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Tue, 28 Jan 2025 22:23:50 -0800 (PST) Message-ID: Date: Wed, 29 Jan 2025 14:23:42 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Re: [PATCH bpf v2] bpf: Fix deadlock when freeing cgroup storage Content-Language: en-US To: Martin KaFai Lau , Alexei Starovoitov Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , David Vernet , "open list:BPF [STORAGE & CGROUPS]" , open list References: <20241221061018.37717-1-wuyun.abel@bytedance.com> <02c69185-1477-485c-af4f-a46f7aadadab@linux.dev> <7139ed64-55be-4b70-a03f-8b2414fc93d3@bytedance.com> <3c153542-079a-4566-9f32-8335bbb0456a@linux.dev> From: Abel Wu In-Reply-To: <3c153542-079a-4566-9f32-8335bbb0456a@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 1/28/25 7:05 AM, Martin KaFai Lau Wrote: > On 1/27/25 2:15 PM, Alexei Starovoitov wrote: >> On Sun, Jan 26, 2025 at 1:31 AM Abel Wu wrote: >>> >>> On 1/25/25 4:20 AM, Martin KaFai Lau Wrote: >>>> >>>> imo, that should be a better option instead of having more unnecessary failures in all other normal use cases which will not be interested in tracing cgroup_storage_ptr(). >> >> Martin, >> >> task_storage_map_free() is doing this busy inc/dec already, >> in that sense doing the same in cgroup_storage_map_free() fits. > > sgtm. Agree to be consistent with the task_storage_map_free. > > would be nice if the busy inc/dec usage can be revisited after the rqspinlock work. Agree, and 1ms interval of deadlock dection seems acceptable for most workloads. > > Acked-by: Martin KaFai Lau Thanks Alexei, Martin.