linux-stable.git/kernel, branch v4.4.21

uprobes: Fix the memcg accounting

2016-09-15T06:27:53+00:00

commit 6c4687cc17a788a6dd8de3e27dbeabb7cbd3e066 upstream.

__replace_page() wronlgy calls mem_cgroup_cancel_charge() in "success" path,
it should only do this if page_check_address() fails.

This means that every enable/disable leads to unbalanced mem_cgroup_uncharge()
from put_page(old_page), it is trivial to underflow the page_counter->count
and trigger OOM.

Reported-and-tested-by: Brenden Blanco 
Signed-off-by: Oleg Nesterov 
Reviewed-by: Johannes Weiner 
Acked-by: Michal Hocko 
Cc: Alexander Shishkin 
Cc: Alexei Starovoitov 
Cc: Arnaldo Carvalho de Melo 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Vladimir Davydov 
Fixes: 00501b531c47 ("mm: memcontrol: rewrite charge API")
Link: http://lkml.kernel.org/r/20160817153629.GB29724@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING

2016-09-15T06:27:52+00:00

commit 27727df240c7cc84f2ba6047c6f18d5addfd25ef upstream.

When I added some extra sanity checking in timekeeping_get_ns() under
CONFIG_DEBUG_TIMEKEEPING, I missed that the NMI safe __ktime_get_fast_ns()
method was using timekeeping_get_ns().

Thus the locking added to the debug checks broke the NMI-safety of
__ktime_get_fast_ns().

This patch open-codes the timekeeping_get_ns() logic for
__ktime_get_fast_ns(), so can avoid any deadlocks in NMI.

Fixes: 4ca22c2648f9 "timekeeping: Add warnings when overflows or underflows are observed"
Reported-by: Steven Rostedt 
Reported-by: Peter Zijlstra 
Signed-off-by: John Stultz 
Link: http://lkml.kernel.org/r/1471993702-29148-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

timekeeping: Cap array access in timekeeping_debug

2016-09-15T06:27:52+00:00

commit a4f8f6667f099036c88f231dcad4cf233652c824 upstream.

It was reported that hibernation could fail on the 2nd attempt, where the
system hangs at hibernate() -> syscore_resume() -> i8237A_resume() ->
claim_dma_lock(), because the lock has already been taken.

However there is actually no other process would like to grab this lock on
that problematic platform.

Further investigation showed that the problem is triggered by setting
/sys/power/pm_trace to 1 before the 1st hibernation.

Since once pm_trace is enabled, the rtc becomes unmeaningful after suspend,
and meanwhile some BIOSes would like to adjust the 'invalid' RTC (e.g, smaller
than 1970) to the release date of that motherboard during POST stage, thus
after resumed, it may seem that the system had a significant long sleep time
which is a completely meaningless value.

Then in timekeeping_resume -> tk_debug_account_sleep_time, if the bit31 of the
sleep time happened to be set to 1, fls() returns 32 and we add 1 to
sleep_time_bin[32], which causes an out of bounds array access and therefor
memory being overwritten.

As depicted by System.map:
0xffffffff81c9d080 b sleep_time_bin
0xffffffff81c9d100 B dma_spin_lock
the dma_spin_lock.val is set to 1, which caused this problem.

This patch adds a sanity check in tk_debug_account_sleep_time()
to ensure we don't index past the sleep_time_bin array.

[jstultz: Problem diagnosed and original patch by Chen Yu, I've solved the
 issue slightly differently, but borrowed his excelent explanation of the
 issue here.]

Fixes: 5c83545f24ab "power: Add option to log time spent in suspend"
Reported-by: Janek Kozicki 
Reported-by: Chen Yu 
Signed-off-by: John Stultz 
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra 
Cc: Xunlei Pang 
Cc: "Rafael J. Wysocki" 
Cc: Zhang Rui 
Link: http://lkml.kernel.org/r/1471993702-29148-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

cgroup: reduce read locked section of cgroup_threadgroup_rwsem during fork

2016-09-15T06:27:51+00:00

commit 568ac888215c7fb2fabe8ea739b00ec3c1f5d440 upstream.

cgroup_threadgroup_rwsem is acquired in read mode during process exit
and fork.  It is also grabbed in write mode during
__cgroups_proc_write().  I've recently run into a scenario with lots
of memory pressure and OOM and I am beginning to see

systemd

 __switch_to+0x1f8/0x350
 __schedule+0x30c/0x990
 schedule+0x48/0xc0
 percpu_down_write+0x114/0x170
 __cgroup_procs_write.isra.12+0xb8/0x3c0
 cgroup_file_write+0x74/0x1a0
 kernfs_fop_write+0x188/0x200
 __vfs_write+0x6c/0xe0
 vfs_write+0xc0/0x230
 SyS_write+0x6c/0x110
 system_call+0x38/0xb4

This thread is waiting on the reader of cgroup_threadgroup_rwsem to
exit.  The reader itself is under memory pressure and has gone into
reclaim after fork. There are times the reader also ends up waiting on
oom_lock as well.

 __switch_to+0x1f8/0x350
 __schedule+0x30c/0x990
 schedule+0x48/0xc0
 jbd2_log_wait_commit+0xd4/0x180
 ext4_evict_inode+0x88/0x5c0
 evict+0xf8/0x2a0
 dispose_list+0x50/0x80
 prune_icache_sb+0x6c/0x90
 super_cache_scan+0x190/0x210
 shrink_slab.part.15+0x22c/0x4c0
 shrink_zone+0x288/0x3c0
 do_try_to_free_pages+0x1dc/0x590
 try_to_free_pages+0xdc/0x260
 __alloc_pages_nodemask+0x72c/0xc90
 alloc_pages_current+0xb4/0x1a0
 page_table_alloc+0xc0/0x170
 __pte_alloc+0x58/0x1f0
 copy_page_range+0x4ec/0x950
 copy_process.isra.5+0x15a0/0x1870
 _do_fork+0xa8/0x4b0
 ppc_clone+0x8/0xc

In the meanwhile, all processes exiting/forking are blocked almost
stalling the system.

This patch moves the threadgroup_change_begin from before
cgroup_fork() to just before cgroup_canfork().  There is no nee to
worry about threadgroup changes till the task is actually added to the
threadgroup.  This avoids having to call reclaim with
cgroup_threadgroup_rwsem held.

tj: Subject and description edits.

Signed-off-by: Balbir Singh 
Acked-by: Zefan Li 
Cc: Oleg Nesterov 
Cc: Andrew Morton 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

kernel: Add noaudit variant of ns_capable()

2016-09-15T06:27:50+00:00

commit 98f368e9e2630a3ce3e80fb10fb2e02038cf9578 upstream.

When checking the current cred for a capability in a specific user
namespace, it isn't always desirable to have the LSMs audit the check.
This patch adds a noaudit variant of ns_capable() for when those
situations arise.

The common logic between ns_capable() and the new ns_capable_noaudit()
is moved into a single, shared function to keep duplicated code to a
minimum and ease maintainability.

Signed-off-by: Tyler Hicks 
Acked-by: Serge E. Hallyn 
Signed-off-by: James Morris 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

cred: Reject inodes with invalid ids in set_create_file_as()

2016-09-15T06:27:49+00:00

[ Upstream commit 5f65e5ca286126a60f62c8421b77c2018a482b8a ]

Using INVALID_[UG]ID for the LSM file creation context doesn't
make sense, so return an error if the inode passed to
set_create_file_as() has an invalid id.

Signed-off-by: Seth Forshee 
Acked-by: Serge Hallyn 
Signed-off-by: Eric W. Biederman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

clocksource: Allow unregistering the watchdog

2016-09-15T06:27:47+00:00

[ Upstream commit bbf66d897adf2bb0c310db96c97e8db6369f39e1 ]

Hyper-V vmbus module registers TSC page clocksource when loaded. This is
the clocksource with the highest rating and thus it becomes the watchdog
making unloading of the vmbus module impossible.
Separate clocksource_select_watchdog() from clocksource_enqueue_watchdog()
and use it on clocksource register/rating change/unregister.

After all, lobotomized monkeys may need some love too.

Signed-off-by: Vitaly Kuznetsov 
Cc: John Stultz 
Cc: Dexuan Cui 
Cc: K. Y. Srinivasan 
Link: http://lkml.kernel.org/r/1453483913-25672-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ntp: Fix ADJ_SETOFFSET being used w/ ADJ_NANO

2016-09-15T06:27:47+00:00

[ Upstream commit dd4e17ab704269bce71402285f5e8b9ac24b1eff ]

Recently, in commit 37cf4dc3370f I forgot to check if the timeval being passed
was actually a timespec (as is signaled with ADJ_NANO).

This resulted in that patch breaking ADJ_SETOFFSET users who set
ADJ_NANO, by rejecting valid timespecs that were compared with
valid timeval ranges.

This patch addresses this by checking for the ADJ_NANO flag and
using the timepsec check instead in that case.

Reported-by: Harald Hoyer 
Reported-by: Kay Sievers 
Fixes: 37cf4dc3370f "time: Verify time values in adjtimex ADJ_SETOFFSET to avoid overflow"
Signed-off-by: John Stultz 
Cc: Sasha Levin 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Cc: David Herrmann 
Link: http://lkml.kernel.org/r/1453417415-19110-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

time: Verify time values in adjtimex ADJ_SETOFFSET to avoid overflow

2016-09-15T06:27:47+00:00

[ Upstream commit 37cf4dc3370fbca0344e23bb96446eb2c3548ba7 ]

For adjtimex()'s ADJ_SETOFFSET, make sure the tv_usec value is
sane. We might multiply them later which can cause an overflow
and undefined behavior.

This patch introduces new helper functions to simplify the
checking code and adds comments to clarify

Orginally this patch was by Sasha Levin, but I've basically
rewritten it, so he should get credit for finding the issue
and I should get the blame for any mistakes made since.

Also, credit to Richard Cochran for the phrasing used in the
comment for what is considered valid here.

Cc: Sasha Levin 
Cc: Richard Cochran 
Cc: Thomas Gleixner 
Reported-by: Sasha Levin 
Signed-off-by: John Stultz 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sched/numa: Fix use-after-free bug in the task_numa_compare

2016-09-15T06:27:45+00:00

[ Upstream commit 1dff76b92f69051e579bdc131e01500da9fa2a91 ]

The following message can be observed on the Ubuntu v3.13.0-65 with KASan
backported:

  ==================================================================
  BUG: KASan: use after free in task_numa_find_cpu+0x64c/0x890 at addr ffff880dd393ecd8
  Read of size 8 by task qemu-system-x86/3998900
  =============================================================================
  BUG kmalloc-128 (Tainted: G    B        ): kasan: bad access detected
  -----------------------------------------------------------------------------

  INFO: Allocated in task_numa_fault+0xc1b/0xed0 age=41980 cpu=18 pid=3998890
	__slab_alloc+0x4f8/0x560
	__kmalloc+0x1eb/0x280
	task_numa_fault+0xc1b/0xed0
	do_numa_page+0x192/0x200
	handle_mm_fault+0x808/0x1160
	__do_page_fault+0x218/0x750
	do_page_fault+0x1a/0x70
	page_fault+0x28/0x30
	SyS_poll+0x66/0x1a0
	system_call_fastpath+0x1a/0x1f
  INFO: Freed in task_numa_free+0x1d2/0x200 age=62 cpu=18 pid=0
	__slab_free+0x2ab/0x3f0
	kfree+0x161/0x170
	task_numa_free+0x1d2/0x200
	finish_task_switch+0x1d2/0x210
	__schedule+0x5d4/0xc60
	schedule_preempt_disabled+0x40/0xc0
	cpu_startup_entry+0x2da/0x340
	start_secondary+0x28f/0x360
  Call Trace:
   [] dump_stack+0x45/0x56
   [] print_trailer+0xfd/0x170
   [] object_err+0x36/0x40
   [] kasan_report_error+0x1e9/0x3a0
   [] kasan_report+0x40/0x50
   [] ? task_numa_find_cpu+0x64c/0x890
   [] __asan_load8+0x69/0xa0
   [] ? find_next_bit+0xd8/0x120
   [] task_numa_find_cpu+0x64c/0x890
   [] task_numa_migrate+0x4ac/0x7b0
   [] numa_migrate_preferred+0xb3/0xc0
   [] task_numa_fault+0xb88/0xed0
   [] do_numa_page+0x192/0x200
   [] handle_mm_fault+0x808/0x1160
   [] ? sched_clock_cpu+0x10d/0x160
   [] ? native_load_tls+0x82/0xa0
   [] __do_page_fault+0x218/0x750
   [] ? hrtimer_try_to_cancel+0x76/0x160
   [] ? schedule_hrtimeout_range_clock.part.24+0xf7/0x1c0
   [] do_page_fault+0x1a/0x70
   [] page_fault+0x28/0x30
   [] ? do_sys_poll+0x1c4/0x6d0
   [] ? enqueue_task_fair+0x4b6/0xaa0
   [] ? sched_clock+0x9/0x10
   [] ? resched_task+0x7a/0xc0
   [] ? check_preempt_curr+0xb3/0x130
   [] ? poll_select_copy_remaining+0x170/0x170
   [] ? wake_up_state+0x10/0x20
   [] ? drop_futex_key_refs.isra.14+0x1f/0x90
   [] ? futex_requeue+0x3de/0xba0
   [] ? do_futex+0xbe/0x8f0
   [] ? read_tsc+0x9/0x20
   [] ? ktime_get_ts+0x12d/0x170
   [] ? timespec_add_safe+0x59/0xe0
   [] SyS_poll+0x66/0x1a0
   [] system_call_fastpath+0x1a/0x1f

As commit 1effd9f19324 ("sched/numa: Fix unsafe get_task_struct() in
task_numa_assign()") points out, the rcu_read_lock() cannot protect the
task_struct from being freed in the finish_task_switch(). And the bug
happens in the process of calculation of imp which requires the access of
p->numa_faults being freed in the following path:

do_exit()
        current->flags |= PF_EXITING;
    release_task()
        ~~delayed_put_task_struct()~~
    schedule()
    ...
    ...
rq->curr = next;
    context_switch()
        finish_task_switch()
            put_task_struct()
                __put_task_struct()
		    task_numa_free()

The fix here to get_task_struct() early before end of dst_rq->lock to
protect the calculation process and also put_task_struct() in the
corresponding point if finally the dst_rq->curr somehow cannot be
assigned.

Additional credit to Liang Chen who helped fix the error logic and add the
put_task_struct() to the place it missed.

Signed-off-by: Gavin Guo 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrea Arcangeli 
Cc: Andrew Morton 
Cc: Hugh Dickins 
Cc: Linus Torvalds 
Cc: Mel Gorman 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Cc: jay.vosburgh@canonical.com
Cc: liang.chen@canonical.com
Link: http://lkml.kernel.org/r/1453264618-17645-1-git-send-email-gavin.guo@canonical.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman