp.addr = NULL; > - rp3.kp.flags = 0; > > //KUNIT_ASSERT_NE(test, myretaddr, stacktrace_driver()); > > @@ -367,6 +362,18 @@ static void test_stacktrace_on_nested_kretprobe(struct > kunit *test) > > static int kprobes_test_init(struct kunit *test) > { > + KP_CLEAR(kp); > + KP_CLEAR(kp2); > + KP_CLEAR(kp_missed); > +#ifdef CONFIG_KRETPROBES > + KP_CLEAR(rp.kp); > + KP_CLEAR(rp2.kp); > +#ifdef CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE > + KP_CLEAR(rp3.kp); > + KP_CLEAR(rp4.kp); > +#endif > +#endif > + > target = kprobe_target; > target2 = kprobe_target2; > recursed_target = kprobe_recursed_target; > -- > 2.43.7 > -- Masami Hiramatsu (Google) <[email protected]>
