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bpf: Fix the irq and nmi check in bpf_sk_storage for tracing usage

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The intention of the current check is to avoid using bpf_sk_storage
in irq and nmi.  Jakub pointed out that the current check cannot
do that.  For example, in_serving_softirq() returns true
if the softirq handling is interrupted by hard irq.

Fixes: 8e4597c627 ("bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201116200113.2868539-1-kafai@fb.com
This commit is contained in:
Martin KaFai Lau
2020-11-16 12:01:13 -08:00
committed by Alexei Starovoitov
parent 024cd2cbd1
commit b93ef089d3
1 changed files with 2 additions and 2 deletions
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4
net/core/bpf_sk_storage.c
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@@ -415,7 +415,7 @@ static bool bpf_sk_storage_tracing_allowed(const struct bpf_prog *prog)
BPF_CALL_4(bpf_sk_storage_get_tracing, struct bpf_map *, map, struct sock *, sk,
void *, value, u64, flags)
{
if (!in_serving_softirq() && !in_task())
if (in_irq() || in_nmi())
return (unsigned long)NULL;
return (unsigned long)____bpf_sk_storage_get(map, sk, value, flags);
@@ -424,7 +424,7 @@ BPF_CALL_4(bpf_sk_storage_get_tracing, struct bpf_map *, map, struct sock *, sk,
BPF_CALL_2(bpf_sk_storage_delete_tracing, struct bpf_map *, map,
struct sock *, sk)
{
if (!in_serving_softirq() && !in_task())
if (in_irq() || in_nmi())
return -EPERM;
return ____bpf_sk_storage_delete(map, sk);