From nobody Sun Dec 14 13:44:41 2025 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (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 EC16422E409 for ; Thu, 16 Jan 2025 19:41:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737056482; cv=none; b=phaIt0uS5/pc6dXUQYuMHiFNXZsDDVIRTjMB6wMEwW/yj5XZ5t0WFudr154IPj3IiiKX26df128GEchHKTOXGGGtDfAlU+/Gw6QUcg2zazGBRnuFeLk/Ikk5nE+Ca2OEUCPSN4fLD247greaqraYwfc3oGJKCTlyp66wCGRj/z0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737056482; c=relaxed/simple; bh=9teq+JaoUOCCJi8v76Xn+Iblh9s5emNTyUVHhpT+Amc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=g/Z/LY/5UQpiIbhblPCZVIx9jUWvQTGtZyP8xf+SR/S5T8K/J16/RovBX2hlsF6VAmMV0YI3Ay/mJ+5gEjQTuHfoOCoJXagVq/PeSqwUQpmARD3rxrI4H+C2Vo1Wet68umYfKE1dMmnn4/8B/JGLeS5hBU2TVDel6Q7dQxxNq8k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=HANtayAE; arc=none smtp.client-ip=209.85.216.74 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--jstultz.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="HANtayAE" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-2ef9e38b0cfso2708509a91.0 for ; Thu, 16 Jan 2025 11:41:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1737056480; x=1737661280; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=9c+mKdS6UvxTM+mMX7MZ1E/vU8+YRkTBKKT8mptdijw=; b=HANtayAEJeoH0SSrKKVHHmgf94Du++CeyorgZYqE0Eq5XPe9LEZpIJR2HbC6w5QFrx V4nDcKQoutYma5KMLcsdbzw5r3wUzBJxwce+1Rwn2BJEaREkfX1fM8/hTq6SPi3Zs1YA Nrz0TWfiQ/MRSAb0mgE6oA7sSlVUosJPBS76niV93/aNy36GOhTAh5jOWDBp0N1ug38r R8moy+ibaGQWLHLzZIl66ymdHoCak7uJbnlM396MlzpctwLKAepWoYr8c3OKtUkDwRYk Vesi0QNB8cYwZ8dpHECfXNdt0q1OBLbOCtH1ekg3Ajr2udDW+Foh2srkWowTNdJnCHrS tg3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1737056480; x=1737661280; h=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; bh=9c+mKdS6UvxTM+mMX7MZ1E/vU8+YRkTBKKT8mptdijw=; b=BIlHOKVqNYy1imiceTNo/Yzeo/c0nmVduDi+3tddY6JyGh4hGc7fgW6RGhHMrJlrBm YM/aoh9tU4s0L+uyVoCKMKLDL5Su9bqJS4Y8kANwkrnJxLUxx0dEMkTtW98EvLum7wyT UeN5d46kqWb7fr78HSv8DCad3EYJBrtW+v2CPiDRVvjZRs3xmNA+skTFazNi3dr7jFoE kwfnpW2fwKIgjd3WA1CZIsJNwZXPWw4UuSUkp84EV7t70uMT9vYEXCJ8BRS7RbONb5a5 Ms61CDKpHejFZcv8sltpZbH+4dztoo5Ij5IDBDkfi9QEtakRknmC3rJ3McVmQS8cmahc PcYw== X-Gm-Message-State: AOJu0Yy1XXWoBuT27aYHUI0nKzEoahK5E84M0c0WKuU/iVC3OnsSPORy nQr9Ae0d7T635Hmo/qeuAmydj5fJKhZKZ2EpiiV83UdmnWz3Hrkmd4GZfuR8obCp5AFT7NgOw8a fzDsEPFzfXXDZSlVHzNYvPLYsXaqmyACOr2I1kBVCucEgnHt5lj6wFZyovgP5/fn7Z/Fji7HfVW tcrTVH7iEN2Y855jVIXn6JLo0xYMUvZjvyCiHOvtA4bqU3 X-Google-Smtp-Source: AGHT+IHAxCEfJhjinmdp7iL+RcQHMoAkeF1j+7nASLrBvD6x6xTr0/mXwbpnY2YoABTiPpn8G6D6/jrHd328 X-Received: from pjbsn6.prod.google.com ([2002:a17:90b:2e86:b0:2ea:4139:e72d]) (user=jstultz job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:258c:b0:2ee:f687:6ad5 with SMTP id 98e67ed59e1d1-2f548ea5b95mr51110210a91.2.1737056480195; Thu, 16 Jan 2025 11:41:20 -0800 (PST) Date: Thu, 16 Jan 2025 11:40:59 -0800 In-Reply-To: <87ed12j20b.wl-tiwai@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <87ed12j20b.wl-tiwai@suse.de> X-Mailer: git-send-email 2.48.0.rc2.279.g1de40edade-goog Message-ID: <20250116194114.3375616-1-jstultz@google.com> Subject: [PATCH v2] sound/virtio: Fix cancel_sync warnings on uninitialized work_structs From: John Stultz To: LKML Cc: John Stultz , Anton Yakovlev , "Michael S. Tsirkin" , Jaroslav Kysela , Takashi Iwai , virtualization@lists.linux.dev, linux-sound@vger.kernel.org, kernel-team@android.com, Betty Zhou , Takashi Iwai Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Betty reported hitting the following warning: [ 8.709131][ T221] WARNING: CPU: 2 PID: 221 at kernel/workqueue.c:4182 ... [ 8.713282][ T221] Call trace: [ 8.713365][ T221] __flush_work+0x8d0/0x914 [ 8.713468][ T221] __cancel_work_sync+0xac/0xfc [ 8.713570][ T221] cancel_work_sync+0x24/0x34 [ 8.713667][ T221] virtsnd_remove+0xa8/0xf8 [virtio_snd ab15f34d0dd772= f6d11327e08a81d46dc9c36276] [ 8.713868][ T221] virtsnd_probe+0x48c/0x664 [virtio_snd ab15f34d0dd77= 2f6d11327e08a81d46dc9c36276] [ 8.714035][ T221] virtio_dev_probe+0x28c/0x390 [ 8.714139][ T221] really_probe+0x1bc/0x4c8 ... It seems we're hitting the error path in virtsnd_probe(), which triggers a virtsnd_remove() which iterates over the substreams calling cancel_work_sync() on the elapsed_period work_struct. Looking at the code, from earlier in: virtsnd_probe()->virtsnd_build_devs()->virtsnd_pcm_parse_cfg() We set snd->nsubstreams, allocate the snd->substreams, and if we then hit an error on the info allocation or something in virtsnd_ctl_query_info() fails, we will exit without having initialized the elapsed_period work_struct. When that error path unwinds we then call virtsnd_remove() which as long as the substreams array is allocated, will iterate through calling cancel_work_sync() on the uninitialized work struct hitting this warning. Takashi Iwai suggested this fix, which initializes the substreams structure right after allocation, so that if we hit the error paths we avoid trying to cleanup uninitialized data. Note: I have not yet managed to reproduce the issue myself, so this patch has had limited testing. Feedback or thoughts would be appreciated! Cc: Anton Yakovlev Cc: "Michael S. Tsirkin" Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: virtualization@lists.linux.dev Cc: linux-sound@vger.kernel.org Cc: kernel-team@android.com Reported-by: Betty Zhou Suggested-by: Takashi Iwai Signed-off-by: John Stultz --- v2: Use Takashi Iwai's suggested approach --- sound/virtio/virtio_pcm.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/sound/virtio/virtio_pcm.c b/sound/virtio/virtio_pcm.c index 967e4c45be9b..2f7c5e709f07 100644 --- a/sound/virtio/virtio_pcm.c +++ b/sound/virtio/virtio_pcm.c @@ -339,6 +339,21 @@ int virtsnd_pcm_parse_cfg(struct virtio_snd *snd) if (!snd->substreams) return -ENOMEM; =20 + /* + * Initialize critical substream fields early in case we hit an + * error path and end up trying to clean up uninitialized structures + * elsewhere. + */ + for (i =3D 0; i < snd->nsubstreams; ++i) { + struct virtio_pcm_substream *vss =3D &snd->substreams[i]; + + vss->snd =3D snd; + vss->sid =3D i; + INIT_WORK(&vss->elapsed_period, virtsnd_pcm_period_elapsed); + init_waitqueue_head(&vss->msg_empty); + spin_lock_init(&vss->lock); + } + info =3D kcalloc(snd->nsubstreams, sizeof(*info), GFP_KERNEL); if (!info) return -ENOMEM; @@ -352,12 +367,6 @@ int virtsnd_pcm_parse_cfg(struct virtio_snd *snd) struct virtio_pcm_substream *vss =3D &snd->substreams[i]; struct virtio_pcm *vpcm; =20 - vss->snd =3D snd; - vss->sid =3D i; - INIT_WORK(&vss->elapsed_period, virtsnd_pcm_period_elapsed); - init_waitqueue_head(&vss->msg_empty); - spin_lock_init(&vss->lock); - rc =3D virtsnd_pcm_build_hw(vss, &info[i]); if (rc) goto on_exit; --=20 2.48.0.rc2.279.g1de40edade-goog