https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=

[PATCH] Fix memory leak of dma_alloc_coherent() on x86_64

Description of problem:

The memory leak is generated by function dma_alloc_coherent()
on x86_64.

Especially, it is an extensive problem for the machine that 
installed hp Proliant Support Pack (=PSP). Because the memory 
leak path frequently passes by cciss_ioctl() of cmaidad and 
cmaeventd that work when PSP is installed.
The memory leak has been generated by the pace of "100KB/h -- 
15MB/h" in a certain hp PSP environment!!! The kernel entered
the state of a no response and rebooted.


This problem has already been fixed by Vanilla Kernel 2.6.10.
  - ChangeLog         : http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.10
  - VanillaKernelPatch:
http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commitdiff;h=792b87d770df447f3e4190d2b4732a3a36800adb
  > <ak>
  > 	[PATCH] x86_64: Fallback to swiotlb for dma_alloc_coherent
  > 	
  > 	From: Suresh B Siddha
  > 	
  > 	Coresponding change to IA64 code is in, so this can be merged too.
  > 	
  > 	- fallback to swiotlb for consistent DMA mappings
  > 	- fix a memory leak in dma_alloc_coherent


I hope that Red Hat takes my appended patch file to RHEL4.5 
kernel errata release.
  >diff -urN kernel-2.6.9-55.EL.org/arch/x86_64/kernel/pci-gart.c
kernel-2.6.9-55.EL/arch/x86_64/kernel/pci-gart.c
  >--- kernel-2.6.9-55.EL.org/arch/x86_64/kernel/pci-gart.c      2007-06-11
17:58:08.000000000 +0900
  >+++ kernel-2.6.9-55.EL/arch/x86_64/kernel/pci-gart.c      2007-06-11
17:58:38.000000000 +0900
  >@@ -238,6 +238,7 @@
  >                        if (high) {
  >                                if (!(gfp & GFP_DMA)) {
  >                                        gfp |= GFP_DMA;
  >+                                       free_pages((unsigned long)memory,
get_order(size));
  >                                        goto again;
  >                                }
  >                                goto free;


Steps to Reproduce & Actual results:

1. You install hp Proliant Support Pack.
2. hpasm service runs. (cmaidad and cmaeventd works.)
3. The hidden memory (*1) keeps increasing. 
   (example: memleak.png (Vertical: memleak amount [KB], Horizontal: time [min]))
   (*1): The hidden memory is a value of "MemTotal - MemFree - MemUsage(*2)" 
         in /proc/meminfo.
   (*2): The "MemUsage" is a value of "Active + Inactive + Slab + PageTables
         + VmallocUsed" in /proc/meminfo.

Expected results:

The memory leak is not generated by function dma_alloc_coherent().