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From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Li Jinyue" <jinyue.li@linux.alibaba.com>, <bpf@vger.kernel.org>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>
Cc: "Andrii Nakryiko" <andrii@kernel.org>,
	"Eduard Zingerman" <eddyz87@gmail.com>,
	"Kumar Kartikeya Dwivedi" <memxor@gmail.com>,
	"Martin KaFai Lau" <martin.lau@linux.dev>,
	"Song Liu" <song@kernel.org>,
	"Yonghong Song" <yonghong.song@linux.dev>,
	"Jiri Olsa" <jolsa@kernel.org>,
	"Emil Tsalapatis" <emil@etsalapatis.com>,
	"Ihor Solodrai" <ihor.solodrai@linux.dev>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH bpf] bpf: Fix soft lockup in fd_array_map_free()
Date: Thu, 12 Nov 2026 19:59:06 +0000	[thread overview]
Message-ID: <DMTHYMNVPCR4.1GZZE98IRO363@gmail.com> (raw)
In-Reply-To: <20261112122015.3356106-1-jinyue.li@linux.alibaba.com>

On Thu Nov 12, 2026 at 12:20 PM UTC, Li Jinyue wrote:
> fd_array_map_free() walks all map entries to assert that the map is
> empty before its memory is freed. max_entries is not bounded, and the
> free runs from the bpf_map_free_deferred work item, so with a large
> max_entries the scan occupies the CPU for a long time without a
> scheduling point:
>
>   watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [kworker/u8:5:8894]
>   Workqueue: events_unbound bpf_map_free_deferred
>    epc : fd_array_map_free+0x7c/0xea

I don't think you root caused it correctly.

pw-bot: cr



      parent reply	other threads:[~2026-11-12 19:59 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-12 12:20 [PATCH bpf] bpf: Fix soft lockup in fd_array_map_free() Li Jinyue
2026-11-12 12:30 ` sashiko-bot
2026-11-12 19:59 ` Alexei Starovoitov [this message]

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