From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (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 B07BA3009D6 for ; Fri, 10 Apr 2026 06:31:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775802689; cv=none; b=C0YUvpsqlrlb/OTYJjrfhjcVnGTuPiGn6Uqa67mejgzfYWj1kRs7eLKqsS9cy0b2+w3s58zmVx7PhC8Sf33k4a1O00Q7CzabiWwP8inggSrHzkAE0mW3JIvsPrnBPAUfBgvYoKvb4KdLzS+p86YhbPEW36s4gbS7j06uvJSMo70= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775802689; c=relaxed/simple; bh=QLe0m0hoz3rd/qnbfOlhgcbrwRWCGtZDq/B4xaL38Zs=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=gX8GCblHb6p9LdibSDplAg9CV3FVAKw87gEasNnOugTRzMeisg/gVd/UjuW5Lmy1nooAtZuyBfEdltnLmLjICuDDiGqVHxlIu114ZPO85C3uepiiJ5kWrZCvrCtPN2ijkEC2y1OJ3tSejTi/zA5Z08Waab/xTTKDA4tjztmcVmk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=zWmhhb8U; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=w7ZzHNYb; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=Hk+JKPfy; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=KIXoJDmV; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="zWmhhb8U"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="w7ZzHNYb"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="Hk+JKPfy"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="KIXoJDmV" Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id D04CF6A7DF; Fri, 10 Apr 2026 06:31:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1775802685; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=COOB62QyGZwwQRplwoeshvKVJc2tDlOH8vwe004NBGE=; b=zWmhhb8U/T2jfiWQnJEOCvLvoyLY1MIY7W0aMy4W1licVTzNP+98PycoTT9XDNnQs+LXK9 WX9c2rbnDQ/d3nMj9zuOAydw0LLx/BOJDipIHhYt7KDWzBtWGLO+TrzLt2nqKgQDtH9w3P idzB1vvskRSJCyuFIcdtAQSIqmQihCw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1775802685; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=COOB62QyGZwwQRplwoeshvKVJc2tDlOH8vwe004NBGE=; b=w7ZzHNYbv93rfcJ+d6fCJe7z/QCr14muDoJErUiqpkp9O3jZYXcaM1UTfCkFjeHVYNW6Gg FryZahuVl7X04WCQ== Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=Hk+JKPfy; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=KIXoJDmV DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1775802684; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=COOB62QyGZwwQRplwoeshvKVJc2tDlOH8vwe004NBGE=; b=Hk+JKPfyoelr2NFUleCIEEy9Zfyp+jl2PDOLpzodwrqaBZSfHRELBwvI2ug0kqcD5mnWr2 FMIq4F/MYTDvL0ipZeKDTTJ/ekhwu0tQABAQyHjljVZKCQ0vuqbB9CgFm1veIpGslaideH 8mnDtafoODM86X/2hedeUs8LRSBqMkA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1775802684; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=COOB62QyGZwwQRplwoeshvKVJc2tDlOH8vwe004NBGE=; b=KIXoJDmV1hT7ysl5sf4UkAmPp0l0CZtaHb7jgHjUB9UYU99peRMdM4MyeSRLQthByc5XHq DAe31aZkmuEyibAw== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 97AA24A0B2; Fri, 10 Apr 2026 06:31:24 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id A3a3IzyZ2Gk/EAAAD6G6ig (envelope-from ); Fri, 10 Apr 2026 06:31:24 +0000 Date: Fri, 10 Apr 2026 08:31:24 +0200 Message-ID: <87tstjgwcj.wl-tiwai@suse.de> From: Takashi Iwai To: Berk Cem Goksel Cc: Takashi Iwai , Jaroslav Kysela , linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, Andrey Konovalov , stable@vger.kernel.org Subject: Re: [PATCH 2/2] ALSA: caiaq: take a reference on the USB device in create_card() In-Reply-To: <20260410045904.1064020-3-berkcgoksel@gmail.com> References: <20260410045904.1064020-1-berkcgoksel@gmail.com> <20260410045904.1064020-3-berkcgoksel@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/30.2 Mule/6.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-Rspamd-Action: no action X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Spamd-Result: default: False [-3.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; MID_CONTAINS_FROM(1.00)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_TLS_ALL(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_TO(0.00)[gmail.com]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[suse.com,perex.cz,vger.kernel.org,gmail.com]; RCPT_COUNT_SEVEN(0.00)[7]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns,suse.de:dkim,suse.de:mid]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DKIM_TRACE(0.00)[suse.de:+] X-Rspamd-Queue-Id: D04CF6A7DF X-Spam-Flag: NO X-Spam-Score: -3.51 X-Spam-Level: On Fri, 10 Apr 2026 06:59:04 +0200, Berk Cem Goksel wrote: > > The caiaq driver stores a pointer to the parent USB device in > cdev->chip.dev but never takes a reference on it. The card's > private_free callback, snd_usb_caiaq_card_free(), can run > asynchronously via snd_card_free_when_closed() after the USB > device has already been disconnected and freed, so any access to > cdev->chip.dev in that path dereferences a freed usb_device. > > On top of the refcounting issue, the current card_free implementation > calls usb_reset_device(cdev->chip.dev). A reset in a free callback > is inappropriate: the device is going away, the call takes the > device lock in a teardown context, and the reset races with the > disconnect path that the callback is already cleaning up after. > > Take a reference on the USB device in create_card() with > usb_get_dev(), drop it with usb_put_dev() in the free callback, > and remove the usb_reset_device() call. > > Fixes: 523f1dce7096 ("ALSA: snd-usb-caiaq: add support for NI Audio Kontrol 1") > Cc: stable@vger.kernel.org > Cc: Andrey Konovalov > Signed-off-by: Berk Cem Goksel > --- > sound/usb/caiaq/device.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c > --- a/sound/usb/caiaq/device.c > +++ b/sound/usb/caiaq/device.c > @@ -385,7 +385,8 @@ > snd_usb_caiaq_input_free(cdev); > #endif > snd_usb_caiaq_audio_free(cdev); > - usb_reset_device(cdev->chip.dev); > + if (cdev->chip.dev) > + usb_put_dev(cdev->chip.dev); usb_put_dev() itself has a NULL check, so you can pass as is, too. And, the Fixes tag is incorrect in this patch, too. thanks, Takashi > } > > static int create_card(struct usb_device *usb_dev, > @@ -411,7 +412,7 @@ > return err; > > cdev = caiaqdev(card); > - cdev->chip.dev = usb_dev; > + cdev->chip.dev = usb_get_dev(usb_dev); > cdev->chip.card = card; > cdev->chip.usb_id = USB_ID(le16_to_cpu(usb_dev->descriptor.idVendor), > le16_to_cpu(usb_dev->descriptor.idProduct));