From: Oleg Nesterov <oleg@redhat.com>
To: Breno Leitao <leitao@debian.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
James Clark <james.clark@linaro.org>,
Andrii Nakryiko <andrii@kernel.org>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-perf-users@vger.kernel.org, kernel-team@meta.com,
stable@vger.kernel.org
Subject: Re: [PATCH] uprobes: fix incorrect lockdep condition in filter_chain()
Date: Wed, 28 Jan 2026 14:50:48 +0100 [thread overview]
Message-ID: <aXoUOEhDfncEkC-f@redhat.com> (raw)
In-Reply-To: <20260128-uprobe_rcu-v1-1-d41316763799@debian.org>
On 01/28, Breno Leitao wrote:
>
> The list_for_each_entry_rcu() in filter_chain() uses
> rcu_read_lock_trace_held() as the lockdep condition, but the function
> holds consumer_rwsem, not the RCU trace lock.
>
> This gives me the following output when running with some locking debug
> option enabled:
>
> kernel/events/uprobes.c:1141 RCU-list traversed in non-reader section!!
> filter_chain
> register_for_each_vma
> uprobe_unregister_nosync
> __probe_event_disable
>
> Remove the incorrect lockdep condition since the rwsem provides
> sufficient protection for the list traversal.
I hope Andrii will recheck, but looks obviously correct to me.
> Fixes: 87195a1ee332a ("uprobes: switch to RCU Tasks Trace flavor for better performance")
This commit just change the __list_check_rcu() condition...
Perhaps
Fixes: cc01bd044e6a ("uprobes: travers uprobe's consumer list locklessly under SRCU protection")
makes more sense?
Acked-by: Oleg Nesterov <oleg@redhat.com>
next prev parent reply other threads:[~2026-01-28 13:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-28 9:58 [PATCH] uprobes: fix incorrect lockdep condition in filter_chain() Breno Leitao
2026-01-28 13:50 ` Oleg Nesterov [this message]
2026-01-28 17:23 ` Andrii Nakryiko
2026-01-28 17:51 ` Breno Leitao
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