Subject: Re: [PATCH 1/8] mm: Add ptep_try_set() for lockless empty-slot installs

From: [email-masked]
Date: Mon, 25 May 2026 15:50:13 +0000

Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <[email-masked]>:

On Fri, 22 May 2026 07:22:12 -1000 you wrote:
> Add ptep_try_set(ptep, new_pte): atomically set *ptep to new_pte iff it is
> currently pte_none(). Returns true on success, false if the slot was already
> populated or the arch has no implementation.
> 
> The intended caller is the upcoming bpf_arena kernel-side fault recovery
> path. The install runs from a page fault that can be nested under locks
> held by the faulting kernel caller (e.g. a BPF program holding
> raw_res_spin_lock_irqsave on its arena's spinlock), so trylock-and-retry
> would A-A deadlock. Lock-free cmpxchg is the only viable option, which
> constrains this helper to special kernel page tables where concurrent
> writers cooperate via atomic accessors.
> 
> [...]

Here is the summary with links:
  - [1/8] mm: Add ptep_try_set() for lockless empty-slot installs
    https://git.kernel.org/bpf/bpf-next/c/258df8fce42f
  - [2/8] bpf: Recover arena kernel faults with scratch page
    (no matching commit)
  - [3/8] bpf: Add sleepable variant of bpf_arena_alloc_pages for kernel callers
    https://git.kernel.org/bpf/bpf-next/c/f211c81ddc36
  - [4/8] bpf: Add bpf_struct_ops_for_each_prog()
    https://git.kernel.org/bpf/bpf-next/c/7c48a28c1bbe
  - [5/8] bpf/arena: Add bpf_arena_map_kern_vm_start() and bpf_prog_arena()
    https://git.kernel.org/bpf/bpf-next/c/53cc12a2dc88
  - [6/8] sched_ext: Require an arena for cid-form schedulers
    (no matching commit)
  - [7/8] sched_ext: Sub-allocator over kernel-claimed BPF arena pages
    (no matching commit)
  - [8/8] sched_ext: Convert ops.set_cmask() to arena-resident cmask
    (no matching commit)

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html