Re: [PATCH net v4] netpoll: Fix deadlock in memory allocation under spinlock

From: patchwork-bot+netdevbpf

Date: Tue Nov 04 2025 - 22:40:33 EST


Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@xxxxxxxxxx>:

On Mon, 03 Nov 2025 08:38:17 -0800 you wrote:
> Fix a AA deadlock in refill_skbs() where memory allocation while holding
> skb_pool->lock can trigger a recursive lock acquisition attempt.
>
> The deadlock scenario occurs when the system is under severe memory
> pressure:
>
> 1. refill_skbs() acquires skb_pool->lock (spinlock)
> 2. alloc_skb() is called while holding the lock
> 3. Memory allocator fails and calls slab_out_of_memory()
> 4. This triggers printk() for the OOM warning
> 5. The console output path calls netpoll_send_udp()
> 6. netpoll_send_udp() attempts to acquire the same skb_pool->lock
> 7. Deadlock: the lock is already held by the same CPU
>
> [...]

Here is the summary with links:
- [net,v4] netpoll: Fix deadlock in memory allocation under spinlock
https://git.kernel.org/netdev/net/c/327c20c21d80

You are awesome, thank you!
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