Hello:
This patch was applied to bpf/bpf.git (master)
by Martin KaFai Lau <martin.lau@xxxxxxxxxx>:
On Thu, 26 Jan 2023 16:17:32 -0800 you wrote:
> The kernel crash was caused by a BPF program attached to the
> "lsm_cgroup/socket_sock_rcv_skb" hook, which performed a call to
> `bpf_setsockopt()` in order to set the TCP_NODELAY flag as an
> example. Flags like TCP_NODELAY can prompt the kernel to flush a
> socket's outgoing queue, and this hook
> "lsm_cgroup/socket_sock_rcv_skb" is frequently triggered by
> softirqs. The issue was that in certain circumstances, when
> `tcp_write_xmit()` was called to flush the queue, it would also allow
> BH (bottom-half) to run. This could lead to our program attempting to
> flush the same socket recursively, which caused a `skbuf` to be
> unlinked twice.
>
> [...]
Here is the summary with links:
- [bpf,v2] bpf: Fix the kernel crash caused by bpf_setsockopt().
https://git.kernel.org/bpf/bpf/c/5416c9aea832
You are awesome, thank you!
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