[patch 42/45] libata: fix off-by-one error in ata_tf_read_block()
From: Greg KH
Date: Wed Sep 16 2009 - 18:41:49 EST
2.6.31-stable review patch. If anyone has any objections, please let us know.
------------------
From: Tejun Heo <htejun@xxxxxxxxx>
commit ac8672ea922bde59acf50eaa1eaa1640a6395fd2 upstream.
ata_tf_read_block() has off-by-one error when converting CHS address
to LBA. The bug isn't very visible because ata_tf_read_block() is
used only when generating sense data for a failed RW command and CHS
addressing isn't used too often these days.
This problem was spotted by Atsushi Nemoto.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reported-by: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
Signed-off-by: Jeff Garzik <jgarzik@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/ata/libata-core.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -709,7 +709,13 @@ u64 ata_tf_read_block(struct ata_taskfil
head = tf->device & 0xf;
sect = tf->lbal;
- block = (cyl * dev->heads + head) * dev->sectors + sect;
+ if (!sect) {
+ ata_dev_printk(dev, KERN_WARNING, "device reported "
+ "invalid CHS sector 0\n");
+ sect = 1; /* oh well */
+ }
+
+ block = (cyl * dev->heads + head) * dev->sectors + sect - 1;
}
return block;
--
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