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Subject[PATCH] bpf: verifier: allow arrays of progs to be used in sleepable context
Arrays of progs are underlying using regular arrays, but they can only
be updated from a syscall.
Therefore, they should be safe to use while in a sleepable context.

This is required to be able to call bpf_tail_call() from a sleepable
tracing bpf program.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
---
Hi,

a small patch to allow to have:

```
SEC("fmod_ret.s/__hid_bpf_tail_call_sleepable")
int BPF_PROG(hid_tail_call_sleepable, struct hid_bpf_ctx *hctx)
{
bpf_tail_call(ctx, &hid_jmp_table, hctx->index);

return 0;
}
```

This should allow me to add bpf hooks to functions that communicate with
the hardware.

Cheers,
Benjamin
---
kernel/bpf/verifier.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 68cfd6fc6ad4..880b32795136 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -18171,6 +18171,7 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
case BPF_MAP_TYPE_QUEUE:
case BPF_MAP_TYPE_STACK:
case BPF_MAP_TYPE_ARENA:
+ case BPF_MAP_TYPE_PROG_ARRAY:
break;
default:
verbose(env,
---
base-commit: 735f5b8a7ccf383e50d76f7d1c25769eee474812
change-id: 20240422-sleepable_array_progs-e0c07b17cabb
Best regards,
--
Benjamin Tissoires <bentiss@kernel.org>


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