@@ -1658,9 +1658,12 @@ struct bpf_scratchpad {
__be32 diff[MAX_BPF_STACK / sizeof(__be32)];
u8 buff[MAX_BPF_STACK];
};
+ local_lock_t bh_lock;
};
-static DEFINE_PER_CPU(struct bpf_scratchpad, bpf_sp);
+static DEFINE_PER_CPU(struct bpf_scratchpad, bpf_sp) = {
+ .bh_lock = INIT_LOCAL_LOCK(bh_lock),
+};
static inline int __bpf_try_make_writable(struct sk_buff *skb,
unsigned int write_len)
@@ -2029,6 +2032,7 @@ BPF_CALL_5(bpf_csum_diff, __be32 *, from, u32, from_size,
diff_size > sizeof(sp->diff)))
return -EINVAL;
+ guard(local_lock_nested_bh)(&bpf_sp.bh_lock);
for (i = 0; i < from_size / sizeof(__be32); i++, j++)
sp->diff[j] = ~from[i];
for (i = 0; i < to_size / sizeof(__be32); i++, j++)
bpf_scratchpad is a per-CPU variable and relies on disabled BH for its locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT this data structure requires explicit locking. Add a local_lock_t to the data structure and use local_lock_nested_bh() for locking. This change adds only lockdep coverage and does not alter the functional behaviour for !PREEMPT_RT. Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Hao Luo <haoluo@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Fastabend <john.fastabend@gmail.com> Cc: KP Singh <kpsingh@kernel.org> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Song Liu <song@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Yonghong Song <yonghong.song@linux.dev> Cc: bpf@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- net/core/filter.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)