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From: Theodore Ts'o <tytso@mit.edu>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [REPORT] kernel BUG at fs/ext4/inode.c:2620 - page_buffers()
Date: Wed, 23 Feb 2022 23:04:34 -0500	[thread overview]
Message-ID: <YhcD0ugEyDMi4wXO@mit.edu> (raw)
In-Reply-To: <d75891d6-4c2e-57bc-f840-9d8d5449628a@nvidia.com>

On Wed, Feb 23, 2022 at 04:44:07PM -0800, John Hubbard wrote:
> 
> Actually...I can confirm that real customers really are doing *exactly* 
> that! Despite the kernel crashes--because the crashes don't always 
> happen unless you have a large (supercomputer-sized) installation. And 
> even then it is not always root-caused properly.

Interesting.  The syzbot reproducer triggers *reliably* on ext4 using
a 2 CPU qemu kernel running on a laptop, and it doesn't require root,
so it's reasonable that Lee is pushing for a fix --- even if for the
Android O or newer, Seccomp can probably prohibit trap
process_vm_writev(2), but it seems unfortunate if say, someone running
a Docker container could take down the entire host OS.

  	 	   	      	       	      - Ted



WARNING: multiple messages have this Message-ID (diff)
From: "Theodore Ts'o" <tytso@mit.edu>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Lee Jones <lee.jones@linaro.org>,
	linux-ext4@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	Dave Chinner <dchinner@redhat.com>,
	Goldwyn Rodrigues <rgoldwyn@suse.com>,
	"Darrick J . Wong" <darrick.wong@oracle.com>,
	Bob Peterson <rpeterso@redhat.com>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Andreas Gruenbacher <agruenba@redhat.com>,
	Ritesh Harjani <riteshh@linux.ibm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Johannes Thumshirn <jth@kernel.org>,
	linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	cluster-devel@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [REPORT] kernel BUG at fs/ext4/inode.c:2620 - page_buffers()
Date: Wed, 23 Feb 2022 23:04:34 -0500	[thread overview]
Message-ID: <YhcD0ugEyDMi4wXO@mit.edu> (raw)
In-Reply-To: <d75891d6-4c2e-57bc-f840-9d8d5449628a@nvidia.com>

On Wed, Feb 23, 2022 at 04:44:07PM -0800, John Hubbard wrote:
> 
> Actually...I can confirm that real customers really are doing *exactly* 
> that! Despite the kernel crashes--because the crashes don't always 
> happen unless you have a large (supercomputer-sized) installation. And 
> even then it is not always root-caused properly.

Interesting.  The syzbot reproducer triggers *reliably* on ext4 using
a 2 CPU qemu kernel running on a laptop, and it doesn't require root,
so it's reasonable that Lee is pushing for a fix --- even if for the
Android O or newer, Seccomp can probably prohibit trap
process_vm_writev(2), but it seems unfortunate if say, someone running
a Docker container could take down the entire host OS.

  	 	   	      	       	      - Ted

  reply	other threads:[~2022-02-24  4:04 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-16 16:31 [Cluster-devel] [REPORT] kernel BUG at fs/ext4/inode.c:2620 - page_buffers() Lee Jones
2022-02-16 16:31 ` Lee Jones
2022-02-18  1:06 ` [Cluster-devel] " John Hubbard
2022-02-18  1:06   ` John Hubbard
2022-02-18  4:08   ` [Cluster-devel] " Theodore Ts'o
2022-02-18  4:08     ` Theodore Ts'o
2022-02-18  6:33     ` [Cluster-devel] " John Hubbard
2022-02-18  6:33       ` John Hubbard
2022-02-23 23:31       ` [Cluster-devel] " Theodore Ts'o
2022-02-23 23:31         ` Theodore Ts'o
2022-02-24  0:44         ` [Cluster-devel] " John Hubbard
2022-02-24  0:44           ` John Hubbard
2022-02-24  4:04           ` Theodore Ts'o [this message]
2022-02-24  4:04             ` Theodore Ts'o
2022-02-18  7:51     ` [Cluster-devel] " Greg Kroah-Hartman
2022-02-18  7:51       ` Greg Kroah-Hartman
2022-02-23 23:35       ` [Cluster-devel] " Theodore Ts'o
2022-02-23 23:35         ` Theodore Ts'o
2022-02-24  1:48         ` [Cluster-devel] " Dave Chinner
2022-02-24  1:48           ` Dave Chinner
2022-02-24  3:50           ` [Cluster-devel] " Theodore Ts'o
2022-02-24  3:50             ` Theodore Ts'o
2022-02-24 10:29             ` [Cluster-devel] " Dave Chinner
2022-02-24 10:29               ` Dave Chinner
2022-02-18  2:54 ` [Cluster-devel] " Theodore Ts'o
2022-02-18  2:54   ` Theodore Ts'o
2022-02-18  4:24   ` [Cluster-devel] " Matthew Wilcox
2022-02-18  4:24     ` Matthew Wilcox
2022-02-18  6:03     ` [Cluster-devel] " Theodore Ts'o
2022-02-18  6:03       ` Theodore Ts'o
2022-02-25 19:24 ` [Cluster-devel] [PATCH -v2] ext4: don't BUG if kernel subsystems dirty pages without asking ext4 first Theodore Ts'o
2022-02-25 19:24   ` Theodore Ts'o
2022-02-25 20:51   ` [Cluster-devel] " Eric Biggers
2022-02-25 20:51     ` Eric Biggers
2022-02-25 21:08     ` [Cluster-devel] " Theodore Ts'o
2022-02-25 21:08       ` Theodore Ts'o
2022-02-25 21:23       ` [Cluster-devel] [PATCH -v3] " Theodore Ts'o
2022-02-25 21:23         ` Theodore Ts'o
2022-02-25 21:33         ` [Cluster-devel] " John Hubbard
2022-02-25 21:33           ` John Hubbard
2022-02-25 23:21           ` [Cluster-devel] " Theodore Ts'o
2022-02-25 23:21             ` Theodore Ts'o
2022-02-26  0:18             ` Hillf Danton
2022-02-26  0:41             ` [Cluster-devel] " John Hubbard
2022-02-26  0:41               ` John Hubbard
2022-02-26  1:40               ` [Cluster-devel] " Theodore Ts'o
2022-02-26  1:40                 ` Theodore Ts'o
2022-02-26  2:00                 ` [Cluster-devel] " Theodore Ts'o
2022-02-26  2:00                   ` Theodore Ts'o
2022-02-26  2:55                 ` [Cluster-devel] " John Hubbard
2022-02-26  2:55                   ` John Hubbard
2022-03-03  4:26         ` [Cluster-devel] [PATCH -v4] " Theodore Ts'o
2022-03-03  4:26           ` Theodore Ts'o
2022-03-03  8:21           ` [Cluster-devel] " Christoph Hellwig
2022-03-03  8:21             ` Christoph Hellwig
2022-03-03  9:21           ` [Cluster-devel] " Lee Jones
2022-03-03  9:21             ` Lee Jones
2022-03-03 14:38           ` [Cluster-devel] [PATCH -v5] ext4: don't BUG if someone " Theodore Ts'o
2022-03-03 14:38             ` Theodore Ts'o

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