linux-toradex.git/mm/nommu.c, branch v3.2.51

vm: add no-mmu vm_iomap_memory() stub

2013-09-10T00:57:10+00:00

commit 3c0b9de6d37a481673e81001c57ca0e410c72346 upstream.

I think we could just move the full vm_iomap_memory() function into
util.h or similar, but I didn't get any reply from anybody actually
using nommu even to this trivial patch, so I'm not going to touch it any
more than required.

Here's the fairly minimal stub to make the nommu case at least
potentially work.  It doesn't seem like anybody cares, though.

Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

mm: prevent mmap_cache race in find_vma()

2013-04-10T02:20:07+00:00

commit b6a9b7f6b1f21735a7456d534dc0e68e61359d2c upstream.

find_vma() can be called by multiple threads with read lock
held on mm->mmap_sem and any of them can update mm->mmap_cache.
Prevent compiler from re-fetching mm->mmap_cache, because other
readers could update it in the meantime:

               thread 1                             thread 2
                                        |
  find_vma()                            |  find_vma()
    struct vm_area_struct *vma = NULL;  |
    vma = mm->mmap_cache;               |
    if (!(vma && vma->vm_end > addr     |
        && vma->vm_start <= addr)) {    |
                                        |    mm->mmap_cache = vma;
    return vma;                         |
     ^^ compiler may optimize this      |
        local variable out and re-read  |
        mm->mmap_cache                  |

This issue can be reproduced with gcc-4.8.0-1 on s390x by running
mallocstress testcase from LTP, which triggers:

  kernel BUG at mm/rmap.c:1088!
    Call Trace:
     ([<000003d100c57000>] 0x3d100c57000)
      [<000000000023a1c0>] do_wp_page+0x2fc/0xa88
      [<000000000023baae>] handle_pte_fault+0x41a/0xac8
      [<000000000023d832>] handle_mm_fault+0x17a/0x268
      [<000000000060507a>] do_protection_exception+0x1e2/0x394
      [<0000000000603a04>] pgm_check_handler+0x138/0x13c
      [<000003fffcf1f07a>] 0x3fffcf1f07a
    Last Breaking-Event-Address:
      [<000000000024755e>] page_add_new_anon_rmap+0xc2/0x168

Thanks to Jakub Jelinek for his insight on gcc and helping to
track this down.

Signed-off-by: Jan Stancek 
Acked-by: David Rientjes 
Signed-off-by: Hugh Dickins 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings

NOMMU: Don't need to clear vm_mm when deleting a VMA

2012-03-12T19:31:25+00:00

commit b94cfaf6685d691dc3fab023cf32f65e9b7be09c upstream.

Don't clear vm_mm in a deleted VMA as it's unnecessary and might
conceivably break the filesystem or driver VMA close routine.

Reported-by: Al Viro 
Signed-off-by: David Howells 
Acked-by: Al Viro 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

NOMMU: Lock i_mmap_mutex for access to the VMA prio list

2012-03-01T00:31:11+00:00

commit 918e556ec214ed2f584e4cac56d7b29e4bb6bf27 upstream.

Lock i_mmap_mutex for access to the VMA prio list to prevent concurrent
access.  Currently, certain parts of the mmap handling are protected by
the region mutex, but not all.

Reported-by: Al Viro 
Signed-off-by: David Howells 
Acked-by: Al Viro 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

xen: map foreign pages for shared rings by updating the PTEs directly

2011-11-16T17:13:08+00:00

When mapping a foreign page with xenbus_map_ring_valloc() with the
GNTTABOP_map_grant_ref hypercall, set the GNTMAP_contains_pte flag and
pass a pointer to the PTE (in init_mm).

After the page is mapped, the usual fault mechanism can be used to
update additional MMs.  This allows the vmalloc_sync_all() to be
removed from alloc_vm_area().

Signed-off-by: David Vrabel 
Acked-by: Andrew Morton 
[v1: Squashed fix by Michal for no-mmu case]
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Michal Simek

mm: Map most files to use export.h instead of module.h

2011-10-31T13:20:12+00:00

The files changed within are only using the EXPORT_SYMBOL
macro variants.  They are not using core modular infrastructure
and hence don't need module.h but only the export.h header.

Signed-off-by: Paul Gortmaker

mmap: fix and tidy up overcommit page arithmetic

2011-07-26T03:57:09+00:00

- shmem pages are not immediately available, but they are not
  potentially available either, even if we swap them out, they will just
  relocate from memory into swap, total amount of immediate and
  potentially available memory is not going to be affected, so we
  shouldn't count them as potentially free in the first place.

- nr_free_pages() is not an expensive operation anymore, there is no
  need to split the decision making in two halves and repeat code.

Signed-off-by: Dmitry Fink 
Reviewed-by: Minchan Kim 
Acked-by: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc

2011-07-22T22:06:50+00:00

* 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc: (39 commits)
  ptrace: do_wait(traced_leader_killed_by_mt_exec) can block forever
  ptrace: fix ptrace_signal() && STOP_DEQUEUED interaction
  connector: add an event for monitoring process tracers
  ptrace: dont send SIGSTOP on auto-attach if PT_SEIZED
  ptrace: mv send-SIGSTOP from do_fork() to ptrace_init_task()
  ptrace_init_task: initialize child->jobctl explicitly
  has_stopped_jobs: s/task_is_stopped/SIGNAL_STOP_STOPPED/
  ptrace: make former thread ID available via PTRACE_GETEVENTMSG after PTRACE_EVENT_EXEC stop
  ptrace: wait_consider_task: s/same_thread_group/ptrace_reparented/
  ptrace: kill real_parent_is_ptracer() in in favor of ptrace_reparented()
  ptrace: ptrace_reparented() should check same_thread_group()
  redefine thread_group_leader() as exit_signal >= 0
  do not change dead_task->exit_signal
  kill task_detached()
  reparent_leader: check EXIT_DEAD instead of task_detached()
  make do_notify_parent() __must_check, update the callers
  __ptrace_detach: avoid task_detached(), check do_notify_parent()
  kill tracehook_notify_death()
  make do_notify_parent() return bool
  ptrace: s/tracehook_tracer_task()/ptrace_parent()/
  ...

mm/nommu.c: fix remap_pfn_range()

2011-07-09T04:14:44+00:00

remap_pfn_range() means map physical address pfn<vm_start = pfn << PAGE_SHIFT which
is wrong acroding the original meaning of this function.  And some driver
developer using remap_pfn_range() with correct parameter will get
unexpected result because vm_start is changed.  It should be implementd
like addr = pfn << PAGE_SHIFT but which is meanless on nommu arch, this
patch just make it simply return.

Parameter name and setting of vma->vm_flags also be fixed.

Signed-off-by: Bob Liu 
Cc: Geert Uytterhoeven 
Cc: David Howells 
Acked-by: Greg Ungerer 
Cc: Mike Frysinger 
Cc: Bob Liu 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ptrace: kill trivial tracehooks

2011-06-22T17:26:28+00:00

At this point, tracehooks aren't useful to mainline kernel and mostly
just add an extra layer of obfuscation.  Although they have comments,
without actual in-kernel users, it is difficult to tell what are their
assumptions and they're actually trying to achieve.  To mainline
kernel, they just aren't worth keeping around.

This patch kills the following trivial tracehooks.

* Ones testing whether task is ptraced.  Replace with ->ptrace test.

	tracehook_expect_breakpoints()
	tracehook_consider_ignored_signal()
	tracehook_consider_fatal_signal()

* ptrace_event() wrappers.  Call directly.

	tracehook_report_exec()
	tracehook_report_exit()
	tracehook_report_vfork_done()

* ptrace_release_task() wrapper.  Call directly.

	tracehook_finish_release_task()

* noop

	tracehook_prepare_release_task()
	tracehook_report_death()

This doesn't introduce any behavior change.

Signed-off-by: Tejun Heo 
Cc: Christoph Hellwig 
Cc: Martin Schwidefsky 
Signed-off-by: Oleg Nesterov