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From: KP Singh <kpsingh@kernel.org>
To: bpf@vger.kernel.org
Cc: Andrii Nakryiko <andrii@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Florent Revest <revest@chromium.org>,
	Brendan Jackman <jackmanb@chromium.org>
Subject: [PATCH bpf-next v2 1/2] bpf: Allow usage of BPF ringbuffer in sleepable programs
Date: Thu,  4 Feb 2021 19:36:21 +0000	[thread overview]
Message-ID: <20210204193622.3367275-2-kpsingh@kernel.org> (raw)
In-Reply-To: <20210204193622.3367275-1-kpsingh@kernel.org>

The BPF ringbuffer map is pre-allocated and the implementation logic
does not rely on disabling preemption or per-cpu data structures. Using
the BPF ringbuffer sleepable LSM and tracing programs does not trigger
any warnings with DEBUG_ATOMIC_SLEEP, DEBUG_PREEMPT,
PROVE_RCU and PROVE_LOCKING and LOCKDEP enabled.

This allows helpers like bpf_copy_from_user and bpf_ima_inode_hash to
write to the BPF ring buffer from sleepable BPF programs.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: KP Singh <kpsingh@kernel.org>
---
 kernel/bpf/verifier.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5e09632efddb..4c33b4840438 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -10024,6 +10024,8 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
 				return -EINVAL;
 			}
 			break;
+		case BPF_MAP_TYPE_RINGBUF:
+			break;
 		default:
 			verbose(env,
 				"Sleepable programs can only use array and hash maps\n");
-- 
2.30.0.365.g02bc693789-goog


  reply	other threads:[~2021-02-04 19:37 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-04 19:36 [PATCH bpf-next v2 0/2] BPF Ringbuffer + Sleepable Programs KP Singh
2021-02-04 19:36 ` KP Singh [this message]
2021-02-04 20:57   ` [PATCH bpf-next v2 1/2] bpf: Allow usage of BPF ringbuffer in sleepable programs Song Liu
2021-02-05  1:15     ` Andrii Nakryiko
2021-02-04 19:36 ` [PATCH bpf-next v2 2/2] bpf/selftests: Update the IMA test to use BPF ring buffer KP Singh
2021-02-05  7:06 ` [PATCH bpf-next v2 0/2] BPF Ringbuffer + Sleepable Programs Andrii Nakryiko

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