From nobody Thu Mar 19 02:07:20 2026 Received: from mail-wr1-f49.google.com (mail-wr1-f49.google.com [209.85.221.49]) (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 75829224B0E for ; Mon, 16 Feb 2026 13:43:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.49 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771249392; cv=none; b=kqDz4K5UCIBwDXqgYRwLPMmPnAWH1hvXJlL+l34AFtvQZpUOB9B9Cw1Xtj6+W4gYrCuhEthFwtLZHplPnvTT099mkQfXn0W1dX+7m+mVgCYD0dzeKEa565NR4fFOhvnZLU5zhdWaMzIAg7R4j39nhmvH7rDkcYVF2RS8VxDFZTs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771249392; c=relaxed/simple; bh=mp3a0IiUHvP+CtGa3oJG1G5SNWHRamBAATH4Er8kLoM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JHGOKTxxB6aDcitTRJKZjkZHFgTA4nJ7Ki3IXozC+LL9Rat3s4SVUwMNt2uOwuQxwWSe9BKgH5J7oAJdZtjMMRr7zTBoFrlfRtCWnnwdfd7lXDhSEQwH0uMtPhWzBNliUj+7B7DmP3Uki7E/IbjffSAFJe2jFAFGeaGeDKUUxmQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=CxxE7Huh; arc=none smtp.client-ip=209.85.221.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="CxxE7Huh" Received: by mail-wr1-f49.google.com with SMTP id ffacd0b85a97d-43767807cf3so2365073f8f.1 for ; Mon, 16 Feb 2026 05:43:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1771249390; x=1771854190; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=5o3MpI2zvqTEg6G302fPomtVC5PLXLlOoUgfy5gbT+w=; b=CxxE7Huh/wfBF6MnJzdVtN/fclu1b/sR5SEM/qQdVoZlAwAqeRqBSEBuD6ztK1mJgI ir8+vrrbMD7QWcX4058jvtXlqh32rgjzC4XOM0toe4ZoiykpBqNnH7aS8TcfsLGAVk3+ uSQ5KyKznyoPic7t50R/e3tjhMyOjPQPu6976AA1UdpALrvGNw4IrVb8xf7kbO43Dub5 LhrMeGX33sEVqO81Xo6gs4yML/qZn50D0WPAsdl089ihLvRqs1sjx00yqKVsffMRjfw+ BgAk9lUHUZacRyBfE7eE/iuKs8SJB2OxOh7jo6RrtzjFbcuYRzahSP7UV7VAn2pXeAXW fWeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771249390; x=1771854190; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=5o3MpI2zvqTEg6G302fPomtVC5PLXLlOoUgfy5gbT+w=; b=lI3TXbeDYc7pKcKSSGPAXsjlAca19yMTVu6DclNSWlSkDkwjS1Uy/f1FCVwzlVAwSk vGEY8E9H2XxPafwjJ9egSPgZalNim3aP12jSNWpB3Gc/cV9RJ7GGN8a9xu/i4JC7ixR5 armcD6Hx6hkUtFpX5MAAkLS+W/qfiX8ia4FSR1mv2QJDJ8nLIaUF04v91ZOwX1Eh4L0g hXPMBrJuEDES8tyE1LrkAMgeQBRV/4sTFe3KpcH8nqA4rlR2jMUhpnAx3gPd9uC/NAg1 RRFGkmwtAA7wlgjfJfVDVzDG0jsDObDy4AVEj6j25X2xmMovsE3VEF9b3tQJJM95NLnK Pabw== X-Forwarded-Encrypted: i=1; AJvYcCXGNiSwBUWLE5VeXv2ZggAls83VsPa5cVNtZQU4XNydTMLNMt+kPR889fb1zs40+zWHiK3LdYHv9lM9OKA=@vger.kernel.org X-Gm-Message-State: AOJu0YzkKaaDQtu7Jy6zGLfBOJKESDmoP/VXy+vt3hPTf2PA9pYKjYxh SArZ26aODd8cM99oJyQ5Y2T41PerQU2Oim+rQzscgWltuR4Z3lIQxyNamw7g2mDvX9A= X-Gm-Gg: AZuq6aJgWvqz9l833CaQ27drOOVe0WYstzatImHp0OVTc0UlVnEtOrs2VwrVbB03xi/ EBORIfFEPUbSmNLppUOG6s0HgjT8UwGK50xSh8GwgFg28nfj5gyrsWXZTxCnv/BvDGUK5mjcQmk cWZdRq8Ue7C/XQve1eFbn26rVkaak7IqkBEWzyOLbolFrcHLHmYWUj2QDkuHzJdngHcFDmlkBhT 33bTHUFPurlfsfHQHtmTr2otjCcJBAw9qemxcAdjfSLVjpNiYh61FZdbN6ndavFYct90Mw2jGMV 3l1kssEbbUkNn6GRP/VMyJizYpwSIlkQX1MKrhGqK7drDXZ2KLfNcrKJVbNR6jiy/Ewei65Issv OH7y8CQr/j1T/zjZdSoA0ZEpulE+A4kuT3AGbbDTSTfacmZ/kFH+ZZZmjFRQSGHSjrRRo/T/y7G 50OMIGKv0ul57FGEAm+xsDYFPtiJ/doQPNG4K7RXx3 X-Received: by 2002:a05:6000:2406:b0:425:769e:515a with SMTP id ffacd0b85a97d-4379db98589mr16674501f8f.42.1771249389801; Mon, 16 Feb 2026 05:43:09 -0800 (PST) Received: from zovi.suse.cz (nat2.prg.suse.com. [195.250.132.146]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43796a6ba57sm22103738f8f.15.2026.02.16.05.43.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Feb 2026 05:43:09 -0800 (PST) From: Petr Pavlu To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , Tom Zanussi , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Petr Pavlu Subject: [PATCH v2 1/4] tracing: Fix checking of freed trace_event_file for hist files Date: Mon, 16 Feb 2026 14:41:57 +0100 Message-ID: <20260216134247.1311631-2-petr.pavlu@suse.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260216134247.1311631-1-petr.pavlu@suse.com> References: <20260216134247.1311631-1-petr.pavlu@suse.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The event_hist_open() and event_hist_poll() functions currently retrieve a trace_event_file pointer from a file struct by invoking event_file_data(), which simply returns file->f_inode->i_private. The functions then check if the pointer is NULL to determine whether the event is still valid. This approach is flawed because i_private is assigned when an eventfs inode is allocated and remains set throughout its lifetime. Instead, the code should call event_file_file(), which checks for EVENT_FILE_FL_FREED. Using the incorrect access function may result in the code potentially opening a hist file for an event that is being removed or becoming stuck while polling on this file. A related issue is that although event_hist_poll() attempts to verify whether an event file is being removed, 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 these issues by changing the access method to event_file_file() and 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. Fixes: 1bd13edbbed6 ("tracing/hist: Add poll(POLLIN) support on hist file") Signed-off-by: Petr Pavlu Acked-by: Masami Hiramatsu (Google) --- include/linux/trace_events.h | 5 +++++ kernel/trace/trace_events.c | 3 +++ kernel/trace/trace_events_hist.c | 4 ++-- 3 files changed, 10 insertions(+), 2 deletions(-) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 3690221ba3d8..f925034e402d 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -683,6 +683,11 @@ static inline void hist_poll_wakeup(void) =20 #define hist_poll_wait(file, wait) \ poll_wait(file, &hist_poll_wq, wait) + +#else +static inline void hist_poll_wakeup(void) +{ +} #endif =20 #define __TRACE_EVENT_FLAGS(name, value) \ diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 137b4d9bb116..e8ed6ba155cf 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 |=3D EVENT_FILE_FL_FREED; event_file_put(file); + + /* Wake up hist poll waiters to notice the EVENT_FILE_FL_FREED flag. */ + hist_poll_wakeup(); } =20 /* diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_h= ist.c index c97bb2fda5c0..744c2aa3d668 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5778,7 +5778,7 @@ static __poll_t event_hist_poll(struct file *file, st= ruct poll_table_struct *wai =20 guard(mutex)(&event_mutex); =20 - event_file =3D event_file_data(file); + event_file =3D event_file_file(file); if (!event_file) return EPOLLERR; =20 @@ -5816,7 +5816,7 @@ static int event_hist_open(struct inode *inode, struc= t file *file) =20 guard(mutex)(&event_mutex); =20 - event_file =3D event_file_data(file); + event_file =3D event_file_file(file); if (!event_file) { ret =3D -ENODEV; goto err; --=20 2.52.0 From nobody Thu Mar 19 02:07:20 2026 Received: from mail-wr1-f52.google.com (mail-wr1-f52.google.com [209.85.221.52]) (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 0038430E0EF for ; Mon, 16 Feb 2026 13:43:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.52 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771249394; cv=none; b=lIEPqwgOmMRj2CbYUKrlCQogmoQeZ6btz44X2TdnbX4Lg8hmfK697Q57UOt/NxLhBFHV49vk2EWAEuqGomEBgbPMVaGikmEIceiQqoyKPhZ3PwrXWKcCvdNS3oSIu32NzPYDjZHDjQB8eexYOLyOsh/3otM3p5WFliS4rVvQaM0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771249394; c=relaxed/simple; bh=KJwpMUhbsmLePIcgVFzyOrsUa+2IV8OxHWYQmxoWDOg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oZoo8fzH+yYiXZCSO64noiHHVb3fD35HbOUhfMB+I+Oq1T24hhUKNUIG1d7uSzUIE5cRL062o8IpICYtQInzN/L9blla3/LzMOaNamJ8mFPXHmCRFXjD/dUlUdrEVuRG/9dVTxGmRZudJfL5j5h2Sq4dBiKd7JWxhWcOgNSTN34= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=QOpxNdVb; arc=none smtp.client-ip=209.85.221.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="QOpxNdVb" Received: by mail-wr1-f52.google.com with SMTP id ffacd0b85a97d-43945763558so841190f8f.3 for ; Mon, 16 Feb 2026 05:43:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1771249390; x=1771854190; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=1JPwPVqvwveog74YxYE5rN1bA4FdwdVXGOb+2Uf2Xb8=; b=QOpxNdVbj8MxSnNobKMQ/91aGC1Z0kuk6juLfzjxbJQ7jq15zRmXvvsOz9t66SdBmM QfY81C4qUMiL1sI9vb6Dpr7izIrdMfWv+u7UJVqvdyyXgUxsTQICT8JsPKuXVDuekXUT xZUS/RcHm9Ok0fRpqL+XwBxe6Pme/iy6BZ3hrH6m4SwJnzmZhXFarQJ1tc7zcaV2mACV 8NXXGt5TBYlR2zaqnVG1bkTTjYXWwXa6x1aowAJc0gVgGXatKRiDir5ogQYe1hK6aY+a 5/Ry2YAk8fMR6vtS1Fm2JTgDPBR+hr8uuRjP3CLE0IHyn78LdfRw6T60QSfZgLAWMh43 NN2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771249390; x=1771854190; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=1JPwPVqvwveog74YxYE5rN1bA4FdwdVXGOb+2Uf2Xb8=; b=F67dbPngozE1cfgrf83GI6BCBmvuD1xPli7KuZc4awxZRhcYaBut42YKmyGywENUgS U/FhGfbAhZRdAqWUS57GKzo6kmTxRxotGmh+qIDJqeQ+CJ/dlLfbmnujVk6tWGMCsjqa 6P+nDQsl77KAFapufjL4ZeE7rJjUtcR/PusoAPlGn1uj0v/+6S8QRZfrXMsUFIF6m7w/ npDdw15aNu6WIBtqxUp4nKsBye6NeYSCo8SeIrl6oYjIMsxCaQGWh+8K5OWw2HIdD27J xZXb+xsJzpy7ETTy/4MxkUD8u24eP8oxOeFt0BugKwHb32LewVEZAKPD1LejcYpU76Xn AYtg== X-Forwarded-Encrypted: i=1; AJvYcCWjjMzsf5wvNFy1r8tA2zszbLmMeslgTmOmp7KhL1yZaB3tiZ9NExjJP1MzMvgEh8HlML78kvmmcvILYUc=@vger.kernel.org X-Gm-Message-State: AOJu0YzroxYtEzQAShSwXNQSABgFaKU5vOLb53qij79wzXbcRYZKI7rX tZgnuPk06JQI48pYsMVBD0PaqnQQUASwvrzrNdBmaCU4qj+0GCg0mJN8SJ0SQ7tojHc= X-Gm-Gg: AZuq6aJtnaSf5kOXOw1L2nyCvKhLcSUbog0QN4V0AnIM/BzWrNpMd3DYNXh8+FGlBtc HPI1oEPtARI7s4rb0E6TyA+HuKi1GbdWQ2jasdInv6MrCLg3MMEtWnPn4DOsBYcriGXYhqoYV9Y QjiO3cTv3+IVXXBONi8KEdYED3KvclM4nrxWmjQoG08zqECOPsB65yWUjVpBNB8/m9CZuKNuQDC pGanBzShA+bgNYUgUJMvFBQZI9mf+HbNWzuh9c0Xy5BTc5vMAGiBMuMAeNGz8bmSZqEjOQBhsNB 4C629ziRT3IGymn+bUqkTECnsMkQ4VULiDsAYCg9gpV2OqslNUjej5pFXEraF6sPcEzckteRWDH Y8Zw3kCE3S1vrO/Rr9nlRX9Qo+aspOLJKmPE/oVhknkpvrfZrJze/bLctoVr1cO/aD5VNIEQk5v dKCurPOgKOY4zuusEOi5IhXF9e3r2UDLyzJPEnjGEq X-Received: by 2002:a05:6000:2382:b0:437:719d:a740 with SMTP id ffacd0b85a97d-43796af9f04mr18671659f8f.49.1771249390407; Mon, 16 Feb 2026 05:43:10 -0800 (PST) Received: from zovi.suse.cz (nat2.prg.suse.com. [195.250.132.146]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43796a6ba57sm22103738f8f.15.2026.02.16.05.43.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Feb 2026 05:43:10 -0800 (PST) From: Petr Pavlu To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , Tom Zanussi , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Petr Pavlu Subject: [PATCH v2 2/4] tracing: Remove unnecessary check for EVENT_FILE_FL_FREED Date: Mon, 16 Feb 2026 14:41:58 +0100 Message-ID: <20260216134247.1311631-3-petr.pavlu@suse.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260216134247.1311631-1-petr.pavlu@suse.com> References: <20260216134247.1311631-1-petr.pavlu@suse.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The event_filter_write() function calls event_file_file() to retrieve a trace_event_file associated with a given file struct. If a non-NULL pointer is returned, the function then checks whether the trace_event_file instance has the EVENT_FILE_FL_FREED flag set. This check is redundant because event_file_file() already performs this validation and returns NULL if the flag is set. The err value is also already initialized to -ENODEV. Remove the unnecessary check for EVENT_FILE_FL_FREED in event_filter_write(). Signed-off-by: Petr Pavlu --- kernel/trace/trace_events.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index e8ed6ba155cf..2ca76b048638 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2153,12 +2153,8 @@ event_filter_write(struct file *filp, const char __u= ser *ubuf, size_t cnt, =20 mutex_lock(&event_mutex); file =3D event_file_file(filp); - if (file) { - if (file->flags & EVENT_FILE_FL_FREED) - err =3D -ENODEV; - else - err =3D apply_event_filter(file, buf); - } + if (file) + err =3D apply_event_filter(file, buf); mutex_unlock(&event_mutex); =20 kfree(buf); --=20 2.52.0 From nobody Thu Mar 19 02:07:20 2026 Received: from mail-wr1-f44.google.com (mail-wr1-f44.google.com [209.85.221.44]) (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 E0D2130EF67 for ; Mon, 16 Feb 2026 13:43:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.44 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771249394; cv=none; b=SVdtedl0TJchZfgzccCx8wBM77gf+JfZBIZ2Ob53CQiBPJPgFLLaxnl8Lds89Uu2qOfGUtQ/mklFrLemFUL4kwGw6EJBZ4MtEepHEo3FRYvCVZhhQZcFFDRY7CoUYoOnSpm8pomxoYwh8N7NrZwFrSg+AL5mW38Tcx3YizL1k6s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771249394; c=relaxed/simple; bh=33NvmzifiaBRigoFifMef35hi/yQkfKUWjLhPBQHZC0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ajxsP19euzxwmojjubg8vH2HaMtlJ3N5hdJuSBvA8y8OjhoGROgGkAdW8fe7fR+pcEmTFJmkD4a4gJlIseQRQMs2hmwSWKwqzRAx+jXjUxruN34jqJgey7p8mr24in4YZ5OLlyWbDZSMLqlj+OEtfgLU2VIa5eAvBf7HctsbGsE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=RKWcAa77; arc=none smtp.client-ip=209.85.221.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="RKWcAa77" Received: by mail-wr1-f44.google.com with SMTP id ffacd0b85a97d-435a11957f6so2730231f8f.0 for ; Mon, 16 Feb 2026 05:43:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1771249391; x=1771854191; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=BHlgJV/WzhgeNXBdeNtIIZu+ZwNnn+yQBr5wKMb7lyM=; b=RKWcAa77lpb10O5MnDtr5VaK7M6v25kfM9ifJhCHx/7fBjPQO87Qc6xrXFuxjSO3f+ wsCWew92zoMGSxMlvjxps5ZbkHswZneiITzk0N8grriSOf6L3okS3Qd72aDW6vXpOtUo iWJXi+QfuyFoZM1G7i375PNfZElfGmDHJJqbeZIojB1xaVhry7vRJijG8c81UINhTkLE nDRvarjv6a56Rrv4ol1UZ9s+mPdTjJC1mCoI+3kTbu3cyk72Cjm1DQ5jkAfhM6iu1YNC aE4riU+Lsv3rPDvX4eIAL3mdnINALPasf5oNO6uxYiCMGIcBilCsd3xzSsZeqMC0SXLd sqcQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771249391; x=1771854191; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=BHlgJV/WzhgeNXBdeNtIIZu+ZwNnn+yQBr5wKMb7lyM=; b=JT0z7HqUeCs+p7HLhujg3Dz03mudn6Dj43i3TWQzoxtZRi7D63EZKxo8aoWaz1rYk4 VQik2jtQoX0qu/HGi1N9Dmq8tfa7wcE52PM2ayvwp3NH0ysJu9gKnt7agPZeg0JLMgbM TiVn1W6tjM9k1mlCzJ589mkmunb4bwzv0ePmGaSdfHdLvSftXD0JPBI/TlFogPwalcfU msmTl8xxfRYe3LVd/2bP7WCAWmq9qcY8Oqgg1u+YkPIUa+hWAY+4hhGPKxAbkr2k/kJt VOtz8uL3xZpyrZreSLA4U1FkDH8ZnHSHDVopMeqpdE4ZqqrtiRn7TZe9viOa8EzQk6EK ExSg== X-Forwarded-Encrypted: i=1; AJvYcCVH4UN0bG/OVHsSPTKJ4dD1+C8fBpjL3FjXnyooUBEN0VQ0VMD5jaGp7XY4GGJDkjVGVyz/7obsY8gbuFQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yx3gsadJRTjaoypeXIXaDZ7jBspCDYhcKH+f7MBJHt9T+eUlc8x C7bR/uGn9ROVzT2j0cl8njrL6oJUTIoCtHsw2Z7Gz6p56wMIdtfGD/ve6SJ+b2KSE4o= X-Gm-Gg: AZuq6aJ90AWrxCbURQKZ05FE6G8nocJ7jzurl6/kfJvXKICVGIZLbYWNcZ7PVhGGe/g XWRZdx6NF8LeZLE7Wk5O7OGHLaY5SPujx9skOlseOEK0+v2jC27zCQMahw1jF1xmOgp0KYq4vrs Z14tcwvEWCS1luT6E26oUS5LXxeS3F1ZzYirJ4A0T19ng7nB7bcOFUxPXCs2fhMdKKwbowrR6pU RwFTs45T3u5HlFLP+wXasJt65Utotv4Ck20Sfq1S89pZZEis7soQNDeER+XDL2GCk8aGX290YPI 28m/RZLAPUpRz0zHpfXIkWSO3Gf6oawulhZ9cIFv5pZHaeYg7gfYN/GcnMXXt7IeDuKtXdbeBXN 4VcZ6wOuLTjJ+jByAw37AVUlKaArZLPYvyHudcU1chtUobRke68iIkedWgdYAjUvZlZL+TFSyJ1 uwWXx9MJaJCZG6ZTdoR6Z9nzI2yZupAGt5hxpWZH+bTR2dSDatDPM= X-Received: by 2002:a05:6000:2481:b0:436:8058:45a with SMTP id ffacd0b85a97d-43797913eaamr17300323f8f.39.1771249391215; Mon, 16 Feb 2026 05:43:11 -0800 (PST) Received: from zovi.suse.cz (nat2.prg.suse.com. [195.250.132.146]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43796a6ba57sm22103738f8f.15.2026.02.16.05.43.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Feb 2026 05:43:10 -0800 (PST) From: Petr Pavlu To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , Tom Zanussi , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Petr Pavlu Subject: [PATCH v2 3/4] tracing: Clean up access to trace_event_file from a file pointer Date: Mon, 16 Feb 2026 14:41:59 +0100 Message-ID: <20260216134247.1311631-4-petr.pavlu@suse.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260216134247.1311631-1-petr.pavlu@suse.com> References: <20260216134247.1311631-1-petr.pavlu@suse.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The tracing code provides two functions event_file_file() and event_file_data() to obtain a trace_event_file pointer from a file struct. The primary method to use is event_file_file(), as it checks for the EVENT_FILE_FL_FREED flag to determine whether the event is being removed. The second function event_file_data() is an optimization for retrieving the same data when the event_mutex is still held. In the past, when removing an event directory in remove_event_file_dir(), the code set i_private to NULL for all event files and readers were expected to check for this state to recognize that the event is being removed. In the case of event_id_read(), the value was read using event_file_data() without acquiring the event_mutex. This required event_file_data() to use READ_ONCE() when retrieving the i_private data. With the introduction of eventfs, i_private is assigned when an eventfs inode is allocated and remains set throughout its lifetime. Remove the now unnecessary READ_ONCE() access to i_private in both event_file_file() and event_file_data(). Inline the access to i_private in remove_event_file_dir(), which allows event_file_data() to handle i_private solely as a trace_event_file pointer. Add a check in event_file_data() to ensure that the event_mutex is held and that file->flags doesn't have the EVENT_FILE_FL_FREED flag set. Finally, move event_file_data() immediately after event_file_code() since the latter provides a comment explaining how both functions should be used together. Signed-off-by: Petr Pavlu --- kernel/trace/trace.h | 17 +++++++++++------ kernel/trace/trace_events.c | 6 +++--- 2 files changed, 14 insertions(+), 9 deletions(-) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 8428c437cb9d..27fb3fe6a7e0 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1739,11 +1739,6 @@ extern struct trace_event_file *find_event_file(stru= ct trace_array *tr, const char *system, const char *event); =20 -static inline void *event_file_data(struct file *filp) -{ - return READ_ONCE(file_inode(filp)->i_private); -} - extern struct mutex event_mutex; extern struct list_head ftrace_events; =20 @@ -1764,12 +1759,22 @@ static inline struct trace_event_file *event_file_f= ile(struct file *filp) struct trace_event_file *file; =20 lockdep_assert_held(&event_mutex); - file =3D READ_ONCE(file_inode(filp)->i_private); + file =3D file_inode(filp)->i_private; if (!file || file->flags & EVENT_FILE_FL_FREED) return NULL; return file; } =20 +static inline void *event_file_data(struct file *filp) +{ + struct trace_event_file *file; + + lockdep_assert_held(&event_mutex); + file =3D file_inode(filp)->i_private; + WARN_ON(!file || file->flags & EVENT_FILE_FL_FREED); + return file; +} + extern const struct file_operations event_trigger_fops; extern const struct file_operations event_hist_fops; extern const struct file_operations event_hist_debug_fops; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 2ca76b048638..d23e7a9d07e6 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2090,12 +2090,12 @@ static int trace_format_open(struct inode *inode, s= truct file *file) static ssize_t event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *pp= os) { - int id =3D (long)event_file_data(filp); + /* id is directly in i_private and available for inode's lifetime. */ + int id =3D (long)file_inode(filp)->i_private; char buf[32]; int len; =20 - if (unlikely(!id)) - return -ENODEV; + WARN_ON(!id); =20 len =3D sprintf(buf, "%d\n", id); =20 --=20 2.52.0 From nobody Thu Mar 19 02:07:20 2026 Received: from mail-wr1-f44.google.com (mail-wr1-f44.google.com [209.85.221.44]) (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 7578430EF9A for ; Mon, 16 Feb 2026 13:43:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.44 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771249394; cv=none; b=B6gF63VKCJ2SJRS6MaSMpI4Oc1QMNL1/b18ALW/u89enAZ7UfXByK5EwWiOfxZSWICQTSwqEGQoHEBWSA7K2V60sDI4Im+Ky89ePlfjoS8tclaNXO4W0AwSJtc24730sfXtiDbHTL2Zand1VK4FkXZbF4nnXwHLLdWU6FE26KF0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771249394; c=relaxed/simple; bh=d+Vle/naWPS7QzNS2FVGa4vf3BGBMNuu7Vbe2EcZcxo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=vEtcbK87I5Y/G7Eicd4h17YH5Kn7oeR7J4QXfkjzv7wyfZtzC/Q230nbKrIBYViJFlBzNt+yEWjQMjCVkpAe328kdfwXpq0GZ+O1SR1GTFeHu79jrGowjR5mApONeAdgYWIuuVET/k23sxseAHanYO8lqgzG277CQiQBgthW0gg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=S12IrLME; arc=none smtp.client-ip=209.85.221.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="S12IrLME" Received: by mail-wr1-f44.google.com with SMTP id ffacd0b85a97d-4362507f396so3101188f8f.0 for ; Mon, 16 Feb 2026 05:43:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1771249392; x=1771854192; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=dtEMv4P3LsYt3Vtm/NRXERllJMmTHuXEYSzyDVKCmoo=; b=S12IrLMEgwx4DcyOIE42BKM0gtdhi0KBI6iZmbGEhykAEFRyBUwsGENIuayfZwwOKF DPtwFDVT1yxk9xP9q+wdTevGdgUPcmssbOI+MWfrtpI99A4+pHCFbTMzKMZmkUQT/enw JLYvSYt2DbnGE6d4ZM9iDvXN3y8qIPSMFf/e37XCt6K7N/IElNwIvp91RlqTHx8befSP 7mO0jDSJHqTXYuQLYZQBhmLkYB23Du/No6inuTnhZjOaYUrP+cTqSir4nWuWc2pAjSeO lRlkhR/NYmd5MMWuSGaSg+boc6Jy++VUYzuroTOF9EJdXezheJ64ZmTr6eYp+lFFc9Rn 8xRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771249392; x=1771854192; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=dtEMv4P3LsYt3Vtm/NRXERllJMmTHuXEYSzyDVKCmoo=; b=L3f9fCYc9271+jSq05fYyFB5RlZKK9E1l+BbyDDHxjkKwkMeD9hVaodhC7DEQnZmQh 9eyMvssKjABR8p+WRlOonotQVfGexk6ATNCNHA0GcqxTsZTY1vgcKKxposvjy85UXzIC rrPHwqiQyuM3i1DHl/ng7iTOEaGtbiCEBD+aiEAGU+TaoTAx5eCgRPCb7xnBOW7B7BNr mYdadZa4zGUwf7tlEbZg+2TbH4A4Vb49d2Wo1aGT3pPrpf1o1eR+XVNJ3i7sFPsMeK0O CDsanZZPyNvv5oLV3xfqCCyEhhxCSTnLncXGwdJ3cyQ8Hmtp8FxFoMmDzbFSqDSvxwG1 9VAw== X-Forwarded-Encrypted: i=1; AJvYcCX/DKv63Wk3aviIBNQ/qt4dP5Ru9saQ1YYBwXmfaBQZksTUM18A7ybuPmfmTQwifR5tOcCsqpdujKC0CIQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yxzi8LAmw20FGsNAIcYxF7q3WlLG64wH/9hLITyv6O679YYIr/C CBWXu3IGt8nrMOs12Ol99n327eNW4TYSLssVitLIbQHkB/ctfcbBXcRQ4B/joCQwBDE= X-Gm-Gg: AZuq6aIHDQbXJXUgwli/SSjvvojiA6xoQXS7YfSiPQ+zFLOXTz02fmHeSu2InF9j1Nv +KcXd7LdT10qFpoKd/ao+rZrK7gH61S6I/VQvFUz16/zlQIOjlREwu9CiiI88PY6/o9cReJfYGV xZbFvgzcbKfRqX1lB9PxH0gmlBQZDUhFK6zP50FB8+5JSxoAZEtyISnnBjMzrc8hvhHqygNYKTc 9IKFfPc1Mmnars9DZySAnwKjjDa+j/kq0KxCgKxdEkgvR2rY0oNNVqUMVFaWSBf+qvpy6Syh2B/ Ejpu0BLMsjhEOFYgPipB7LDPCLDdG8j1ue5EyyRXdg9NO8AbD3YyjyjKziPmowsGCZqJrQWzIHY p5EV6PaRmMiJvXdtik2gJIQsG+Fg+R3lvbd4EQFRKP1CkiSDFv3Crx47MFLmkamlKIjP36VJICW ZMa+9UcP9eAHnUfYwZndLdokrSbz925e/hpEk8aWgy X-Received: by 2002:a5d:5d88:0:b0:436:d9b:cd02 with SMTP id ffacd0b85a97d-43797851769mr15744120f8f.0.1771249391830; Mon, 16 Feb 2026 05:43:11 -0800 (PST) Received: from zovi.suse.cz (nat2.prg.suse.com. [195.250.132.146]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43796a6ba57sm22103738f8f.15.2026.02.16.05.43.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Feb 2026 05:43:11 -0800 (PST) From: Petr Pavlu To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , Tom Zanussi , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Petr Pavlu Subject: [PATCH v2 4/4] tracing: Free up file->private_data for use by individual events Date: Mon, 16 Feb 2026 14:42:00 +0100 Message-ID: <20260216134247.1311631-5-petr.pavlu@suse.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260216134247.1311631-1-petr.pavlu@suse.com> References: <20260216134247.1311631-1-petr.pavlu@suse.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The tracing_open_file_tr() function currently copies the trace_event_file pointer from inode->i_private to file->private_data when the file is successfully opened. This duplication is not particularly useful, as all event code should utilize event_file_file() or event_file_data() to retrieve a trace_event_file pointer from a file struct and these access functions read file->f_inode->i_private. Moreover, this setup requires the code for opening hist files to explicitly clear file->private_data before calling single_open(), since this function expects the private_data member to be set to NULL and uses it to store a pointer to a seq_file. Remove the unnecessary setting of file->private_data in tracing_open_file_tr() and simplify the hist code. Signed-off-by: Petr Pavlu --- kernel/trace/trace.c | 2 -- kernel/trace/trace_events_hist.c | 4 ---- 2 files changed, 6 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b1cb30a7b83d..01af8d88a468 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4804,8 +4804,6 @@ int tracing_open_file_tr(struct inode *inode, struct = file *filp) event_file_get(file); } =20 - filp->private_data =3D inode->i_private; - return 0; } =20 diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_h= ist.c index 744c2aa3d668..1ca3e14d7531 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5831,8 +5831,6 @@ static int event_hist_open(struct inode *inode, struc= t file *file) hist_file->file =3D file; hist_file->last_act =3D get_hist_hit_count(event_file); =20 - /* Clear private_data to avoid warning in single_open() */ - file->private_data =3D NULL; ret =3D single_open(file, hist_show, hist_file); if (ret) { kfree(hist_file); @@ -6114,8 +6112,6 @@ static int event_hist_debug_open(struct inode *inode,= struct file *file) if (ret) return ret; =20 - /* Clear private_data to avoid warning in single_open() */ - file->private_data =3D NULL; ret =3D single_open(file, hist_debug_show, file); if (ret) tracing_release_file_tr(inode, file); --=20 2.52.0