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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-12-08 10:48:41 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-02-20 16:21:56 -0800 |
| commit | eb0339934f1d468ff09d9be1c608c89cb1da850b (patch) | |
| tree | 1ee5394b2d8046eccd2165a853ee1ff5a5338965 /kernel/rcu | |
| parent | e0d31a34c6db6381bfc630a9ee93f05b9447dcc3 (diff) | |
| download | linux-eb0339934f1d468ff09d9be1c608c89cb1da850b.tar.gz | |
rcutorture: Avoid fake-writer use of undefined primitives
Currently the rcu_torture_fakewriter() function invokes cur_ops->sync() and cur_ops->exp_sync() without first checking to see if they are in fact non-NULL. This results in kernel NULL pointer dereferences when testing RCU implementations that choose not to provide the full set of primitives. Given that it is perfectly reasonable to have specialized RCU implementations that provide only a subset of the RCU API, this is a bug in rcutorture. This commit therefore makes rcu_torture_fakewriter() check function pointers before invoking them, thus allowing it to test subsetted RCU implementations. Reported-by: Lihao Liang <lianglihao@huawei.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/rcutorture.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 0f94025c672a..6c46cd1d8fd7 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1045,13 +1045,13 @@ rcu_torture_fakewriter(void *arg) torture_random(&rand) % (nfakewriters * 8) == 0) { cur_ops->cb_barrier(); } else if (gp_normal == gp_exp) { - if (torture_random(&rand) & 0x80) + if (cur_ops->sync && torture_random(&rand) & 0x80) cur_ops->sync(); - else + else if (cur_ops->exp_sync) cur_ops->exp_sync(); - } else if (gp_normal) { + } else if (gp_normal && cur_ops->sync) { cur_ops->sync(); - } else { + } else if (cur_ops->exp_sync) { cur_ops->exp_sync(); } stutter_wait("rcu_torture_fakewriter"); |