lkml.org 
[lkml]   [2006]   [Dec]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] libata: fix oops with sparsemem
Date
libata incorrectly passes NULL arguments to sg_set_buf, which
crashes on powerpc64 when looking for the corresponding mem_section.

This introduces a new ata_exec_nodma() wrapper that takes no buffer
arguments and does not call sg_set_buf either. In order to make it
easier to detect this sort of problem, it also adds a WARN_ON(!buf)
to sg_set_buf() so we get a log message even platforms without
sparsemem.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

Index: linux-2.6/drivers/ata/libata-core.c
===================================================================
--- linux-2.6.orig/drivers/ata/libata-core.c
+++ linux-2.6/drivers/ata/libata-core.c
@@ -1332,7 +1332,7 @@ unsigned ata_exec_internal_sg(struct ata
}

/**
- * ata_exec_internal_sg - execute libata internal command
+ * ata_exec_internal - execute libata internal command
* @dev: Device to which the command is sent
* @tf: Taskfile registers for the command and the result
* @cdb: CDB for packet command
@@ -1361,6 +1361,25 @@ unsigned ata_exec_internal(struct ata_de
}

/**
+ * ata_exec_nodma - execute libata internal command
+ * @dev: Device to which the command is sent
+ * @tf: Taskfile registers for the command and the result
+ *
+ * Wrapper around ata_exec_internal_sg() which takes no
+ * data buffer.
+ *
+ * LOCKING:
+ * None. Should be called with kernel context, might sleep.
+ *
+ * RETURNS:
+ * Zero on success, AC_ERR_* mask on failure
+ */
+static unsigned ata_exec_nodma(struct ata_device *dev, struct ata_taskfile *tf)
+{
+ return ata_exec_internal_sg(dev, tf, NULL, DMA_NONE, NULL, 0);
+}
+
+/**
* ata_do_simple_cmd - execute simple internal command
* @dev: Device to which the command is sent
* @cmd: Opcode to execute
@@ -1384,7 +1403,7 @@ unsigned int ata_do_simple_cmd(struct at
tf.flags |= ATA_TFLAG_DEVICE;
tf.protocol = ATA_PROT_NODATA;

- return ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
+ return ata_exec_nodma(dev, &tf);
}

/**
@@ -3475,7 +3494,7 @@ static unsigned int ata_dev_set_xfermode
tf.protocol = ATA_PROT_NODATA;
tf.nsect = dev->xfer_mode;

- err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
+ err_mask = ata_exec_nodma(dev, &tf);

DPRINTK("EXIT, err_mask=%x\n", err_mask);
return err_mask;
@@ -3513,7 +3532,7 @@ static unsigned int ata_dev_init_params(
tf.nsect = sectors;
tf.device |= (heads - 1) & 0x0f; /* max head = num. of heads - 1 */

- err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
+ err_mask = ata_exec_nodma(dev, &tf);

DPRINTK("EXIT, err_mask=%x\n", err_mask);
return err_mask;
Index: linux-2.6/include/linux/scatterlist.h
===================================================================
--- linux-2.6.orig/include/linux/scatterlist.h
+++ linux-2.6/include/linux/scatterlist.h
@@ -8,6 +8,8 @@
static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
unsigned int buflen)
{
+ WARN_ON(!buf); /* virt_to_page(NULL) crashes with sparsemem */
+
sg->page = virt_to_page(buf);
sg->offset = offset_in_page(buf);
sg->length = buflen;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2006-12-08 19:17    [W:0.029 / U:2.968 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site