From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2219A42D964; Sat, 28 Feb 2026 17:46:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300807; cv=none; b=QVryTY55L8JrBgwi4lxG+qnkGC9El4c3BQvA5UFLSDgq6mXJGnuRmbbz00Zn9FSiJUCmGqsWSH3UG8fdu0EPlm0RvZDBBRxD8V7y1f6ZPnY7vvNVLFGY4Qb/c1OlKjAQXCMSoMEwA0Qw2XzuR55yGkcWAcW5YnBXyp6TxMfFCoQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300807; c=relaxed/simple; bh=AmLdO0QPKnhH6ZGLu6FlqBEAVfRFCPeqGx5cMIZlodw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=umLJiixN/6goZC67O8RYC0Q9NZEP7AOGyg2ER7Lfags+ULIJLsTfLOddmeC0xfsNZFp0LV/uhtbAMATaTXXuGI3os2AwkPE0ylJwZMC6TvEHQ0MeBZewcLqsbFjZl1Bk5ZcewL5uo58e4KvLlpTSQr7ch9fUoZecRj706dT/s74= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TG3iifcC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TG3iifcC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A8AAC116D0; Sat, 28 Feb 2026 17:46:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772300807; bh=AmLdO0QPKnhH6ZGLu6FlqBEAVfRFCPeqGx5cMIZlodw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TG3iifcCQGCJW7QZL7BsvLcuNJNV+ln7rG3iDiIIj8t9pRPL7f0e7lmCr7bDZXaOR iN20GUqvXOTzP6FnHDdaw0bKFZKXgKkXwSQs+GWRHjTRyiLHEHyV53pGkhC2mf8jJt 2b398RSm+WO+pUfsfMv5Ufg1nXpsFXouWQz1N+euejJsw6zuXZ47e9QMBzxU8jsLUB tEyJsHFrlQs7du6gDu64uNYpD3aKsE8elV3yM5ymQ0dWt0EQcfhR2SzJqwzbZ+QDVg acJW+bnSgLkBfSce4s27F6UTFddZmnBLDg4n/MkYUjzGui4VevwaTIM4KyqA90+Kv0 Cko7C87C82aXA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Petr Pavlu , Mathieu Desnoyers , Tom Zanussi , "Masami Hiramatsu (Google)" , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.19 839/844] tracing: Wake up poll waiters for hist files when removing an event Date: Sat, 28 Feb 2026 12:32:32 -0500 Message-ID: <20260228173244.1509663-840-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228173244.1509663-1-sashal@kernel.org> References: <20260228173244.1509663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Petr Pavlu [ Upstream commit 9678e53179aa7e907360f5b5b275769008a69b80 ] The event_hist_poll() function attempts to verify whether an event file is being removed, but this check may not occur or could be unnecessarily delayed. This happens because hist_poll_wakeup() is currently invoked only from event_hist_trigger() when a hist command is triggered. If the event file is being removed, no associated hist command will be triggered and a waiter will be woken up only after an unrelated hist command is triggered. Fix the issue by adding a call to hist_poll_wakeup() in remove_event_file_dir() after setting the EVENT_FILE_FL_FREED flag. This ensures that a task polling on a hist file is woken up and receives EPOLLERR. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers Cc: Tom Zanussi Acked-by: Masami Hiramatsu (Google) Link: https://patch.msgid.link/20260219162737.314231-3-petr.pavlu@suse.com Fixes: 1bd13edbbed6 ("tracing/hist: Add poll(POLLIN) support on hist file") Signed-off-by: Petr Pavlu Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- include/linux/trace_events.h | 5 +++++ kernel/trace/trace_events.c | 3 +++ 2 files changed, 8 insertions(+) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 3690221ba3d80..f925034e402dc 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -683,6 +683,11 @@ static inline void hist_poll_wakeup(void) #define hist_poll_wait(file, wait) \ poll_wait(file, &hist_poll_wq, wait) + +#else +static inline void hist_poll_wakeup(void) +{ +} #endif #define __TRACE_EVENT_FLAGS(name, value) \ diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 2c6d3e33b9fb4..ec66170637102 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1295,6 +1295,9 @@ static void remove_event_file_dir(struct trace_event_file *file) free_event_filter(file->filter); file->flags |= EVENT_FILE_FL_FREED; event_file_put(file); + + /* Wake up hist poll waiters to notice the EVENT_FILE_FL_FREED flag. */ + hist_poll_wakeup(); } /* -- 2.51.0