From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09DA9C74A5B for ; Thu, 23 Mar 2023 19:31:12 +0000 (UTC) Received: from mail-pg1-f171.google.com (mail-pg1-f171.google.com [209.85.215.171]) by mx.groups.io with SMTP id smtpd.web11.82703.1679599865971476227 for ; Thu, 23 Mar 2023 12:31:06 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@gmail.com header.s=20210112 header.b=dNIko4YS; spf=pass (domain: gmail.com, ip: 209.85.215.171, mailfrom: theflamefire89@gmail.com) Received: by mail-pg1-f171.google.com with SMTP id x37so13226215pga.1 for ; Thu, 23 Mar 2023 12:31:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1679599865; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=SGGUP66K1KV+FHjsn5qlN49/pkRCncbVQZDsDyYvwJ8=; b=dNIko4YSGK9vQMaHc/5MV9Nn6w1/4tAqnl3SxWok3D6M3qfjhVZd8tOIC4u94k4AmB Aor2jItLFanpxuC4ZSdM/m8q47cttqRScySMbZTcz4kyZRhBTJYXfO42jiQ9VX1B3b30 1/quSl7K6hg3+TOZTvXfRMXHi43gutrz+RjH/VBdiQJOLllXFM+BDNC6/pUHJKMHI6ft FdtGVxGTvTiMqw0dGDQ25RN6yKlKVTaq6i6VL8rSBq+51i2euRs+KAQJ/GRs3Yr5v1wF 4zh0gVkUmo2aBAHkJwQ3+Z3Riqz3C57e0S2443Ej07+Q+0R1YPMfek6tfTMETvKkSC18 rZgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679599865; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=SGGUP66K1KV+FHjsn5qlN49/pkRCncbVQZDsDyYvwJ8=; b=MXuNHrnlcXXYhydBRrp28ZreOV8wx8guGmqgXSFldjGNXRPY5E7olByY7B0q6Oxkzo pELjphmeaybKQZ5byXMxLtMift3s59ptbnCMXJb+aMav8Ll6Rms7XTXowDjJqTRUt69Q KDWpmOjWy7t2rBokOf1tbTiW+nP+Qe5x4aLog+Tsh7fhfhGKf46nE+oqpz55+6Fws7jo GEOQ/OPheQ2hsV+qVNM0UNtCL1CBHGaCYQ4QKXgAdRRHrEmjFCMeUTMjTBiSNTl7aEf6 lPzZo2q6zEnig8MuSLhotBZ2L07DNxqUKVbc5FDttRAJPK4NgqE8/gQf/dehSie65Hli 9Fig== X-Gm-Message-State: AO0yUKVR7s1pCY2eFWf9EMSxddu7n0i/6ESYCVRUc4ciSvRMVRyVfTik pv50v/FCEqb9bLW5EAE+M3Jo1oybpoZbtgdo3F1/eKRtoTo= X-Google-Smtp-Source: AK7set96b5dGg49y5hGDV5eXUHPF9IaKM4j21xPof247BSfRDFdvxQ+b1W1dSXJWbjwvNIsdfG4nWCUzeaFfstbFsCY= X-Received: by 2002:a65:420c:0:b0:50a:592b:25ba with SMTP id c12-20020a65420c000000b0050a592b25bamr2243237pgq.3.1679599865280; Thu, 23 Mar 2023 12:31:05 -0700 (PDT) MIME-Version: 1.0 From: Alexander Grund Date: Thu, 23 Mar 2023 20:30:54 +0100 Message-ID: Subject: ALSA: pcm: Broken commit in v4.4-st38 To: cip-dev@lists.cip-project.org Content-Type: text/plain; charset="UTF-8" List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Thu, 23 Mar 2023 19:31:12 -0000 X-Groupsio-URL: https://lists.cip-project.org/g/cip-dev/message/11103 Hi, I found a bug in v4.4-st38 caused by e8064dec769e6e0822e179107d0b5b3d2e03e181 "ALSA: pcm: Move rwsem lock inside snd_ctl_elem_read to prevent UAF" 1) It introduces down_read/up_read around a call to snd_ctl_elem_read however that is superflous: snd_ctl_elem_read already does that, so the commit 56b88b50565c referenced by the above is already included 2) down_write/up_write around snd_ctl_elem_write causes a deadlock because snd_ctl_elem_write does a down_read at the start. The latter is probably (another) bug likely caused by missing upstream commit becf9e5d553c2389d857a3c178ce80fdb34a02e1 "ALSA: control: code refactoring for ELEM_READ/ELEM_WRITE operations " which removes that lock. Maybe that should be included here too, it also removes the locking in snd_ctl_elem_read which means 1) is no longer superflous Best, Alexander Grund