> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 1f74fce27677..8d90575aa77d 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
[ ... ]
> @@ -2530,10 +2537,14 @@ static int try_charge_memcg(struct mem_cgroup *memcg,
> gfp_t gfp_mask,
> * kernel. If this is successful, the return path will see it
> * when it rechecks the overage and simply bail out.
> */
> - if (current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH &&
> - !(current->flags & PF_MEMALLOC) &&
> - gfpflags_allow_blocking(gfp_mask))
> - __mem_cgroup_handle_over_high(gfp_mask);
> + if (gfpflags_allow_blocking(gfp_mask)) {
> + unsigned long bpf_high_delay;
> +
> + bpf_high_delay = bpf_memcg_get_high_delay(orig_memcg);
> + if (bpf_high_delay ||
> + current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH)
> + __mem_cgroup_handle_over_high(gfp_mask, bpf_high_delay);
> + }
The old code checked !(current->flags & PF_MEMALLOC) before calling
__mem_cgroup_handle_over_high(). This check appears to be missing in the
new code.
When PF_MEMALLOC is set, the task is already in the memory reclaim context.
Calling __mem_cgroup_handle_over_high() from such a context would invoke
reclaim_high() -> try_to_free_mem_cgroup_pages(), potentially causing
reclaim recursion.
Was the removal of the PF_MEMALLOC check intentional? If a BPF program
returns a non-zero delay from get_high_delay_ms while the task is in a
reclaim context, could this lead to recursive reclaim or deadlock?
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/21392729810
AI-authorship-score: low
AI-authorship-explanation: The code shows typical human characteristics
including a refactoring oversight that AI would likely not make; the commit
follows standard kernel conventions and has multiple human authors.
issues-found: 1
issue-severity-score: medium
issue-severity-explanation: Missing PF_MEMALLOC check could cause memory
reclaim recursion when BPF programs are attached, potentially leading to system
instability.
