From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BCB8A17993 for ; Thu, 20 Aug 2026 20:02:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787256140; cv=none; b=qtqMcpTttxwRddhQ7g21lTlqvKqzNBQpI8FV8gUtVeXTDRFtGpQgFuUSjZly5K36ur2bIyMwXfKNaGRk1UhklKiWaDlERrfI5jbntFXsycuQBzQftLSpofPlY3l5D8jCbnYdQ8FfzpVWBKc/bpSSGnIGmDM7fAFfyyTJtWOE9v4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787256140; c=relaxed/simple; bh=dPRqJ1mlI/IFPCa4Sqq8ARYfgBmSkgzc8GLRzlDzPGg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Q8tTHlnF5thu0rNlx5aeiIvskDY387VA5yadHKro2aYzXu/gx5vOi97dF7ZlIIwvo5U/f/7FOPbyiTls42fLBRSpF8MlgL2+gPSlZGGJjEvq7PyJYErbD0JpMgUH1ftp0x3XHFQlCHemmY5zDrT1A+9INfwKjoGpYq9LIvBY2ag= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=X8ey2x31; arc=none smtp.client-ip=209.85.215.198 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="X8ey2x31" Received: by mail-pg1-f198.google.com with SMTP id 41be03b00d2f7-cbee57593baso145294a12.3 for ; Thu, 20 Aug 2026 13:02:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787256138; x=1787860938; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=naPXrGNP/ZZPz03m+r90wYcO4W6hJGOcA9yVDHAeuqc=; b=X8ey2x3189enMqJlVBcbyoLQOQ6Mt5QPAOeQAIQOIL/CzopMpOw5QMAHLwwKcEdW/y ESNLP6CZV6Qn9PHyU8D+qOkPU6ZHXrw2TR3JPu5lXElBJ9z7FGlpq8K6CMW90AM3Y0OM AkLlAuViCJsTraQ7qvanQhEklTgqPRKuYdMQizCvNAj37UPV3Dc1h0Jx6IG6NYeBKx8k T/UtIUPb4XkEpF2mnp83df4qzxzTRm7LrOTvAICto3BefhoR+IKsfRRyT+lm6twhsXXd wTrgB6TktzG0HJ2UT7g9+OMCzXhEDqkCpNBVEhgTzlU0v886CSBrv6LEQ+/TklMBWWRl XE9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787256138; x=1787860938; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=naPXrGNP/ZZPz03m+r90wYcO4W6hJGOcA9yVDHAeuqc=; b=fZniBNj2At3oViMTiUDlca/C+UapXs6BUYJ7nCmCGTDI7Esu/vouEmdvTrA66bQRMs TbgQIlA5hzffYevQeicB+Mp6slgf3drSMTLSPiF5Ey46A5BJS5U+StofZ9jB45R6EK8Q iOJSig7xn/eX4NFVhMJ4slQ/BabnKTeF05fQs7B4sgzySiK0GWoKe9ELC1JJr/CaBcOT TORJwiGYc1Z18tXO7sWi8UQhT6lbIZxzPpbrpb9/wC55tGEpfEzrn5c9zBpOq1aRy3fj UgQ5Ov/uT/tY6Ix5az2lISJqzXHjoUiOpRhyA196TmkOzlv4hQxd3a6tfa/xih6ysqSd 9OZg== X-Forwarded-Encrypted: i=1; AHgh+Rr/hSnWNrGEJb25hcopOe7VRbyBTEGj/18ylzlrCgL3htV+tliyaDDkYKu6PWEba5hItabhlt+63AdcjQPrUa03@vger.kernel.org X-Gm-Message-State: AOJu0YwzzOykxXaHlg4v8OpWmrXddgdB5cqP6F+rlhFuBCdsEl6IbzsT K3Q6c8EtQl/up2UiSHfTxF4zhFPOqDlkRqFWKVWLPZ04HtTb/Tr6Av7W288apDK2VL+5+oGchAU p/wjScnAdLQ== X-Received: from dycqw25-n2.prod.google.com ([2002:a05:7300:c019:20b0:313:b34f:8861]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:1fc8:b0:3cc:9316:cad3 with SMTP id adf61e73a8af0-3cd2fa367c0mr2107577637.0.1787256137872; Thu, 20 Aug 2026 13:02:17 -0700 (PDT) Date: Thu, 20 Aug 2026 13:02:14 -0700 In-Reply-To: <20260820164937.2734066-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260820164937.2734066-1-irogers@google.com> X-Mailer: git-send-email 2.55.0.766.g2966f0265a-goog Message-ID: <20260820200214.2865570-1-irogers@google.com> Subject: [PATCH v7] perf record: Fix unhandled POLLHUP on non_perf_event descriptors From: Ian Rogers To: irogers@google.com, acme@kernel.org, namhyung@kernel.org Cc: abyssmystery@gmail.com, adrian.hunter@intel.com, james.clark@linaro.org, jolsa@kernel.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, mingo@redhat.com, peterz@infradead.org Content-Type: text/plain; charset="UTF-8" When processing POLLHUP on a non_perf_event control descriptor, evlist__finalize_ctlfd() is invoked to finalize the setup, correctly setting the core evlist's poll array file descriptor to -1. However, this finalized teardown state is never propagated back to the individual thread's local replica of the pollfd array. Consequently, on the next iteration of the main recording loop, record__update_evlist_pollfd_from_thread() performs a strict equivalence check between the core evlist's array and the thread's localized poll array, detecting that the fd values no longer match. This causes an immediate -EINVAL abort and a premature teardown. Fix the underlying logic within record__update_evlist_pollfd_from_thread() to sustainably propagate the finalized teardown statuses (-1) originating from the core evlist back to the thread's localized poll structure. This correctly maintains synchronization and entirely prevents the unhandled index mismatch crashes. Additionally, add a unit test that explicitly validates that fdarray__filter() preserves its invariants regarding fdarray_flag__nonfilterable items to guard against regressions. Fixes: fb4751e79c45 ("perf record: Fix teardown hang on system-wide multi-threaded sessions") Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Ian Rogers --- tools/perf/builtin-record.c | 15 +++++++++++++++ tools/perf/tests/fdarray.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 47 insertions(+) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index a57987851cf0..ad81458989b5 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1169,6 +1169,21 @@ static int record__update_evlist_pollfd_from_thread(struct record *rec, int e_pos = rec->index_map[i].evlist_pollfd_index; int t_pos = rec->index_map[i].thread_pollfd_index; + if (e_entries[e_pos].fd == -1 || e_entries[e_pos].events == 0) { + /* + * If the control file descriptor was closed, then evlist__ctlfd_process() + * will have called evlist__finalize_ctlfd() on the PREVIOUS loop iteration + * to cleanly set the core evlist's e_entries[e_pos].fd to -1. + * + * Since nonfilterable items are skipped by fdarray__filter(), the + * thread's local t_entries[t_pos] retains its original state. + * We must explicitly propagate the finalized -1 state to t_entries + * BEFORE evaluating the strict equivalence check below. + */ + t_entries[t_pos].fd = -1; + t_entries[t_pos].events = 0; + } + if (e_entries[e_pos].fd != t_entries[t_pos].fd || e_entries[e_pos].events != t_entries[t_pos].events) { pr_err("Thread and evlist pollfd index mismatch\n"); diff --git a/tools/perf/tests/fdarray.c b/tools/perf/tests/fdarray.c index 40983c3574b1..23860edb8ef0 100644 --- a/tools/perf/tests/fdarray.c +++ b/tools/perf/tests/fdarray.c @@ -80,6 +80,38 @@ static int test__fdarray__filter(struct test_suite *test __maybe_unused, int sub goto out_delete; } + fdarray__init_revents(fda, POLLHUP); + fda->priv[2].flags = fdarray_flag__nonfilterable; + + pr_debug("\nfiltering all but fda->entries[2] (nonfilterable):"); + fdarray__fprintf_prefix(fda, "before", stderr); + + /* + * Note: fdarray__filter() in tools/lib/api/fd/array.c evaluates the + * fdarray_flag__nonfilterable flag at the very top of its loop via an + * early continue. Therefore, it completely skips all processing for this + * descriptor, guaranteeing its fd, events, and revents fields remain + * entirely untouched by the filter mask evaluation below it. + */ + nr_fds = fdarray__filter(fda, POLLHUP, NULL, NULL); + fdarray__fprintf_prefix(fda, " after", stderr); + + if (nr_fds != 0) { + pr_debug("\nfdarray__filter()=%d != 0, should be 0\n", + nr_fds); + goto out_delete; + } + if (fda->entries[2].fd == -1) { + pr_debug("\nfdarray__filter() illegally modified nonfilterable fd!"); + goto out_delete; + } + if (fda->entries[2].revents != POLLHUP) { + pr_debug("\nfdarray__filter() illegally modified nonfilterable revents!"); + goto out_delete; + } + + fda->priv[2].flags = 0; /* reset flags */ + pr_debug("\n"); err = 0; -- 2.55.0.766.g2966f0265a-goog