[PATCH] 2.4.32 Don't panic on IDE DMA errors

[Chris Ross]

Kernel 2.4.32 and earlier can panic when trying to read a corrupted 
sector from an IDE disk.

The function ide_dma_timeout_retry can end a request early by calling 
idedisk_error, but then goes on to use the request anyway causing a 
kernel panic due to a null pointer exception. This patch fixes that.

Regards,
Chris R.


diff -urN -X dontdiff linux-2.4.32/drivers/ide/ide-io.c 
patched-linux-2.4.32/drivers/ide/ide-io.c
--- linux-2.4.32/drivers/ide/ide-io.c	2003-11-28 18:26:20.000000000 +0000
+++ patched-linux-2.4.32/drivers/ide/ide-io.c	2005-11-23 
12:33:37.000000000 +0000
@@ -899,11 +899,13 @@
 	rq = HWGROUP(drive)->rq;
 	HWGROUP(drive)->rq = NULL;

-	rq->errors = 0;
-	rq->sector = rq->bh->b_rsector;
-	rq->current_nr_sectors = rq->bh->b_size >> 9;
-	rq->hard_cur_sectors = rq->current_nr_sectors;
-	rq->buffer = rq->bh->b_data;
+	if (rq) {
+		rq->errors = 0;
+		rq->sector = rq->bh->b_rsector;
+		rq->current_nr_sectors = rq->bh->b_size >> 9;
+		rq->hard_cur_sectors = rq->current_nr_sectors;
+		rq->buffer = rq->bh->b_data;
+	}

 	return ret;
 }
-
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