From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sipsolutions.net (s3.sipsolutions.net [168.119.38.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A41B306B0D; Fri, 24 Oct 2025 08:39:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=168.119.38.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761295187; cv=none; b=d5F3zYZFEHu02fnOMqw0xN6qyXqNQdunXHyJu371/NUbD/AsbUCFY93NLhW0623+mKYXRw9XWyElbLmZeFPGbg+wSZzW4tdlknt32lZjXAhu3yHDtorJuI3qbRxEH8wWuJro73TSowvmboFWSfVz9FTaJHeUWFWCWRXBiqzbL6c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761295187; c=relaxed/simple; bh=0jFenninAF/hgduw9GfWU0HOuF4au/RFUfhZZruyXsI=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=HVFiiW57C+Ie+aabP+PAgNdsYKAGjf8CoadJQcVLOCieyr4xECW2x5jHZ4Y9knkp1tF30/TxHHQ8Gd75sfcNK/YqVsskUimP2yjMYn8AP/+D4PjFlYYIkh9Igc1gl2OAwcHTyv8WwP0ZyJmdC3nGGeyPL124QEi/zODPLxTdCq0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net; spf=pass smtp.mailfrom=sipsolutions.net; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b=krvNaJbb; arc=none smtp.client-ip=168.119.38.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b="krvNaJbb" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=2cMlx6dBNBmuoC08wN2ZIHtm4MB/TmlTbPKY6RErk4M=; t=1761295186; x=1762504786; b=krvNaJbbmSFgtM6XZGmhKbQPgyCu2IQ8sT9rNiTTpp4x0As ixCtI7HysVETY/E4Lvli0wEljlavlv7FEnDlxckOCIm9ZSfrXqxaBPGalX5RyU/XHJWPNo5QV/CpU QpHIpOQdTZRARjj0p8nvO5B7C/AkaCp7T1OS5tV+b4e66XSlKC1Z7IjARcNVSweYDoEXMnAxfvdP5 2x1SS8OmBR8jYoJr/YgEGfdJ0gvesBKgVXVMRKUG0IxVgUHUgpRG16v+l/Us/jFoYHDzXrUVR9sXt ApHcJL4w0U3UrOlVeokeXEuKOIGZivH0P4ajvLc6DsER3r/G/a0/ZnoveSzSaj4w==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.98.2) (envelope-from ) id 1vCDKm-00000002PRW-3W1T; Fri, 24 Oct 2025 10:39:41 +0200 Message-ID: <247568f47e1955be454e951e80a9063123f97c66.camel@sipsolutions.net> Subject: Re: [PATCH] devcoredump: Fix circular locking dependency with devcd->mutex. From: Johannes Berg To: Maarten Lankhorst , linux-kernel@vger.kernel.org Cc: intel-xe@lists.freedesktop.org, Mukesh Ojha , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , stable@vger.kernel.org, Matthew Brost Date: Fri, 24 Oct 2025 10:39:39 +0200 In-Reply-To: References: <20250723142416.1020423-1-dev@lankhorst.se> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-malware-bazaar: not-scanned On Fri, 2025-10-24 at 10:37 +0200, Maarten Lankhorst wrote: > >=20 > > CPU 0 CPU 1 > >=20 > > dev_coredump_put() devcd_del() > > -> devcd_free() > > -> locked > > -> !deleted > > -> __devcd_del() > > -> __devcd_del() > >=20 > > no? > >=20 > > johannes >=20 >=20 > Yeah don't you love the races in the design? All intricate and subtle. :) > In this case it's handled by disable_delayed_work_sync(), > which waits for devcd_del() to be completed. devcd_del is called from the= workqueue, > and the first step devcd_free does is calling disable_delayed_work_sync, = which means > devcd_del() either fully completed or was not run at all. Oh... right, I totally missed the _sync. My bad, sorry. I guess I really should say Reviewed-by: Johannes Berg since I finally _did_ review it carefully. Sorry it took forever. johannes