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  1. 20 3月, 2012 1 次提交
  3. 06 12月, 2011 1 次提交
    • K
      x86/paravirt: PTE updates in k(un)map_atomic need to be synchronous, regardless of lazy_mmu mode · 2cd1c8d4
      由 Konrad Rzeszutek Wilk 提交于 
      Fix an outstanding issue that has been reported since 2.6.37.
Under a heavy loaded machine processing "fork()" calls could
crash with:

BUG: unable to handle kernel paging request at f573fc8c
IP: [<c01abc54>] swap_count_continued+0x104/0x180
*pdpt = 000000002a3b9027 *pde = 0000000001bed067 *pte = 0000000000000000 Oops: 0000 [#1] SMP
Modules linked in:
Pid: 1638, comm: apache2 Not tainted 3.0.4-linode37 #1
EIP: 0061:[<c01abc54>] EFLAGS: 00210246 CPU: 3
EIP is at swap_count_continued+0x104/0x180
.. snip..
Call Trace:
 [<c01ac222>] ? __swap_duplicate+0xc2/0x160
 [<c01040f7>] ? pte_mfn_to_pfn+0x87/0xe0
 [<c01ac2e4>] ? swap_duplicate+0x14/0x40
 [<c01a0a6b>] ? copy_pte_range+0x45b/0x500
 [<c01a0ca5>] ? copy_page_range+0x195/0x200
 [<c01328c6>] ? dup_mmap+0x1c6/0x2c0
 [<c0132cf8>] ? dup_mm+0xa8/0x130
 [<c013376a>] ? copy_process+0x98a/0xb30
 [<c013395f>] ? do_fork+0x4f/0x280
 [<c01573b3>] ? getnstimeofday+0x43/0x100
 [<c010f770>] ? sys_clone+0x30/0x40
 [<c06c048d>] ? ptregs_clone+0x15/0x48
 [<c06bfb71>] ? syscall_call+0x7/0xb

The problem is that in copy_page_range() we turn lazy mode on,
and then in swap_entry_free() we call swap_count_continued()
which ends up in:

         map = kmap_atomic(page, KM_USER0) + offset;

and then later we touch *map.

Since we are running in batched mode (lazy) we don't actually
set up the PTE mappings and the kmap_atomic is not done
synchronously and ends up trying to dereference a page that has
not been set.

Looking at kmap_atomic_prot_pfn(), it uses
'arch_flush_lazy_mmu_mode' and doing the same in
kmap_atomic_prot() and __kunmap_atomic() makes the problem go
away.

Interestingly, commit b8bcfe99 ("x86/paravirt: remove lazy
mode in interrupts") removed part of this to fix an interrupt
issue - but it went to far and did not consider this scenario.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      2cd1c8d4
  5. 28 10月, 2010 1 次提交
  7. 27 10月, 2010 1 次提交
    • P
      mm: stack based kmap_atomic() · 3e4d3af5
      由 Peter Zijlstra 提交于 
      Keep the current interface but ignore the KM_type and use a stack based
approach.

The advantage is that we get rid of crappy code like:

	#define __KM_PTE			\
		(in_nmi() ? KM_NMI_PTE : 	\
		 in_irq() ? KM_IRQ_PTE :	\
		 KM_PTE0)

and in general can stop worrying about what context we're in and what kmap
slots might be appropriate for that.

The downside is that FRV kmap_atomic() gets more expensive.

For now we use a CPP trick suggested by Andrew:

  #define kmap_atomic(page, args...) __kmap_atomic(page)

to avoid having to touch all kmap_atomic() users in a single patch.

[ not compiled on:
  - mn10300: the arch doesn't actually build with highmem to begin with ]

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c]
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3e4d3af5
  9. 10 8月, 2010 1 次提交
    • C
      kmap_atomic: make kunmap_atomic() harder to misuse · 597781f3
      由 Cesar Eduardo Barros 提交于 
      kunmap_atomic() is currently at level -4 on Rusty's "Hard To Misuse"
list[1] ("Follow common convention and you'll get it wrong"), except in
some architectures when CONFIG_DEBUG_HIGHMEM is set[2][3].

kunmap() takes a pointer to a struct page; kunmap_atomic(), however, takes
takes a pointer to within the page itself.  This seems to once in a while
trip people up (the convention they are following is the one from
kunmap()).

Make it much harder to misuse, by moving it to level 9 on Rusty's list[4]
("The compiler/linker won't let you get it wrong").  This is done by
refusing to build if the type of its first argument is a pointer to a
struct page.

The real kunmap_atomic() is renamed to kunmap_atomic_notypecheck()
(which is what you would call in case for some strange reason calling it
with a pointer to a struct page is not incorrect in your code).

The previous version of this patch was compile tested on x86-64.

[1] http://ozlabs.org/~rusty/index.cgi/tech/2008-04-01.html
[2] In these cases, it is at level 5, "Do it right or it will always
    break at runtime."
[3] At least mips and powerpc look very similar, and sparc also seems to
    share a common ancestor with both; there seems to be quite some
    degree of copy-and-paste coding here. The include/asm/highmem.h file
    for these three archs mention x86 CPUs at its top.
[4] http://ozlabs.org/~rusty/index.cgi/tech/2008-03-30.html
[5] As an aside, could someone tell me why mn10300 uses unsigned long as
    the first parameter of kunmap_atomic() instead of void *?
Signed-off-by: NCesar Eduardo Barros <cesarb@cesarb.net>
Cc: Russell King <linux@arm.linux.org.uk> (arch/arm)
Cc: Ralf Baechle <ralf@linux-mips.org> (arch/mips)
Cc: David Howells <dhowells@redhat.com> (arch/frv, arch/mn10300)
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> (arch/mn10300)
Cc: Kyle McMartin <kyle@mcmartin.ca> (arch/parisc)
Cc: Helge Deller <deller@gmx.de> (arch/parisc)
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> (arch/parisc)
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> (arch/powerpc)
Cc: Paul Mackerras <paulus@samba.org> (arch/powerpc)
Cc: "David S. Miller" <davem@davemloft.net> (arch/sparc)
Cc: Thomas Gleixner <tglx@linutronix.de> (arch/x86)
Cc: Ingo Molnar <mingo@redhat.com> (arch/x86)
Cc: "H. Peter Anvin" <hpa@zytor.com> (arch/x86)
Cc: Arnd Bergmann <arnd@arndb.de> (include/asm-generic)
Cc: Rusty Russell <rusty@rustcorp.com.au> ("Hard To Misuse" list)
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      597781f3
  11. 10 9月, 2009 1 次提交
  13. 29 7月, 2009 1 次提交
  15. 29 6月, 2009 1 次提交
  17. 04 4月, 2009 1 次提交
  19. 02 4月, 2009 1 次提交
  21. 01 4月, 2009 2 次提交
  23. 30 3月, 2009 1 次提交
  25. 13 3月, 2009 1 次提交
  27. 11 3月, 2009 2 次提交
  29. 05 3月, 2009 1 次提交
    • P
      x86: set_highmem_pages_init() cleanup, #2 · 6298e719
      由 Pekka Enberg 提交于 
      Impact: cleanup

The zones are set up at this stage so there's a highmem zone
available even for the UMA case.

The only difference there is that for machines that have
CONFIG_HIGHMEM enabled but don't have any highmem available,
->zone_start_pfn is zero whereas highstart_pfn is non-zero).

The field is left zeroed because of the !size test in
free_area_init_core() but shouldn't be a problem because
add_highpages_with_active_regions() handles empty ranges just
fine.
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: Mel Gorman <mel@csn.ul.ie>
LKML-Reference: <1236154567.29024.23.camel@penberg-laptop>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      6298e719
  31. 03 3月, 2009 2 次提交
  33. 18 10月, 2008 1 次提交
  35. 01 5月, 2008 1 次提交
  37. 29 3月, 2008 1 次提交
  39. 30 1月, 2008 1 次提交
  41. 11 10月, 2007 2 次提交
  43. 12 9月, 2007 1 次提交
    • A
      revert "highmem: catch illegal nesting" · 4150d3f5
      由 Andrew Morton 提交于 
      Revert

	commit 656dad31
	Author: Ingo Molnar <mingo@elte.hu>
	Date:   Sat Feb 10 01:46:36 2007 -0800

	[PATCH] highmem: catch illegal nesting

	Catch illegally nested kmap_atomic()s even if the page that is mapped by
	the 'inner' instance is from lowmem.

	This avoids spuriously zapped kmap-atomic ptes and turns hard to find
	crashes into clear asserts at the bug site.

Problem is, a get_zeroed_page(GFP_KERNEL) from interrupt context will trigger
this check if non-irq code on this CPU holds a KM_USER0 mapping.  But that
get_zeroed_page() will never be altering the kmap slot anyway due to the
GFP_KERNEL.

Cc: Christoph Lameter <clameter@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4150d3f5
  45. 03 5月, 2007 2 次提交
  47. 09 4月, 2007 1 次提交
  49. 12 2月, 2007 1 次提交
  51. 08 12月, 2006 2 次提交
  53. 01 10月, 2006 1 次提交
    • Z
      [PATCH] paravirt: kpte flush · 23002d88
      由 Zachary Amsden 提交于 
      Create a new PTE function which combines clearing a kernel PTE with the
subsequent flush.  This allows the two to be easily combined into a single
hypercall or paravirt-op.  More subtly, reverse the order of the flush for
kmap_atomic.  Instead of flushing on establishing a mapping, flush on clearing
a mapping.  This eliminates the possibility of leaving stale kmap entries
which may still have valid TLB mappings.  This is required for direct mode
hypervisors, which need to reprotect all mappings of a given page when
changing the page type from a normal page to a protected page (such as a page
table or descriptor table page).  But it also provides some nicer semantics
for real hardware, by providing extra debug-proofing against using stale
mappings, as well as ensuring that no stale mappings exist when changing the
cacheability attributes of a page, which could lead to cache conflicts when
two different types of mappings exist for the same page.
Signed-off-by: NZachary Amsden <zach@vmware.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      23002d88
  55. 26 9月, 2006 1 次提交
  57. 26 6月, 2005 1 次提交
  59. 24 6月, 2005 1 次提交
  61. 17 4月, 2005 1 次提交
    • L
      Linux-2.6.12-rc2 · 1da177e4
      由 Linus Torvalds 提交于 
      Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
      1da177e4