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[Qemu-block] [PATCH 0/3] block: Fix unaligned bdrv_aio_write_zeroes
From: |
Fam Zheng |
Subject: |
[Qemu-block] [PATCH 0/3] block: Fix unaligned bdrv_aio_write_zeroes |
Date: |
Fri, 24 Apr 2015 16:33:53 +0800 |
An unaligned zero write causes NULL deferencing in bdrv_co_do_pwritev. That
path is reachable from bdrv_co_write_zeroes and bdrv_aio_write_zeroes.
You can easily trigger through the former with qemu-io, as the test case added
by 61815d6e0aa. For bdrv_aio_write_zeroes, in common cases there's always a
format driver (which uses 512 alignment), so it would be much rarer to have
unaligned requests (only concerning top level here, when the request goes down
to bs->file, where for example the alignment is 4k, it would then be calling
bdrv_co_write_zeroes because it's in a coroutine).
fc3959e4669a1c fixed bdrv_co_write_zeroes but not bdrv_aio_write_zeroes. The
lattern is the actually used one by device model. Revert the previous fix, do
it in bdrv_co_do_pwritev, to cover both paths.
Fam
Fam Zheng (3):
scsi-disk: Limit zero write request to SCSI_WRITE_SAME_MAX
block: Fix NULL deference for unaligned write if qiov is NULL
Revert "block: Fix unaligned zero write"
block.c | 69 ++++++++++++++++++++---------------------------------
hw/scsi/scsi-disk.c | 7 +++++-
2 files changed, 32 insertions(+), 44 deletions(-)
--
1.9.3