Re: [x86_64] 2.6.14-git13 mplayer fails with "v4l2: ioctl queue buffer failed: Bad address" (2 Nov 2005, 11 Nov 2005)
Hi,
> This EFAULT rejection is due to change in get_user_pages() function
> in mm/memory.c file of 2.6.14-git2
>
>
> @@ -945,8 +947,8 @@ int get_user_pages(struct task_struct *t
> continue;
> }
>
> - if (!vma || (vma->vm_flags & VM_IO)
> - || !(flags & vma->vm_flags))
> + if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED))
> + || !(vm_flags & vma->vm_flags))
> return i ? : -EFAULT;
>
> if (is_vm_hugetlb_page(vma)) {
>
>
> I don't know how to use git tools to see, whose patch actually
> did this particular change.
To quote:
> MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
> deprecated. We never completely handled it correctly anyway, and is be
> reintroduced in future if required (Hugh has a proof of concept).
diff-tree b5810039a54e5babf428e9a1e89fc1940fabff11 (from f9c98d0287de42221c62448Author: Nick Piggin <nickpiggin@yahoo.com.au>
Date: Sat Oct 29 18:16:12 2005 -0700
[PATCH] core remove PageReserved
Remove PageReserved() calls from core code by tightening VM_RESERVED
handling in mm/ to cover PageReserved functionality.
PageReserved special casing is removed from get_page and put_page.
All setting and clearing of PageReserved is retained, and it is now flagged
in the page_alloc checks to help ensure we don't introduce any refcount
based freeing of Reserved pages.
MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
deprecated. We never completely handled it correctly anyway, and is be
reintroduced in future if required (Hugh has a proof of concept).
Once PageReserved() calls are removed from kernel/power/swsusp.c, and all
arch/ and driver code, the Set and Clear calls, and the PG_reserved bit can
be trivially removed.
Last real user of PageReserved is swsusp, which uses PageReserved to
determine whether a struct page points to valid memory or not. This still
needs to be addressed (a generic page_is_ram() should work).
A last caveat: the ZERO_PAGE is now refcounted and managed with rmap (and
thus mapcounted and count towards shared rss). These writes to the struct
page could cause excessive cacheline bouncing on big systems. There are a
number of ways this could be addressed if it is an issue.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Refcount bug fix for filemap_xip.c
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I think the relevant changes (snipped out) are:
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0c64484..da42093 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -157,7 +157,7 @@ extern unsigned int kobjsize(const void
#define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */
#define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */
-#define VM_RESERVED 0x00080000 /* Don't unmap it from swap_out */
+#define VM_RESERVED 0x00080000 /* Pages managed in a special way */
#define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
#define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
diff --git a/mm/memory.c b/mm/memory.c
index da642b5..e83f944 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -967,7 +992,7 @@ int get_user_pages(struct task_struct *t
continue;
}
- if (!vma || (vma->vm_flags & VM_IO)
+ if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED))
|| !(flags & vma->vm_flags))
return i ? : -EFAULT;
regards,
junichi
Reply to: