From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) (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 AA84335959; Sun, 29 Jun 2025 04:28:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.227.17.21 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751171284; cv=none; b=hjj0coWKblO1bOJot+f7/SSnRAR8laH+6++kVvvM5TOtWqDHaW/fHp/wImRMKdZXYAYqkIHOkYy9S79Lt7vAJB5x9JyNuuuDJNphk6XTUo5bZcvSfzmyf09rhuGf/9NpUxfzyNWUD4X0wPjMLUmodFPFvWWPgG/ddXjVJzlo2jI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751171284; c=relaxed/simple; bh=xlu3cnujlA5I8uT1VZHLLgAKcBgDbqVlHFxE9NBmNAc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kwI6DBagipKEDjS5VfoBbIzOFmJHSeWB7Vqz8hxAhOZyzm2Jm2UFDqXg8CDP3KZ+k7FC+Fotm6rEGSZlRaVzZKWLoukl7Ij7zYuvldRwCulXRpfftq/uU8ixgMugVBKAl1TmDEkEEWtvDm/zqlZjqH2lBVjIPzdth+u+CDXGYr4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gmx.com; spf=pass smtp.mailfrom=gmx.com; dkim=pass (2048-bit key) header.d=gmx.com header.i=quwenruo.btrfs@gmx.com header.b=XszsB1BX; arc=none smtp.client-ip=212.227.17.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gmx.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmx.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmx.com header.i=quwenruo.btrfs@gmx.com header.b="XszsB1BX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmx.com; s=s31663417; t=1751171270; x=1751776070; i=quwenruo.btrfs@gmx.com; bh=tW7y9mJ3/umhJnddrynSQLOYCyDsh3iqD4iQ3oex8Zc=; h=X-UI-Sender-Class:Message-ID:Date:MIME-Version:Subject:To:Cc: References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding:cc:content-transfer-encoding: content-type:date:from:message-id:mime-version:reply-to:subject: to; b=XszsB1BXu0nI8UB/5MRUZhB/gJ1Sg0YZuZvY8iEjYTP12RTnj/cgWY+ncz4uy0ew h4SNbOCieHlOpXnDA9sXpWGskP1mPrGoWYDnqdMLK9RrWMLOlNn0GpmJTuXHipM6d RJQHfEcXNojSJYimv7z23lW6yF8AQL9AE0FWiRnbO8Cg71Z0qP9Ht1RSNpkoTLt2c 88xPCmddyQ9wp2cG6TcvnUFCXlQ7ZT4pippDsr5iOE1IovMf+nmj7jj5FXXdnO1tD XhxuCphQDH+oIJC2L55p64QYct2KZDM5hMiSfQtpmc/5yqKriwlRtkzyv921zacmU yz5zWlwHeKKBA8AmAg== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from [172.16.0.229] ([159.196.52.54]) by mail.gmx.net (mrgmx104 [212.227.17.174]) with ESMTPSA (Nemesis) id 1M26vB-1uYDgS1SRN-00CXuB; Sun, 29 Jun 2025 06:27:49 +0200 Message-ID: <9e589f47-3fa2-4479-b809-5c1b91e7356f@gmx.com> Date: Sun, 29 Jun 2025 13:57:43 +0930 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH next] btrfs: fix deadlock in btrfs_read_chunk_tree To: Hillf Danton Cc: Edward Adam Davis , syzbot+fa90fcaa28f5cd4b1fc1@syzkaller.appspotmail.com, clm@fb.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com References: <685aa401.050a0220.2303ee.0009.GAE@google.com> <20250624235635.1661-1-hdanton@sina.com> <20250625124052.1778-1-hdanton@sina.com> <20250625234420.1798-1-hdanton@sina.com> Content-Language: en-US From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNIlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT7CwJQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCZxF1YAUJEP5a sQAKCRDCPZHzoSX+qF+mB/9gXu9C3BV0omDZBDWevJHxpWpOwQ8DxZEbk9b9LcrQlWdhFhyn xi+l5lRziV9ZGyYXp7N35a9t7GQJndMCFUWYoEa+1NCuxDs6bslfrCaGEGG/+wd6oIPb85xo naxnQ+SQtYLUFbU77WkUPaaIU8hH2BAfn9ZSDX9lIxheQE8ZYGGmo4wYpnN7/hSXALD7+oun tZljjGNT1o+/B8WVZtw/YZuCuHgZeaFdhcV2jsz7+iGb+LsqzHuznrXqbyUQgQT9kn8ZYFNW 7tf+LNxXuwedzRag4fxtR+5GVvJ41Oh/eygp8VqiMAtnFYaSlb9sjia1Mh+m+OBFeuXjgGlG VvQFzsBNBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAHCwHwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCZxF1gQUJEP5a0gAK CRDCPZHzoSX+qHGpB/kB8A7M7KGL5qzat+jBRoLwB0Y3Zax0QWuANVdZM3eJDlKJKJ4HKzjo B2Pcn4JXL2apSan2uJftaMbNQbwotvabLXkE7cPpnppnBq7iovmBw++/d8zQjLQLWInQ5kNq Vmi36kmq8o5c0f97QVjMryHlmSlEZ2Wwc1kURAe4lsRG2dNeAd4CAqmTw0cMIrR6R/Dpt3ma +8oGXJOmwWuDFKNV4G2XLKcghqrtcRf2zAGNogg3KulCykHHripG3kPKsb7fYVcSQtlt5R6v HZStaZBzw4PcDiaAF3pPDBd+0fIKS6BlpeNRSFG94RYrt84Qw77JWDOAZsyNfEIEE0J6LSR/ In-Reply-To: <20250625234420.1798-1-hdanton@sina.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:ZskNDeUdzrHqq3xbanMrHYXgWR++lQ52xbEiDidw6Yg0SAVUXvy /CAqdCqHETo48aYYr2/luY1l2qShblz0XeMdsQ6q8F+8yvBA22piOYtssZ6tVeE3tLQom/i NeWCOI49D+6BjA0+2xY+IsC7UxwTpOGnRtIvEF1o+7SqaVOD+0XqkasPstIw3IW65YHc1zL xVZOIBp+9qthWST81JGDw== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:1eZvRjvMO6Y=;ZypaJieInlyWaWznT6PMzFHlH/Z aWi2gyjrwONxdXLAEvgnjjk0nZ5bOlfcltWRcGW2+AjuL+KeRibWlEjcLS8Wq5WAblHYQKMCV 4kV3kk4y/sOaZAgmAtl4VgYd85VUouueKLnrybWxTToy5JBlCGmWwWvZHdwEOvjbQu3QSuYyY T7O4ov2OWr/c0LhM4JEA/SYfVtIy/09PLvjcLaYoIGB1WaA4aetRe8FQwZ0psfxCF6tOWrAUo dMnYQrgfSWhxGFiRJ1cYLux50D5+rTKtxoce9qLPgDvQB0UglcVUhQW2xpbgbpHASv3KcrbRA hyrR9u1Q91ZEhzaUEnKWlZzjr5X84vHkFMQ6RayLQ+2R3FqsB3pvHzR3KKeE1so4A3Hxopq70 tStrHHatKjBLMKwmt892Tm1McQkOn8mX+ejXA4jqY/VYmmMkL8t6lqlNt/UL4U+bINY0rjzA0 Pgl0K9+CZoZvinhzK3lPYLoRwAX6+5vtC5GNodp4IG6xGWownOvnfQGyAUce1tDVzBui4EwBg MWUcS2GYKvgKu2rXwwQ//szwBPR0SITvQire0V3MOnpOQEboyLcv0Qbi9iBAE3VbG3icfVdhG I7nc9i2X/gH/lQQx06WEFFGkDArUe4fZPd3yCunOtSCPM0YmQYGKHA1QcXMadBBwn+IVm5iJO J9T/Em8+jA/mPhOCYbV87PSzgMGQ0ZTeVpiJ6mHmdFfB5LofbKYKqiTQF986bAGt/+AAASlC4 FNRJAYt6KFZYNAgRjlyPUyHP7mrN7Rbx4AqcPTlpaNzrBGM0Mx3r41cOq/czPx0/shj2G6BrJ eJfx+iDff0526hcoL0yeZYpz8LEhgVNPV5wwYVcE0a/HvCG/uJEULKz20Aiv38aP7GGpACV6G NY0xeoVgFHGmdulGt/NbL47YEMhLvtu+qJNfXNSoxpWMAemqIxujVPONnnodGPtP7Z9SvIPzS Obp6VBsZHyiDl5hiwnLfPh1DgCbW1TUeF0NDujzPrJ0RFgc7eSrC8yPVp2PGonb4gIgoqBMbh 45PjQ5KzWnkvZA+uK5fMZfCEry8+DSw82b9apQ5soecC8RaFm8uKhMthF5bdF7V/uLDH+ZPZK 9y7hEuo3yBvDpjU8ZHB1sKMYAoAFhzETKPJBg+vX6LhoGB+233LJZw4H6aXgLDBGZHj17jVip j/jmSP3yvVmvyV3oBQnnYy6bwnrqDcTaokoFCttwPTglEe/C7QU4Au04jkSuN6T0G5wDNfQsO CpGvy5mBJ7uCcx+qDbPI1KLnr9oWzMmE2KhRMpTi1kQPT3Avg4wUO13oAQkfASI7GJ+E/ayQe DM68EBd4UI7I73JoXs9CMdUlOG+KQEdTM69PlnnipMaS3YuXI7jombtyXte1YkiFd/czqKKD4 PScEuo28nmuDDpDVAVw5nj7pIkA52GLoZWVSOo2ZRJz7+dsClPM8TPA4lVDoaSpf/zhXr7eRV hpy7Quq1cS15thMaGf3l+/BhZRy+p8g6c9WjG0iQBunqUAAaGvavdDCxCeZhaKFPYfJyH5CsW AN6Lom9Qe67RTbtuyInrmBMz/N/kjM8kI47zk7anLN2eu0EZW5yEPRlYkWAdRLXQM8At4G6mW KtlOsxZgjSQHIrHNMlxFCu/38v/hLNXkkT1NYGHqlBZiH9bGKFLXA0kzmG/H7HSiidFV3u7Z8 jJcwOAFmY8P2fOwZro5M6yXKWgibO2JecD1OZUZskATwlzYW0XSJ1xb2giIwlYtXtd7STr7yS MXcu2PCF+iHNQQoFbY7gskb7ABecJLQRCum8w0v1pwCGWbBXNdH+/8vPWTKt0kyU50Vug5bzK s3M3hgwfHzegdkr5auAXPrpCK0QLniG/soM4SDwNO7pSUVXtBYJ+6dx994XODA9mHyu4yuKfl SbRwiktn7CNvKePGHXHkba/ksuBKmEm99phdPhqSgyTQCP/iju7HR/wCrQVdM8d6GZN+1WNKd pLi69+KGYoyztXnb+QPHsDpIwQQxbNzRqPXPhzb+JUhetJOX/gwSJhfGKmciClLYu7gTm0V3Z 4/UBGWsZTxIRcL+z4WPoD/eTjYRUMT8dxyBlP6JNQYzhBBqnL+dcdV4/G8JvOGaSDATSUrMKQ eFet8Jg6EEhh61TCHnz/pQS+51PohdDR2tjIsVbioj3H9n10ieC1gSDzCnZjZB1zOdbnKlx8v 2RqdLETKhFhIWPvpLaMHCwNRSKKUBguKm+CrYxclOqSYPDbuPf8lEmEeWnrYXvD5uh9lY79HW VRZtJemxj1epdBzcrr4Y1mZ1icmMQIZ230qo3tGbDplSmoQalzyqSvo9bgXwrz7HAcehtrK6A V6lnF+rSNYK4ukaa7MUxv4aIMXmr40GnlaBd+9Gw9aW6uMfoLVHl4N5UXIYrPnRdGXUOmRCEZ eyQbxo96e6KABwSsP/fHkHRXI30ltipt3z3XpfRJiCGezZP63b0Y1HPaVxYHOC9h4ndXqvEJS QX7TgPgU+h3VS6q8TSAMW1nUxFY2UIAmJjLjQP1nt4XUabTC63I1AApwJnpjG1ZrsnCf7YfbJ j+18TaM6yEWPnyFyvcjfK/KAMTyAt1RW8kkTHCu4+aDaxP+nO9KfJKjyOzLI7mBOzE3mH1VC4 a6x1KTO2RTzxH2dmWjoWoJzbO2lz91QtNVfmztZDzyberxpAKMa+Qg+OVBnd82EHnhPME8zpZ Qn1UHW/ljI17D2iUUQBZHNNr0aJspoO1JukEJrrvlQfETvQUSKK0ycbgUYRKUqX+QGFtNtVMR k1hOO891Q4MTS5wNy+A1l43LwXK7+Oa2SorF0QZurlf+P+KUjPVBcSQxY6MvN0T28wnbhXxWH zoR7O1v659OuezwFVxxLNvf9pWG6KlX40SeZgLA3sl+nZxGCy+JgITf41hC2WjmvscfsetqvH 8k4TZsX9L0J6GNCldeInTr3Tp2QVOX0ng1MQsIIkTm4CYji2Ll2WxJceuQ+JQMCs01WuZacqq XnxSlguJOJGY1WrwnVI2fMrfrepOtr++ZDODXzg80DewnR3IfdyWAUIERCaTGKvTnJbP4mCqj YrAjD96JrWCF9f2/bkS1bLgBp8lwpSGCEqrXKiNvYiSHe9cIKIsLxjf8MfWygiPgRcTTvJaKb S50gH4SZ3DbhTaI6wygvjAlWbkVwErxz8L9DNRx8V/Vx3UFNAzbUu/BxTVEfSt4EfGZ1uAm6e 00cG+T8jIiEEsTrw6IoQRGn30vMyVLQ5aRkmOpwxGlY+XeB+UXKVNjTfqDfISSmV4x+/pzUiR dEbksuFz+2wl/XcR14Ou0dLC/pPufIPnqjkEMOoQnW6upXfIKIWZEo9OojlaHFH0N6zxZbRsW jbDoKu1DHusmYOBeswact8QZOYCeARUlxf6S0+/zLtK0vUePJwEteeObbz5bOSSjQ9S5kIG2Q w2QbqTyuH5cjld51AtBx6b5//Z2UmD85hh3iq6NABLGNuoMMJqzXKjKYtf8iqfoJhuaH5MB5F cDT/DplZkdFC2lSrVALgTbI7WEmgsL+nGmhN+74UtXVnT8lAkxN34 =E5=9C=A8 2025/6/26 09:14, Hillf Danton =E5=86=99=E9=81=93: > On Thu, 26 Jun 2025 06:59:14 +0930 Qu Wenruo wrote: >> =3DE5=3D9C=3DA8 2025/6/25 22:10, Hillf Danton =3DE5=3D86=3D99=3DE9=3D81= =3D93: >>> On Wed, 25 Jun 2025 20:19:06 +0930 Qu Wenruo wrote: >>>> =3D3DE5=3D3D9C=3D3DA8 2025/6/25 09:26, Hillf Danton =3D3DE5=3D3D86=3D= 3D99=3D3DE9=3D3D81=3D >> =3D3D93: >>>>> On Wed, 25 Jun 2025 06:00:09 +0930 Qu Wenruo wrote: >>>>>> =3D3D3DE5=3D3D3D9C=3D3D3DA8 2025/6/25 00:00, Edward Adam Davis =3D3= D3DE5=3D3D3D=3D >> 86=3D3D3D99=3D3D3DE9=3D3D >>>> =3D3D3D81=3D3D3D93: >>>>>>> Remove the lock uuid_mutex outside of sget_fc() to avoid the deadl= oc=3D >> k >>>>>>> reported by [1]. >>>>>>> =3D3D3D20 >>>>>>> [1] >>>>>>> -> #1 (&type->s_umount_key#41/1){+.+.}-{4:4}: >>>>>>> lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 >>>>>>> down_write_nested+0x9d/0x200 kernel/locking/rwsem.c:169= 3 >>>>>>> alloc_super+0x204/0x970 fs/super.c:345 >>>>> =3D3D20 >>>>> Given kzalloc [3], the syzbot report is false positive (a known lock= de=3D >> p >>>>> issue) as nobody else should acquire s->s_umount lock. >>>>> =3D3D20 >>>>> [3] https://web.git.kernel.org/pub/scm/linux/kernel/git/next/linux-n= ex=3D >> t.=3D3D >>>> git/tree/fs/super.c?id=3D3D3D7aacdf6feed1#n319 >>>> >>>> Not a false alert either. >>>> >>>> sget_fc() can return an existing super block, we can race between a= =3D3D2=3D >> 0 >>>> mount and an unmount on the same super block. >>>> >>>> In that case it's going to cause problem. >>>> >>>> This is already fixed in the v4 (and later v5) patchset: >>>> >>>> https://lore.kernel.org/linux-btrfs/cover.1750724841.git.wqu@suse.com= / >>>> >>> Can v5 survive the syzbot test? >> >> Yes, I enabled lockdep during v5 tests. >> > Fine, feel free to show us the Tested-by syzbot gave you. >=20 Here you go: https://lore.kernel.org/linux-btrfs/685d3d4c.050a0220.2303ee.01ca.GAE@goog= le.com/ That's based on a branch with extra patches though.