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 E8E0B2E041A for ; Sat, 27 Sep 2025 11:52:56 +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=1758973978; cv=none; b=cM1rKjSLyRXZXqQXiAzBPFiExhnGDwqAtI/z0ksl1x123fk2j73etUjQJGzka2nRaQ1zzejnH2lthMeO6apb3+DW+KaULIgGbxj37zcc/leZOBArSBwd0yY++vWG82DktatoWHw89MkP4McXlSira3/ccP1red8Vc6z5fdqFuhk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758973978; c=relaxed/simple; bh=3Qh5rLSTawxJRSctDgGgAJWu6GbOYmKl1Kvx15urDEs=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=POM5ocRGnzHvmpJHXvmFL4MOcOWM/Qn5aqv0q3MmA24AxbPQP+0DM7bICTT2zlrdvQHGdWCLWAG06TvH0GebD5sbK9/noWmZI8gQuwT17F1zf+5bj3D2YyoobAvffORu8zhj+m4lAdMR16vAvjkawksuj3Z6NMlODDdsC8aQr90= 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=Ikph7uHd; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=B0Gd+6rQ; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=mgKnZQBq; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=FI8Ea9qU; 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="Ikph7uHd"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="B0Gd+6rQ"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="mgKnZQBq"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="FI8Ea9qU" 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 EED9937223; Sat, 27 Sep 2025 11:52:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1758973975; 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=VIIe7BVxo3nW2jr+S7icNHFFH4p89eeOK8EoRY7eKmE=; b=Ikph7uHdCEhi1Jb8+n70qo6WQ/DrKs0Xgj3mQps9aiF7Yexb8XgTswaT35Lt8o/BSGghZq Gv+9oDTSsfG5/RoKpPMTt0/X61bxoknt/TyuoqlLdPlGCMOgRUghki35tMjgJh7IuU2Tb/ KWzRRzMLylxMmYJ3MtOgZyRcS6PV79c= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1758973975; 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=VIIe7BVxo3nW2jr+S7icNHFFH4p89eeOK8EoRY7eKmE=; b=B0Gd+6rQXjdJimQ7J7D7FDwKV0bfRORWG/0PnddfjMcTu/QtjT6xHJmgXPuGLeZL3vBxy+ qRtxeT9rBDF9joBQ== Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=mgKnZQBq; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=FI8Ea9qU DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1758973973; 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=VIIe7BVxo3nW2jr+S7icNHFFH4p89eeOK8EoRY7eKmE=; b=mgKnZQBqqJj69doxHHE6UiJh5fYSjld4tnFhc28PuG9dELEsLs8w7PVQDLq5nfQM9ex0Sb gKipVWE30pZXmfGD99EAK+KZl2zD1bilY10RsTSF0CWt+wS7vtGQb91/fyBiiP2gTWhrSs K3bNleS9T28wgovh9/jp4ZmJR5ZqMXI= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1758973973; 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=VIIe7BVxo3nW2jr+S7icNHFFH4p89eeOK8EoRY7eKmE=; b=FI8Ea9qUeTJnwik8RVitAtUIsCIvSgiHl+EVsFuXO5fuwwZdjOniIqnJod+EFHdFTUAeMg d9F9D56Z9q40RdAQ== 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 A84021373E; Sat, 27 Sep 2025 11:52:53 +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 RB9VJxXQ12gOcgAAD6G6ig (envelope-from ); Sat, 27 Sep 2025 11:52:53 +0000 Date: Sat, 27 Sep 2025 13:52:53 +0200 Message-ID: <87o6qw9koa.wl-tiwai@suse.de> From: Takashi Iwai To: Jeongjun Park Cc: syzbot , clemens@ladisch.de, hdanton@sina.com, linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org, perex@perex.cz, syzkaller-bugs@googlegroups.com, tiwai@suse.de Subject: Re: [syzbot] [sound?] [usb?] general protection fault in snd_usbmidi_do_output In-Reply-To: References: <20250927091931.7691-1-hdanton@sina.com> <68d7b657.a70a0220.10c4b.000e.GAE@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 Precedence: bulk X-Mailing-List: linux-kernel@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-Spam-Level: X-Spam-Flag: NO X-Rspamd-Queue-Id: EED9937223 X-Rspamd-Action: no action X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spamd-Result: default: False [-2.01 / 50.00]; BAYES_HAM(-3.00)[99.99%]; SUSPICIOUS_RECIPS(1.50)[]; 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)[]; FREEMAIL_TO(0.00)[gmail.com]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FREEMAIL_ENVRCPT(0.00)[gmail.com,sina.com]; RCVD_TLS_ALL(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,suse.de:mid]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[syzkaller.appspotmail.com,ladisch.de,sina.com,vger.kernel.org,perex.cz,googlegroups.com,suse.de]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:106:10:150:64:167:received,2a07:de40:b281:104:10:150:64:97:from]; TAGGED_RCPT(0.00)[f02665daa2abeef4a947]; RCPT_COUNT_SEVEN(0.00)[9]; DKIM_TRACE(0.00)[suse.de:+]; RCVD_VIA_SMTP_AUTH(0.00)[]; SUBJECT_HAS_QUESTION(0.00)[] X-Spam-Score: -2.01 On Sat, 27 Sep 2025 12:36:07 +0200, Jeongjun Park wrote: > > syzbot wrote: > > > > Hello, > > > > syzbot has tested the proposed patch but the reproducer is still triggering an issue: > > KASAN: slab-use-after-free Write in snd_usbmidi_in_urb_complete > > > > ================================================================== > > BUG: KASAN: slab-use-after-free in snd_usbmidi_in_urb_complete+0x389/0x3c0 sound/usb/midi.c:251 > > Write of size 1 at addr ffff888074717943 by task kworker/1:3/5866 > > > > Wow, the UAF bug still occurs? > > But... this UAF seems to be a problem with how midi handles urb rather > than a problem with my patch. > > Is there something wrong with the way snd_usbmidi_in_urb_complete() is > implemented? This can be rather a missing kill-and-cleanup in the code path. So the patch like below. Could you check whether this works for you instead of your fix, too? timer_shutdown_sync() is already called in snd_usbmidi_disconnect(), and the call in snd_usbmidi_free() should be superfluous after this change. thanks, Takashi --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -1522,6 +1522,9 @@ static void snd_usbmidi_free(struct snd_usb_midi *umidi) { int i; + if (!umidi->disconnected) + snd_usbmidi_disconnect(&umidi->list); + for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) { struct snd_usb_midi_endpoint *ep = &umidi->endpoints[i]; if (ep->out)