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[bpf-next] bpf: Fix the irq and nmi check in bpf_sk_storage for tracing usage

Message ID 20201116200113.2868539-1-kafai@fb.com
State New
Headers show
Series [bpf-next] bpf: Fix the irq and nmi check in bpf_sk_storage for tracing usage | expand

Commit Message

Martin KaFai Lau Nov. 16, 2020, 8:01 p.m. UTC
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: 8e4597c627fb ("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>
---
 net/core/bpf_sk_storage.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Nov. 17, 2020, 1 a.m. UTC | #1
Hello:

This patch was applied to bpf/bpf-next.git (refs/heads/master):

On Mon, 16 Nov 2020 12:01:13 -0800 you wrote:
> 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: 8e4597c627fb ("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>
> 
> [...]

Here is the summary with links:
  - [bpf-next] bpf: Fix the irq and nmi check in bpf_sk_storage for tracing usage
    https://git.kernel.org/bpf/bpf-next/c/b93ef089d35c

You are awesome, thank you!
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diff mbox series

Patch

diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index 359908a7d3c1..a32037daa933 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -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);