On 09/21/2016 07:14 AM, Paul Jones wrote:
-----Original Message-----
From: linux-btrfs-ow...@vger.kernel.org [mailto:linux-btrfs-
ow...@vger.kernel.org] On Behalf Of Zygo Blaxell
Sent: Wednesday, 21 September 2016 2:56 PM
To: linux-btrfs@vger.kernel.org
Subject: btrfs rare silent data corruption with kernel data leak


There seem to be two btrfs bugs here: one loses data on writes, and the
other leaks data from the kernel to replace it on reads.  It all happens after
checksums are verified, so the corruption is entirely silent--no EIO errors,
kernel messages, or device event statistics.

Compressed extents are corrupted with kernel data leak.  Uncompressed
extents may not be corrupted, or may be corrupted by deterministically
replacing data bytes with zero, or may not be corrupted.  No preconditions
for corruption are known.  Less than one file per hundred thousand seems to
be affected.  Only specific parts of any file can be affected.
Kernels v4.0..v4.5.7 tested, all have the issue.

Zygo, could you please bounce me your original email? Somehow exchange ate it.

If you're seeing this databases that use fsync, it could be related to the fsync fix I put into the last RC. On my boxes it caused crashes, but memory corruptions aren't impossible.

Any chance you can do a controlled experiment to rule out compression?

To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to