[PATCH] bug fix for megaraid memory leak and DOS against 2.6.5

[PATCH] bug fix for megaraid memory leak and DOS against 2.6.5

[Paul Wagland]

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Hi all,

Well, I was going through the code looking for bits and pieces to pull
across into the new LSI Logic beta megaraid driver /sys fs code and came
across this one.

LSI Logic have already fixed this issue for the 2.4 driver, and the new
beta driver does not use the /proc filesystem at all, so no problem
there.

The problem is that resources are not freed upon certain error
conditions in the in-kernel megaraid driver, to quote from Lester
Hightower (who originally found the issue):

---
The problem occurs only in the circumstance where one reads one of the
/proc/megaraid/hba<X>/diskdrives-ch<N> files where the card <X> does not
have channel <N> on it.  Most people would likely not notice this leak
in normal operation, but due to the way that we monitor our MegaRaid
cards in our company (we read these /proc entries every 180s) so we
found the leak rather quickly, and unpleasantly (when your kernel eats
all your RAM).
---

I leave it up to your own imagination as to how to DOS a machine using
this :-)

Anyway, here is the patch, compiled and tested OK for me.

Cheers,
Paul

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diff --recursive --unified linux-2.6.6-rc3/drivers/scsi/megaraid.c linux-2.6.6-rc3.new/drivers/scsi/megaraid.c
--- linux-2.6.6-rc3/drivers/scsi/megaraid.c	2004-04-04 05:36:12.000000000 +0200
+++ linux-2.6.6-rc3.new/drivers/scsi/megaraid.c	2004-05-04 01:19:15.000000000 +0200
@@ -2572,21 +2572,15 @@
 	}
 
 	if( (inquiry = mega_allocate_inquiry(&dma_handle, pdev)) == NULL ) {
-		free_local_pdev(pdev);
-		return len;
+		goto free_pdev;
 	}
 
 	if( mega_adapinq(adapter, dma_handle) != 0 ) {
-
 		len = sprintf(page, "Adapter inquiry failed.\n");
 
 		printk(KERN_WARNING "megaraid: inquiry failed.\n");
 
-		mega_free_inquiry(inquiry, dma_handle, pdev);
-
-		free_local_pdev(pdev);
-
-		return len;
+		goto free_inquiry;
 	}
 
 
@@ -2595,11 +2589,7 @@
 	if( scsi_inq == NULL ) {
 		len = sprintf(page, "memory not available for scsi inq.\n");
 
-		mega_free_inquiry(inquiry, dma_handle, pdev);
-
-		free_local_pdev(pdev);
-
-		return len;
+		goto free_inquiry;
 	}
 
 	if( adapter->flag & BOARD_40LD ) {
@@ -2612,7 +2602,9 @@
 
 	max_channels = adapter->product_info.nchannels;
 
-	if( channel >= max_channels ) return 0;
+	if( channel >= max_channels ) {
+		goto free_pci;
+	}
 
 	for( tgt = 0; tgt <= MAX_TARGET; tgt++ ) {
 
@@ -2677,10 +2669,11 @@
 		len += mega_print_inquiry(page+len, scsi_inq);
 	}
 
+free_pci:
 	pci_free_consistent(pdev, 256, scsi_inq, scsi_inq_dma_handle);
-
+free_inquiry:
 	mega_free_inquiry(inquiry, dma_handle, pdev);
-
+free_pdev:
 	free_local_pdev(pdev);
 
 	return len;

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