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authorDavid Miller <davem@davemloft.net>2020-02-24 15:01:43 +0100
committerAlexei Starovoitov <ast@kernel.org>2020-02-24 16:20:09 -0800
commit3d9f773cf2876c01a505b9fe27270901d464e90a (patch)
treed5ed0350db81b38cf8c0234d7c066f65595addff
parent37e1d9202225635772b32e340294208367279c2b (diff)
bpf: Use bpf_prog_run_pin_on_cpu() at simple call sites.
All of these cases are strictly of the form: preempt_disable(); BPF_PROG_RUN(...); preempt_enable(); Replace this with bpf_prog_run_pin_on_cpu() which wraps BPF_PROG_RUN() with: migrate_disable(); BPF_PROG_RUN(...); migrate_enable(); On non RT enabled kernels this maps to preempt_disable/enable() and on RT enabled kernels this solely prevents migration, which is sufficient as there is no requirement to prevent reentrancy to any BPF program from a preempting task. The only requirement is that the program stays on the same CPU. Therefore, this is a trivially correct transformation. The seccomp loop does not need protection over the loop. It only needs protection per BPF filter program [ tglx: Converted to bpf_prog_run_pin_on_cpu() ] Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200224145643.691493094@linutronix.de
-rw-r--r--include/linux/filter.h4
-rw-r--r--kernel/seccomp.c4
-rw-r--r--net/core/flow_dissector.c4
-rw-r--r--net/core/skmsg.c8
-rw-r--r--net/kcm/kcmsock.c4
5 files changed, 6 insertions, 18 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 1982a52eb4c9..9270de2a0df8 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -717,9 +717,7 @@ static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
if (unlikely(prog->cb_access))
memset(cb_data, 0, BPF_SKB_CB_LEN);
- preempt_disable();
- res = BPF_PROG_RUN(prog, skb);
- preempt_enable();
+ res = bpf_prog_run_pin_on_cpu(prog, skb);
return res;
}
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index b6ea3dcb57bf..787041eb011b 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -268,16 +268,14 @@ static u32 seccomp_run_filters(const struct seccomp_data *sd,
* All filters in the list are evaluated and the lowest BPF return
* value always takes priority (ignoring the DATA).
*/
- preempt_disable();
for (; f; f = f->prev) {
- u32 cur_ret = BPF_PROG_RUN(f->prog, sd);
+ u32 cur_ret = bpf_prog_run_pin_on_cpu(f->prog, sd);
if (ACTION_ONLY(cur_ret) < ACTION_ONLY(ret)) {
ret = cur_ret;
*match = f;
}
}
- preempt_enable();
return ret;
}
#endif /* CONFIG_SECCOMP_FILTER */
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index a1670dff0629..3eff84824c8b 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -920,9 +920,7 @@ bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx,
(int)FLOW_DISSECTOR_F_STOP_AT_ENCAP);
flow_keys->flags = flags;
- preempt_disable();
- result = BPF_PROG_RUN(prog, ctx);
- preempt_enable();
+ result = bpf_prog_run_pin_on_cpu(prog, ctx);
flow_keys->nhoff = clamp_t(u16, flow_keys->nhoff, nhoff, hlen);
flow_keys->thoff = clamp_t(u16, flow_keys->thoff,
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index eeb28cb85664..c479372f2cd2 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -628,7 +628,6 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
struct bpf_prog *prog;
int ret;
- preempt_disable();
rcu_read_lock();
prog = READ_ONCE(psock->progs.msg_parser);
if (unlikely(!prog)) {
@@ -638,7 +637,7 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
sk_msg_compute_data_pointers(msg);
msg->sk = sk;
- ret = BPF_PROG_RUN(prog, msg);
+ ret = bpf_prog_run_pin_on_cpu(prog, msg);
ret = sk_psock_map_verd(ret, msg->sk_redir);
psock->apply_bytes = msg->apply_bytes;
if (ret == __SK_REDIRECT) {
@@ -653,7 +652,6 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
}
out:
rcu_read_unlock();
- preempt_enable();
return ret;
}
EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
@@ -665,9 +663,7 @@ static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog,
skb->sk = psock->sk;
bpf_compute_data_end_sk_skb(skb);
- preempt_disable();
- ret = BPF_PROG_RUN(prog, skb);
- preempt_enable();
+ ret = bpf_prog_run_pin_on_cpu(prog, skb);
/* strparser clones the skb before handing it to a upper layer,
* meaning skb_orphan has been called. We NULL sk on the way out
* to ensure we don't trigger a BUG_ON() in skb/sk operations
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index ea9e73428ed9..56fac24a627a 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -380,9 +380,7 @@ static int kcm_parse_func_strparser(struct strparser *strp, struct sk_buff *skb)
struct bpf_prog *prog = psock->bpf_prog;
int res;
- preempt_disable();
- res = BPF_PROG_RUN(prog, skb);
- preempt_enable();
+ res = bpf_prog_run_pin_on_cpu(prog, skb);
return res;
}