From: Tejun Heo Date: Sun, 16 Aug 2009 12:21:21 +0000 (+0900) Subject: libata: fix off-by-one error in ata_tf_read_block() X-Git-Tag: v2.6.30.8~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=db4d3b9dedd857ae5f90301a654b7997132be7ae;p=thirdparty%2Fkernel%2Fstable.git libata: fix off-by-one error in ata_tf_read_block() 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 Reported-by: Atsushi Nemoto Signed-off-by: Jeff Garzik Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 7b2f499751aaa..bc20cf99076b5 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -709,7 +709,13 @@ u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev) 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;