The patch titled
problems with cat /proc/kpageflags
has been added to the -mm tree. Its filename is
maps4-add-proc-kpageflags-interface-fix-2.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: problems with cat /proc/kpageflags
From: Matt Mackall <[EMAIL PROTECTED]>
On Thu, Dec 20, 2007 at 04:17:26PM -0800, David Miller wrote:
> From: Mariusz Kozlowski <[EMAIL PROTECTED]>
> Date: Thu, 20 Dec 2007 20:47:55 +0100
>
> > [ 145.128915] TSTATE: 0000004411009603 TPC: 00000000005119ac TNPC:
> > 00000000005119b0 Y: 00000000 Not tainted
> > [ 145.128940] TPC: <kpagecount_read+0x94/0xe0>
>
> My suspicion at this point is that with certain RAM layouts, simply
> iterating over PFN's is simply not working out.
That was my original suspicion, which is why I asked Mariusz to
effectively comment out the actual PFN lookup up-thread. I didn't send
him a patch to do that, so I guess my instructions on how to hack it
may have been misunderstood.
> pfn_to_page() seems to be doing no range checking, and with sparsemem
> vmemmap, which sparc64 always uses, this can be problematic.
>
> It just blindly goes "vmemmap + pfn" which is asking for trouble, in
> particular when the physical RAM layout really is sparse.
>
> Maybe it's enough to add a pfn_valid() check here? If pfn_valid()
> means there is a vmemmap translation setup for that page struct too,
> it would work.
Here's a test patch:
Cc: Mariusz Kozlowski <[EMAIL PROTECTED]>
Cc: David Miller <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
fs/proc/proc_misc.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff -puN fs/proc/proc_misc.c~maps4-add-proc-kpageflags-interface-fix-2
fs/proc/proc_misc.c
--- a/fs/proc/proc_misc.c~maps4-add-proc-kpageflags-interface-fix-2
+++ a/fs/proc/proc_misc.c
@@ -699,7 +699,10 @@ static ssize_t kpagecount_read(struct fi
return -EIO;
while (count > 0) {
- ppage = pfn_to_page(pfn++);
+ ppage = 0;
+ if (pfn_valid(pfn))
+ ppage = pfn_to_page(pfn);
+ pfn++;
if (!ppage)
pcount = 0;
else
@@ -762,7 +765,10 @@ static ssize_t kpageflags_read(struct fi
return -EIO;
while (count > 0) {
- ppage = pfn_to_page(pfn++);
+ ppage = 0;
+ if (pfn_valid(pfn))
+ ppage = pfn_to_page(pfn);
+ pfn++;
if (!ppage)
kflags = 0;
else
_
Patches currently in -mm which might be from [EMAIL PROTECTED] are
maps4-add-proportional-set-size-accounting-in-smaps.patch
maps4-rework-task_size-macros.patch
maps4-rework-task_size-macros-mips-fix.patch
maps4-move-is_swap_pte.patch
maps4-introduce-a-generic-page-walker.patch
maps4-use-pagewalker-in-clear_refs-and-smaps.patch
maps4-simplify-interdependence-of-maps-and-smaps.patch
maps4-move-clear_refs-code-to-task_mmuc.patch
maps4-regroup-task_mmu-by-interface.patch
maps4-add-proc-pid-pagemap-interface.patch
maps4-add-proc-kpagecount-interface.patch
maps4-add-proc-kpagecount-interface-fix.patch
maps4-add-proc-kpageflags-interface.patch
maps4-add-proc-kpageflags-interface-fix.patch
maps4-add-proc-kpageflags-interface-fix-2.patch
maps4-make-page-monitoring-proc-file-optional.patch
maps4-make-page-monitoring-proc-file-optional-fix.patch
remove-unused-code-from-mm-tiny-shmemc.patch
drivers-char-randomcwrite_pool-cond_resched-needed.patch
printk_ratelimit-functions-should-use-config_printk.patch
-
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