Commit Graph

1320 Commits

Author SHA1 Message Date
Peter Feiner
64e455079e mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared
For VMAs that don't want write notifications, PTEs created for read faults
have their write bit set.  If the read fault happens after VM_SOFTDIRTY is
cleared, then the PTE's softdirty bit will remain clear after subsequent
writes.

Here's a simple code snippet to demonstrate the bug:

  char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE,
                 MAP_ANONYMOUS | MAP_SHARED, -1, 0);
  system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */
  assert(*m == '\0');     /* new PTE allows write access */
  assert(!soft_dirty(x));
  *m = 'x';               /* should dirty the page */
  assert(soft_dirty(x));  /* fails */

With this patch, write notifications are enabled when VM_SOFTDIRTY is
cleared.  Furthermore, to avoid unnecessary faults, write notifications
are disabled when VM_SOFTDIRTY is set.

As a side effect of enabling and disabling write notifications with
care, this patch fixes a bug in mprotect where vm_page_prot bits set by
drivers were zapped on mprotect.  An analogous bug was fixed in mmap by
commit c9d0bf2414 ("mm: uncached vma support with writenotify").

Signed-off-by: Peter Feiner <pfeiner@google.com>
Reported-by: Peter Feiner <pfeiner@google.com>
Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-14 02:18:28 +02:00
Linus Torvalds
77c688ac87 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "The big thing in this pile is Eric's unmount-on-rmdir series; we
  finally have everything we need for that.  The final piece of prereqs
  is delayed mntput() - now filesystem shutdown always happens on
  shallow stack.

  Other than that, we have several new primitives for iov_iter (Matt
  Wilcox, culled from his XIP-related series) pushing the conversion to
  ->read_iter()/ ->write_iter() a bit more, a bunch of fs/dcache.c
  cleanups and fixes (including the external name refcounting, which
  gives consistent behaviour of d_move() wrt procfs symlinks for long
  and short names alike) and assorted cleanups and fixes all over the
  place.

  This is just the first pile; there's a lot of stuff from various
  people that ought to go in this window.  Starting with
  unionmount/overlayfs mess...  ;-/"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (60 commits)
  fs/file_table.c: Update alloc_file() comment
  vfs: Deduplicate code shared by xattr system calls operating on paths
  reiserfs: remove pointless forward declaration of struct nameidata
  don't need that forward declaration of struct nameidata in dcache.h anymore
  take dname_external() into fs/dcache.c
  let path_init() failures treated the same way as subsequent link_path_walk()
  fix misuses of f_count() in ppp and netlink
  ncpfs: use list_for_each_entry() for d_subdirs walk
  vfs: move getname() from callers to do_mount()
  gfs2_atomic_open(): skip lookups on hashed dentry
  [infiniband] remove pointless assignments
  gadgetfs: saner API for gadgetfs_create_file()
  f_fs: saner API for ffs_sb_create_file()
  jfs: don't hash direct inode
  [s390] remove pointless assignment of ->f_op in vmlogrdr ->open()
  ecryptfs: ->f_op is never NULL
  android: ->f_op is never NULL
  nouveau: __iomem misannotations
  missing annotation in fs/file.c
  fs: namespace: suppress 'may be used uninitialized' warnings
  ...
2014-10-13 11:28:42 +02:00
Linus Torvalds
b211e9d7c8 Merge branch 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
 "Nothing too interesting.  Just a handful of cleanup patches"

* 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  Revert "cgroup: remove redundant variable in cgroup_mount()"
  cgroup: remove redundant variable in cgroup_mount()
  cgroup: fix missing unlock in cgroup_release_agent()
  cgroup: remove CGRP_RELEASABLE flag
  perf/cgroup: Remove perf_put_cgroup()
  cgroup: remove redundant check in cgroup_ino()
  cpuset: simplify proc_cpuset_show()
  cgroup: simplify proc_cgroup_show()
  cgroup: use a per-cgroup work for release agent
  cgroup: remove bogus comments
  cgroup: remove redundant code in cgroup_rmdir()
  cgroup: remove some useless forward declarations
  cgroup: fix a typo in comment.
2014-10-10 07:24:40 -04:00
Konstantin Khlebnikov
09316c09dd mm/balloon_compaction: add vmstat counters and kpageflags bit
Always mark pages with PageBalloon even if balloon compaction is disabled
and expose this mark in /proc/kpageflags as KPF_BALLOON.

Also this patch adds three counters into /proc/vmstat: "balloon_inflate",
"balloon_deflate" and "balloon_migrate".  They accumulate balloon
activity.  Current size of balloon is (balloon_inflate - balloon_deflate)
pages.

All generic balloon code now gathered under option CONFIG_MEMORY_BALLOON.
It should be selected by ballooning driver which wants use this feature.
Currently virtio-balloon is the only user.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:01 -04:00
Peter Feiner
81d0fa623c mm: softdirty: unmapped addresses between VMAs are clean
If a /proc/pid/pagemap read spans a [VMA, an unmapped region, then a
VM_SOFTDIRTY VMA], the virtual pages in the unmapped region are reported
as softdirty.  Here's a program to demonstrate the bug:

int main() {
	const uint64_t PAGEMAP_SOFTDIRTY = 1ul << 55;
	uint64_t pme[3];
	int fd = open("/proc/self/pagemap", O_RDONLY);;
	char *m = mmap(NULL, 3 * getpagesize(), PROT_READ,
	               MAP_ANONYMOUS | MAP_SHARED, -1, 0);
	munmap(m + getpagesize(), getpagesize());
	pread(fd, pme, 24, (unsigned long) m / getpagesize() * 8);
	assert(pme[0] & PAGEMAP_SOFTDIRTY);    /* passes */
	assert(!(pme[1] & PAGEMAP_SOFTDIRTY)); /* fails */
	assert(pme[2] & PAGEMAP_SOFTDIRTY);    /* passes */
	return 0;
}

(Note that all pages in new VMAs are softdirty until cleared).

Tested:
	Used the program given above. I'm going to include this code in
	a selftest in the future.

[n-horiguchi@ah.jp.nec.com: prevent pagemap_pte_range() from overrunning]
Signed-off-by: Peter Feiner <pfeiner@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:58 -04:00
Oleg Nesterov
498f237178 mempolicy: fix show_numa_map() vs exec() + do_set_mempolicy() race
9e7814404b "hold task->mempolicy while numa_maps scans." fixed the
race with the exiting task but this is not enough.

The current code assumes that get_vma_policy(task) should either see
task->mempolicy == NULL or it should be equal to ->task_mempolicy saved
by hold_task_mempolicy(), so we can never race with __mpol_put(). But
this can only work if we can't race with do_set_mempolicy(), and thus
we can't race with another do_set_mempolicy() or do_exit() after that.

However, do_set_mempolicy()->down_write(mmap_sem) can not prevent this
race. This task can exec, change it's ->mm, and call do_set_mempolicy()
after that; in this case they take 2 different locks.

Change hold_task_mempolicy() to use get_task_policy(), it never returns
NULL, and change show_numa_map() to use __get_vma_policy() or fall back
to proc_priv->task_mempolicy.

Note: this is the minimal fix, we will cleanup this code later. I think
hold_task_mempolicy() and release_task_mempolicy() should die, we can
move this logic into show_numa_map(). Or we can move get_task_policy()
outside of ->mmap_sem and !CONFIG_NUMA code at least.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:56 -04:00
Baoquan He
bf3e269246 fs/proc/kcore.c: don't add modules range to kcore if it's equal to vmcore range
On some ARCHs modules range is eauql to vmalloc range. E.g on i686

	"#define MODULES_VADDR   VMALLOC_START"
	"#define MODULES_END     VMALLOC_END"

This will cause 2 duplicate program segments in /proc/kcore, and no flag
to indicate they are different.  This is confusing.  And usually people
who need check the elf header or read the content of kcore will check
memory ranges.  Two program segments which are the same are unnecessary.

So check if the modules range is equal to vmalloc range.  If so, just skip
adding the modules range.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:50 -04:00
Oleg Nesterov
58cb65487e proc/maps: make vm_is_stack() logic namespace-friendly
- Rename vm_is_stack() to task_of_stack() and change it to return
  "struct task_struct *" rather than the global (and thus wrong in
  general) pid_t.

- Add the new pid_of_stack() helper which calls task_of_stack() and
  uses the right namespace to report the correct pid_t.

  Unfortunately we need to define this helper twice, in task_mmu.c
  and in task_nommu.c. perhaps it makes sense to add fs/proc/util.c
  and move at least pid_of_stack/task_of_stack there to avoid the
  code duplication.

- Change show_map_vma() and show_numa_map() to use the new helper.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:50 -04:00
Oleg Nesterov
2c03376d2d proc/maps: replace proc_maps_private->pid with "struct inode *inode"
m_start() can use get_proc_task() instead, and "struct inode *"
provides more potentially useful info, see the next changes.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:50 -04:00
Oleg Nesterov
47fecca15c fs/proc/task_nommu.c: don't use priv->task->mm
I do not know if CONFIG_PREEMPT/SMP is possible without CONFIG_MMU
but the usage of task->mm in m_stop(). The task can exit/exec before
we take mmap_sem, in this case m_stop() can hit NULL or unlock the
wrong rw_semaphore.

Also, this code uses priv->task != NULL to decide whether we need
up_read/mmput. This is correct, but we will probably kill priv->task.
Change m_start/m_stop to rely on IS_ERR_OR_NULL() like task_mmu.c does.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
27692cd56e fs/proc/task_nommu.c: shift mm_access() from m_start() to proc_maps_open()
Copy-and-paste the changes from "fs/proc/task_mmu.c: shift mm_access()
from m_start() to proc_maps_open()" into task_nommu.c.

Change maps_open() to initialize priv->mm using proc_mem_open(), m_start()
can rely on atomic_inc_not_zero(mm_users) like task_mmu.c does.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
ce34fddb5b fs/proc/task_nommu.c: change maps_open() to use __seq_open_private()
Cleanup and preparation. maps_open() can use __seq_open_private()
like proc_maps_open() does.

[akpm@linux-foundation.org: deuglify]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
557c2d8a73 fs/proc/task_mmu.c: update m->version in the main loop in m_start()
Change the main loop in m_start() to update m->version. Mostly for
consistency, but this can help to avoid the same loop if the very
1st ->show() fails due to seq_overflow().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
b8c20a9b85 fs/proc/task_mmu.c: reintroduce m->version logic
Add the "last_addr" optimization back. Like before, every ->show()
method checks !seq_overflow() and sets m->version = vma->vm_start.

However, it also checks that m_next_vma(vma) != NULL, otherwise it
sets m->version = -1 for the lockless "EOF" fast-path in m_start().

m_start() can simply do find_vma() + m_next_vma() if last_addr is
not zero, the code looks clear and simple and this case is clearly
separated from "scan vmas" path.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
ad2a00e4b7 fs/proc/task_mmu.c: introduce m_next_vma() helper
Extract the tail_vma/vm_next calculation from m_next() into the new
trivial helper, m_next_vma().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
0c255321f8 fs/proc/task_mmu.c: simplify m_start() to make it readable
Now that m->version is gone we can cleanup m_start(). In particular,

  - Remove the "unsigned long" typecast, m->index can't be negative
    or exceed ->map_count. But lets use "unsigned int pos" to make
    it clear that "pos < map_count" is safe.

  - Remove the unnecessary "vma != NULL" check in the main loop. It
    can't be NULL unless we have a vm bug.

  - This also means that "pos < map_count" case can simply return the
    valid vma and avoid "goto" and subsequent checks.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
ebb6cdde1a fs/proc/task_mmu.c: kill the suboptimal and confusing m->version logic
m_start() carefully documents, checks, and sets "m->version = -1" if
we are going to return NULL. The only problem is that we will be never
called again if m_start() returns NULL, so this is simply pointless
and misleading.

Otoh, ->show() methods m->version = 0 if vma == tail_vma and this is
just wrong, we want -1 in this case. And in fact we also want -1 if
->vm_next == NULL and ->tail_vma == NULL.

And it is not used consistently, the "scan vmas" loop in m_start()
should update last_addr too.

Finally, imo the whole "last_addr" logic in m_start() looks horrible.
find_vma(last_addr) is called unconditionally even if we are not going
to use the result. But the main problem is that this code participates
in tail_vma-or-NULL mess, and this looks simply unfixable.

Remove this optimization. We will add it back after some cleanups.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
0d5f5f45f9 fs/proc/task_mmu.c: shift "priv->task = NULL" from m_start() to m_stop()
1. There is no reason to reset ->tail_vma in m_start(), if we return
   IS_ERR_OR_NULL() it won't be used.

2. m_start() also clears priv->task to ensure that m_stop() won't use
   the stale pointer if we fail before get_task_struct(). But this is
   ugly and confusing, move this initialization in m_stop().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:49 -04:00
Oleg Nesterov
23d54837e4 fs/proc/task_mmu.c: cleanup the "tail_vma" horror in m_next()
1. Kill the first "vma != NULL" check. Firstly this is not possible,
   m_next() won't be called if ->start() or the previous ->next()
   returns NULL.

   And if it was possible the 2nd "vma != tail_vma" check is buggy,
   we should not wrongly return ->tail_vma.

2. Make this function readable. The logic is very simple, we should
   return check "vma != tail" once and return "vm_next || tail_vma".

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:48 -04:00
Oleg Nesterov
59b4bf12d4 fs/proc/task_mmu.c: simplify the vma_stop() logic
m_start() drops ->mmap_sem and does mmput() if it retuns vsyscall
vma. This is because in this case m_stop()->vma_stop() obviously
can't use gate_vma->vm_mm.

Now that we have proc_maps_private->mm we can simplify this logic:

  - Change m_start() to return with ->mmap_sem held unless it returns
    IS_ERR_OR_NULL().

  - Change vma_stop() to use priv->mm and avoid the ugly vma checks,
    this makes "vm_area_struct *vma" unnecessary.

  - This also allows m_start() to use vm_stop().

  - Cleanup m_next() to follow the new locking rule.

    Note: m_stop() looks very ugly, and this temporary uglifies it
    even more. Fixed by the next change.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:48 -04:00
Oleg Nesterov
29a40ace84 fs/proc/task_mmu.c: shift mm_access() from m_start() to proc_maps_open()
A simple test-case from Kirill Shutemov

	cat /proc/self/maps >/dev/null
	chmod +x /proc/self/net/packet
	exec /proc/self/net/packet

makes lockdep unhappy, cat/exec take seq_file->lock + cred_guard_mutex in
the opposite order.

It's a false positive and probably we should not allow "chmod +x" on proc
files. Still I think that we should avoid mm_access() and cred_guard_mutex
in sys_read() paths, security checking should happen at open time. Besides,
this doesn't even look right if the task changes its ->mm between m_stop()
and m_start().

Add the new "mm_struct *mm" member into struct proc_maps_private and change
proc_maps_open() to initialize it using proc_mem_open(). Change m_start() to
use priv->mm if atomic_inc_not_zero(mm_users) succeeds or return NULL (eof)
otherwise.

The only complication is that proc_maps_open() users should additionally do
mmdrop() in fop->release(), add the new proc_map_release() helper for that.

Note: this is the user-visible change, if the task execs after open("maps")
the new ->mm won't be visible via this file. I hope this is fine, and this
matches /proc/pid/mem bahaviour.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:48 -04:00
Oleg Nesterov
5381e169e7 proc: introduce proc_mem_open()
Extract the mm_access() code from __mem_open() into the new helper,
proc_mem_open(), the next patch will add another caller.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:48 -04:00
Oleg Nesterov
4db7d0ee19 fs/proc/task_mmu.c: unify/simplify do_maps_open() and numa_maps_open()
do_maps_open() and numa_maps_open() are overcomplicated, they could use
__seq_open_private().  Plus they do the same, just sizeof(*priv)

Change them to use a new simple helper, proc_maps_open(ops, psize).  This
simplifies the code and allows us to do the next changes.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:48 -04:00
Oleg Nesterov
46c298cf69 fs/proc/task_mmu.c: don't use task->mm in m_start() and show_*map()
get_gate_vma(priv->task->mm) looks ugly and wrong, task->mm can be NULL or
it can changed by exec right after mm_access().

And in theory this race is not harmless, the task can exec and then later
exit and free the new mm_struct.  In this case get_task_mm(oldmm) can't
help, get_gate_vma(task->mm) can read the freed/unmapped memory.

I think that priv->task should simply die and hold_task_mempolicy() logic
can be simplified.  tail_vma logic asks for cleanups too.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:48 -04:00
Eric W. Biederman
bbd5192412 proc: Update proc_flush_task_mnt to use d_invalidate
Now that d_invalidate always succeeds and flushes mount points use
it in stead of a combination of shrink_dcache_parent and d_drop
in proc_flush_task_mnt.  This removes the danger of a mount point
under /proc/<pid>/... becoming unreachable after the d_drop.

Reviewed-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-09 02:38:58 -04:00
Eric W. Biederman
c143c2333c vfs: Remove d_drop calls from d_revalidate implementations
Now that d_invalidate always succeeds it is not longer necessary or
desirable to hard code d_drop calls into filesystem specific
d_revalidate implementations.

Remove the unnecessary d_drop calls and rely on d_invalidate
to drop the dentries.  Using d_invalidate ensures that paths
to mount points will not be dropped.

Reviewed-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-09 02:38:58 -04:00
Peter Feiner
87e6d49a00 mm: softdirty: addresses before VMAs in PTE holes aren't softdirty
In PTE holes that contain VM_SOFTDIRTY VMAs, unmapped addresses before
VM_SOFTDIRTY VMAs are reported as softdirty by /proc/pid/pagemap.  This
bug was introduced in commit 68b5a65248 ("mm: softdirty: respect
VM_SOFTDIRTY in PTE holes").  That commit made /proc/pid/pagemap look at
VM_SOFTDIRTY in PTE holes but neglected to observe the start of VMAs
returned by find_vma.

Tested:
  Wrote a selftest that creates a PMD-sized VMA then unmaps the first
  page and asserts that the page is not softdirty. I'm going to send the
  pagemap selftest in a later commit.

Signed-off-by: Peter Feiner <pfeiner@google.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Jamie Liu <jamieliu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-26 08:10:35 -07:00
Zefan Li
52de4779f2 cpuset: simplify proc_cpuset_show()
Use the ONE macro instead of REG, and we can simplify proc_cpuset_show().

Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-09-18 13:27:23 -04:00
Zefan Li
006f4ac497 cgroup: simplify proc_cgroup_show()
Use the ONE macro instead of REG, and we can simplify proc_cgroup_show().

Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-09-18 13:27:23 -04:00
Linus Torvalds
155134fef2 Revert "proc: Point /proc/{mounts,net} at /proc/thread-self/{mounts,net} instead of /proc/self/{mounts,net}"
This reverts commits 344470cac4 and e813244072.

It turns out that the exact path in the symlink matters, if for somewhat
unfortunate reasons: some apparmor configurations don't allow dhclient
access to the per-thread /proc files.  As reported by Jörg Otte:

  audit: type=1400 audit(1407684227.003:28): apparmor="DENIED"
    operation="open" profile="/sbin/dhclient"
    name="/proc/1540/task/1540/net/dev" pid=1540 comm="dhclient"
    requested_mask="r" denied_mask="r" fsuid=0 ouid=0

so we had better revert this for now.  We might be able to work around
this in practice by only using the per-thread symlinks if the thread
isn't the thread group leader, and if the namespaces differ between
threads (which basically never happens).

We'll see. In the meantime, the revert was made to be intentionally easy.

Reported-by: Jörg Otte <jrg.otte@gmail.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-10 21:24:59 -07:00
Linus Torvalds
77e40aae76 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman:
 "This is a bunch of small changes built against 3.16-rc6.  The most
  significant change for users is the first patch which makes setns
  drmatically faster by removing unneded rcu handling.

  The next chunk of changes are so that "mount -o remount,.." will not
  allow the user namespace root to drop flags on a mount set by the
  system wide root.  Aks this forces read-only mounts to stay read-only,
  no-dev mounts to stay no-dev, no-suid mounts to stay no-suid, no-exec
  mounts to stay no exec and it prevents unprivileged users from messing
  with a mounts atime settings.  I have included my test case as the
  last patch in this series so people performing backports can verify
  this change works correctly.

  The next change fixes a bug in NFS that was discovered while auditing
  nsproxy users for the first optimization.  Today you can oops the
  kernel by reading /proc/fs/nfsfs/{servers,volumes} if you are clever
  with pid namespaces.  I rebased and fixed the build of the
  !CONFIG_NFS_FS case yesterday when a build bot caught my typo.  Given
  that no one to my knowledge bases anything on my tree fixing the typo
  in place seems more responsible that requiring a typo-fix to be
  backported as well.

  The last change is a small semantic cleanup introducing
  /proc/thread-self and pointing /proc/mounts and /proc/net at it.  This
  prevents several kinds of problemantic corner cases.  It is a
  user-visible change so it has a minute chance of causing regressions
  so the change to /proc/mounts and /proc/net are individual one line
  commits that can be trivially reverted.  Unfortunately I lost and
  could not find the email of the original reporter so he is not
  credited.  From at least one perspective this change to /proc/net is a
  refgression fix to allow pthread /proc/net uses that were broken by
  the introduction of the network namespace"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  proc: Point /proc/mounts at /proc/thread-self/mounts instead of /proc/self/mounts
  proc: Point /proc/net at /proc/thread-self/net instead of /proc/self/net
  proc: Implement /proc/thread-self to point at the directory of the current thread
  proc: Have net show up under /proc/<tgid>/task/<tid>
  NFS: Fix /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes
  mnt: Add tests for unprivileged remount cases that have found to be faulty
  mnt: Change the default remount atime from relatime to the existing value
  mnt: Correct permission checks in do_remount
  mnt: Move the test for MNT_LOCK_READONLY from change_mount_flags into do_remount
  mnt: Only change user settable mount flags in remount
  namespaces: Use task_lock and not rcu to protect nsproxy
2014-08-09 17:10:41 -07:00
Joe Perches
e5eea0981a sysctl: remove typedef ctl_table
Remove the final user, and the typedef itself.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:24 -07:00
Vitaly Kuznetsov
0692dedcf6 fs/proc/vmcore.c:mmap_vmcore: skip non-ram pages reported by hypervisors
We have a special check in read_vmcore() handler to check if the page was
reported as ram or not by the hypervisor (pfn_is_ram()).  However, when
vmcore is read with mmap() no such check is performed.  That can lead to
unpredictable results, e.g.  when running Xen PVHVM guest memcpy() after
mmap() on /proc/vmcore will hang processing HVMMEM_mmio_dm pages creating
enormous load in both DomU and Dom0.

Fix the issue by mapping each non-ram page to the zero page.  Keep direct
path with remap_oldmem_pfn_range() to avoid looping through all pages on
bare metal.

The issue can also be solved by overriding remap_oldmem_pfn_range() in
xen-specific code, as remap_oldmem_pfn_range() was been designed for.
That, however, would involve non-obvious xen code path for all x86 builds
with CONFIG_XEN_PVHVM=y and would prevent all other hypervisor-specific
code on x86 arch from doing the same override.

[fengguang.wu@intel.com: remap_oldmem_pfn_checked() can be static]
[akpm@linux-foundation.org: clean up layout]
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:23 -07:00
Alexey Dobriyan
8f053ac11f proc: remove INF macro
If you're applying this patch, all /proc/$PID/* files were converted
to seq_file interface and this code became unused.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:23 -07:00
Alexey Dobriyan
d962c14483 proc: convert /proc/$PID/hardwall to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:23 -07:00
Alexey Dobriyan
19aadc98d6 proc: convert /proc/$PID/io to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:23 -07:00
Alexey Dobriyan
6ba51e3751 proc: convert /proc/$PID/oom_score to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:23 -07:00
Alexey Dobriyan
f6e826ca37 proc: convert /proc/$PID/schedstat to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:23 -07:00
Alexey Dobriyan
edfcd6064f proc: convert /proc/$PID/wchan to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:23 -07:00
Alexey Dobriyan
2ca66ff70a proc: convert /proc/$PID/cmdline to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:23 -07:00
Alexey Dobriyan
09d93bd627 proc: convert /proc/$PID/syscall to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Alexey Dobriyan
1c963eb135 proc: convert /proc/$PID/limits to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Alexey Dobriyan
f9ea536ef8 proc: convert /proc/$PID/auxv to seq_file interface
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Alexey Dobriyan
cedbccab8b proc: more "const char *" pointers
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Alexey Dobriyan
849d20a128 proc: remove proc_tty_ldisc variable
/proc/tty/ldisc appear to be unused as a directory and
it had been always that way.

But it is userspace visible thing.

Cowardly remove only in-kernel variable holding it.

[akpm@linux-foundation.org: add comment]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Alexey Dobriyan
4dcc03fc45 proc: make proc_subdir_lock static
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Alexey Dobriyan
335eb53158 proc: faster /proc/$PID lookup
Currently lookup for /proc/$PID first goes through spinlock and whole list
of misc /proc entries only to confirm that, yes, /proc/42 can not possibly
match random proc entry.

List is is several dozens entries long (52 entries on my setup).

None of this is necessary.

Try to convert dentry name to integer first.
If it works, it must be /proc/$PID.
If it doesn't, it must be random proc entry.

Based on patch from Al Viro.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Alexey Dobriyan
dbcdb50441 proc: add and remove /proc entry create checks
* remove proc_create(NULL, ...) check, let it oops

* warn about proc_create("", ...) and proc_create("very very long name", ...)
  proc code keeps length as u8, no 256+ name length possible

* warn about proc_create("123", ...)
  /proc/$PID and /proc/misc namespaces are separate things,
  but dumb module might create funky a-la $PID entry.

* remove post mortem strchr('/') check
  Triggering it implies either strchr() is buggy or memory corruption.
  It should be VFS check anyway.

In reality, none of these checks will ever trigger,
it is preparation for the next patch.

Based on patch from Al Viro.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Fabian Frederick
ccf94f1b4a proc: constify seq_operations
proc_uid_seq_operations, proc_gid_seq_operations and
proc_projid_seq_operations are only called in proc_id_map_open with
seq_open as const struct seq_operations so we can constify the 3
structures and update proc_id_map_open prototype.

   text    data     bss     dec     hex filename
   6817     404    1984    9205    23f5 kernel/user_namespace.o-before
   6913     308    1984    9205    23f5 kernel/user_namespace.o-after

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00
Fabian Frederick
108a8a11cb fs/proc/kcore.c: use PAGE_ALIGN instead of ALIGN(PAGE_SIZE)
Use mm.h definition.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:22 -07:00