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| author | Eduard Zingerman <eddyz87@gmail.com> | 2026-09-04 17:05:56 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-09-04 18:17:30 -0700 |
| commit | 506ada89629ec7059b96ecfb0dc7d33ece0103ca (patch) | |
| tree | 0b07297409b68d2333fb4f0eae7f3b072eb68d4c /Documentation/networking/skbuff.rst | |
| download | linux-stable-506ada89629ec7059b96ecfb0dc7d33ece0103ca.tar.gz linux-stable-506ada89629ec7059b96ecfb0dc7d33ece0103ca.zip | |
bpf: mark a NULL kfunc argument precisegrafted
check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.
Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'Documentation/networking/skbuff.rst')
| -rw-r--r-- | Documentation/networking/skbuff.rst | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/networking/skbuff.rst b/Documentation/networking/skbuff.rst new file mode 100644 index 000000000..94681523e --- /dev/null +++ b/Documentation/networking/skbuff.rst @@ -0,0 +1,31 @@ +.. SPDX-License-Identifier: GPL-2.0 + +struct sk_buff +============== + +:c:type:`sk_buff` is the main networking structure representing +a packet. + +Basic sk_buff geometry +---------------------- + +.. kernel-doc:: include/linux/skbuff.h + :doc: Basic sk_buff geometry + +Shared skbs and skb clones +-------------------------- + +:c:member:`sk_buff.users` is a simple refcount allowing multiple entities +to keep a struct sk_buff alive. skbs with a ``sk_buff.users != 1`` are referred +to as shared skbs (see skb_shared()). + +skb_clone() allows for fast duplication of skbs. None of the data buffers +get copied, but caller gets a new metadata struct (struct sk_buff). +&skb_shared_info.refcount indicates the number of skbs pointing at the same +packet data (i.e. clones). + +dataref and headerless skbs +--------------------------- + +.. kernel-doc:: include/linux/skbuff.h + :doc: dataref and headerless skbs |