From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, adobriyan@gmail.com,
shakeel.butt@linux.dev, hannes@cmpxchg.org, ak@linux.intel.com,
osandov@osandov.com, song@kernel.org, jannh@google.com,
linux-fsdevel@vger.kernel.org, willy@infradead.org,
Eduard Zingerman <eddyz87@gmail.com>
Subject: Re: [PATCH v7 bpf-next 09/10] bpf: wire up sleepable bpf_get_stack() and bpf_get_task_stack() helpers
Date: Mon, 11 Nov 2024 14:51:46 +0900 [thread overview]
Message-ID: <20241111055146.GA1458936@google.com> (raw)
In-Reply-To: <20240829174232.3133883-10-andrii@kernel.org>
Hi,
On (24/08/29 10:42), Andrii Nakryiko wrote:
> Now that build ID related internals in kernel/bpf/stackmap.c can be used
> both in sleepable and non-sleepable contexts, we need to add additional
> rcu_read_lock()/rcu_read_unlock() protection around fetching
> perf_callchain_entry, but with the refactoring in previous commit it's
> now pretty straightforward. We make sure to do rcu_read_unlock (in
> sleepable mode only) right before stack_map_get_build_id_offset() call
> which can sleep. By that time we don't have any more use of
> perf_callchain_entry.
Shouldn't this be backported to stable kernels? It seems that those still
do suspicious-RCU deference:
__bpf_get_stack()
get_perf_callchain()
perf_callchain_user()
perf_get_guest_cbs()
next prev parent reply other threads:[~2024-11-11 5:51 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-29 17:42 [PATCH v7 bpf-next 00/10] Harden and extend ELF build ID parsing logic Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 01/10] lib/buildid: harden " Andrii Nakryiko
2024-11-01 13:54 ` Jiri Olsa
2024-11-01 18:12 ` Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 02/10] lib/buildid: add single folio-based file reader abstraction Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 03/10] lib/buildid: take into account e_phoff when fetching program headers Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 04/10] lib/buildid: remove single-page limit for PHDR search Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 05/10] lib/buildid: rename build_id_parse() into build_id_parse_nofault() Andrii Nakryiko
2024-10-14 2:50 ` Lai, Yi
2024-10-14 23:41 ` Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 06/10] lib/buildid: implement sleepable build_id_parse() API Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 07/10] lib/buildid: don't limit .note.gnu.build-id to the first page in ELF Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 08/10] bpf: decouple stack_map_get_build_id_offset() from perf_callchain_entry Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 09/10] bpf: wire up sleepable bpf_get_stack() and bpf_get_task_stack() helpers Andrii Nakryiko
2024-11-11 5:51 ` Sergey Senozhatsky [this message]
2024-11-11 17:49 ` Andrii Nakryiko
2024-11-12 1:29 ` Sergey Senozhatsky
2024-11-13 20:40 ` Andrii Nakryiko
2024-08-29 17:42 ` [PATCH v7 bpf-next 10/10] selftests/bpf: add build ID tests Andrii Nakryiko
2024-09-03 22:38 ` [PATCH v7 bpf-next 00/10] Harden and extend ELF build ID parsing logic Andrii Nakryiko
2024-09-11 0:27 ` Alexei Starovoitov
2024-09-11 17:10 ` patchwork-bot+netdevbpf
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