linux-stable.git/kernel, branch v4.19.37

kernel/sysctl.c: fix out-of-bounds access when setting file-max

2019-04-27T07:36:41+00:00

commit 9002b21465fa4d829edfc94a5a441005cffaa972 upstream.

Commit 32a5ad9c2285 ("sysctl: handle overflow for file-max") hooked up
min/max values for the file-max sysctl parameter via the .extra1 and
.extra2 fields in the corresponding struct ctl_table entry.

Unfortunately, the minimum value points at the global 'zero' variable,
which is an int.  This results in a KASAN splat when accessed as a long
by proc_doulongvec_minmax on 64-bit architectures:

  | BUG: KASAN: global-out-of-bounds in __do_proc_doulongvec_minmax+0x5d8/0x6a0
  | Read of size 8 at addr ffff2000133d1c20 by task systemd/1
  |
  | CPU: 0 PID: 1 Comm: systemd Not tainted 5.1.0-rc3-00012-g40b114779944 #2
  | Hardware name: linux,dummy-virt (DT)
  | Call trace:
  |  dump_backtrace+0x0/0x228
  |  show_stack+0x14/0x20
  |  dump_stack+0xe8/0x124
  |  print_address_description+0x60/0x258
  |  kasan_report+0x140/0x1a0
  |  __asan_report_load8_noabort+0x18/0x20
  |  __do_proc_doulongvec_minmax+0x5d8/0x6a0
  |  proc_doulongvec_minmax+0x4c/0x78
  |  proc_sys_call_handler.isra.19+0x144/0x1d8
  |  proc_sys_write+0x34/0x58
  |  __vfs_write+0x54/0xe8
  |  vfs_write+0x124/0x3c0
  |  ksys_write+0xbc/0x168
  |  __arm64_sys_write+0x68/0x98
  |  el0_svc_common+0x100/0x258
  |  el0_svc_handler+0x48/0xc0
  |  el0_svc+0x8/0xc
  |
  | The buggy address belongs to the variable:
  |  zero+0x0/0x40
  |
  | Memory state around the buggy address:
  |  ffff2000133d1b00: 00 00 00 00 00 00 00 00 fa fa fa fa 04 fa fa fa
  |  ffff2000133d1b80: fa fa fa fa 04 fa fa fa fa fa fa fa 04 fa fa fa
  | >ffff2000133d1c00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00
  |                                ^
  |  ffff2000133d1c80: fa fa fa fa 00 fa fa fa fa fa fa fa 00 00 00 00
  |  ffff2000133d1d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Fix the splat by introducing a unsigned long 'zero_ul' and using that
instead.

Link: http://lkml.kernel.org/r/20190403153409.17307-1-will.deacon@arm.com
Fixes: 32a5ad9c2285 ("sysctl: handle overflow for file-max")
Signed-off-by: Will Deacon 
Acked-by: Christian Brauner 
Cc: Kees Cook 
Cc: Alexey Dobriyan 
Cc: Matteo Croce 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

Revert "locking/lockdep: Add debug_locks check in __lock_downgrade()"

2019-04-27T07:36:41+00:00

This reverts commit 0e0f7b30721233ce610bde2395a8e58ff7771475 which was
commit 71492580571467fb7177aade19c18ce7486267f5 upstream.

Tetsuo rightly points out that the backport here is incorrect, as it
touches the __lock_set_class function instead of the intended
__lock_downgrade function.

Reported-by: Tetsuo Handa 
Cc: Waiman Long 
Cc: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: Ingo Molnar 
Cc: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup

2019-04-27T07:36:40+00:00

[ Upstream commit 2e8e19226398db8265a8e675fcc0118b9e80c9e8 ]

With extremely short cfs_period_us setting on a parent task group with a large
number of children the for loop in sched_cfs_period_timer() can run until the
watchdog fires. There is no guarantee that the call to hrtimer_forward_now()
will ever return 0.  The large number of children can make
do_sched_cfs_period_timer() take longer than the period.

 NMI watchdog: Watchdog detected hard LOCKUP on cpu 24
 RIP: 0010:tg_nop+0x0/0x10
  
  walk_tg_tree_from+0x29/0xb0
  unthrottle_cfs_rq+0xe0/0x1a0
  distribute_cfs_runtime+0xd3/0xf0
  sched_cfs_period_timer+0xcb/0x160
  ? sched_cfs_slack_timer+0xd0/0xd0
  __hrtimer_run_queues+0xfb/0x270
  hrtimer_interrupt+0x122/0x270
  smp_apic_timer_interrupt+0x6a/0x140
  apic_timer_interrupt+0xf/0x20
  

To prevent this we add protection to the loop that detects when the loop has run
too many times and scales the period and quota up, proportionally, so that the timer
can complete before then next period expires.  This preserves the relative runtime
quota while preventing the hard lockup.

A warning is issued reporting this state and the new values.

Signed-off-by: Phil Auld 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: 
Cc: Anton Blanchard 
Cc: Ben Segall 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: https://lkml.kernel.org/r/20190319130005.25492-1-pauld@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

timers/sched_clock: Prevent generic sched_clock wrap caused by tick_freeze()

2019-04-27T07:36:38+00:00

commit 3f2552f7e9c5abef2775c53f7af66532f8bf65bc upstream.

tick_freeze() introduced by suspend-to-idle in commit 124cf9117c5f ("PM /
sleep: Make it possible to quiesce timers during suspend-to-idle") uses
timekeeping_suspend() instead of syscore_suspend() during
suspend-to-idle. As a consequence generic sched_clock will keep going
because sched_clock_suspend() and sched_clock_resume() are not invoked
during suspend-to-idle which can result in a generic sched_clock wrap.

On a ARM system with suspend-to-idle enabled, sched_clock is registered
as "56 bits at 13MHz, resolution 76ns, wraps every 4398046511101ns", which
means the real wrapping duration is 8796093022202ns.

[  134.551779] suspend-to-idle suspend (timekeeping_suspend())
[ 1204.912239] suspend-to-idle resume (timekeeping_resume())
......
[ 1206.912239] suspend-to-idle suspend (timekeeping_suspend())
[ 5880.502807] suspend-to-idle resume (timekeeping_resume())
......
[ 6000.403724] suspend-to-idle suspend (timekeeping_suspend())
[ 8035.753167] suspend-to-idle resume  (timekeeping_resume())
......
[ 8795.786684] (2)[321:charger_thread]......
[ 8795.788387] (2)[321:charger_thread]......
[    0.057226] (0)[0:swapper/0]......
[    0.061447] (2)[0:swapper/2]......

sched_clock was not stopped during suspend-to-idle, and sched_clock_poll
hrtimer was not expired because timekeeping_suspend() was invoked during
suspend-to-idle. It makes sched_clock wrap at kernel time 8796s.

To prevent this, invoke sched_clock_suspend() and sched_clock_resume() in
tick_freeze() together with timekeeping_suspend() and timekeeping_resume().

Fixes: 124cf9117c5f (PM / sleep: Make it possible to quiesce timers during suspend-to-idle)
Signed-off-by: Chang-An Chen 
Signed-off-by: Thomas Gleixner 
Cc: Frederic Weisbecker 
Cc: Matthias Brugger 
Cc: John Stultz 
Cc: Kees Cook 
Cc: Corey Minyard 
Cc: 
Cc: 
Cc: Stanley Chu 
Cc: 
Cc: 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1553828349-8914-1-git-send-email-chang-an.chen@mediatek.com
Signed-off-by: Greg Kroah-Hartman

kprobes: Fix error check when reusing optimized probes

2019-04-27T07:36:37+00:00

commit 5f843ed415581cfad4ef8fefe31c138a8346ca8a upstream.

The following commit introduced a bug in one of our error paths:

  819319fc9346 ("kprobes: Return error if we fail to reuse kprobe instead of BUG_ON()")

it missed to handle the return value of kprobe_optready() as
error-value. In reality, the kprobe_optready() returns a bool
result, so "true" case must be passed instead of 0.

This causes some errors on kprobe boot-time selftests on ARM:

 [   ] Beginning kprobe tests...
 [   ] Probe ARM code
 [   ]     kprobe
 [   ]     kretprobe
 [   ] ARM instruction simulation
 [   ]     Check decoding tables
 [   ]     Run test cases
 [   ] FAIL: test_case_handler not run
 [   ] FAIL: Test andge	r10, r11, r14, asr r7
 [   ] FAIL: Scenario 11
 ...
 [   ] FAIL: Scenario 7
 [   ] Total instruction simulation tests=1631, pass=1433 fail=198
 [   ] kprobe tests failed

This can happen if an optimized probe is unregistered and next
kprobe is registered on same address until the previous probe
is not reclaimed.

If this happens, a hidden aggregated probe may be kept in memory,
and no new kprobe can probe same address. Also, in that case
register_kprobe() will return "1" instead of minus error value,
which can mislead caller logic.

Signed-off-by: Masami Hiramatsu 
Cc: Anil S Keshavamurthy 
Cc: David S . Miller 
Cc: Linus Torvalds 
Cc: Naveen N . Rao 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: stable@vger.kernel.org # v5.0+
Fixes: 819319fc9346 ("kprobes: Return error if we fail to reuse kprobe instead of BUG_ON()")
Link: http://lkml.kernel.org/r/155530808559.32517.539898325433642204.stgit@devnote2
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

kprobes: Mark ftrace mcount handler functions nokprobe

2019-04-27T07:36:37+00:00

commit fabe38ab6b2bd9418350284c63825f13b8a6abba upstream.

Mark ftrace mcount handler functions nokprobe since
probing on these functions with kretprobe pushes
return address incorrectly on kretprobe shadow stack.

Reported-by: Francis Deslauriers 
Tested-by: Andrea Righi 
Signed-off-by: Masami Hiramatsu 
Acked-by: Steven Rostedt 
Acked-by: Steven Rostedt (VMware) 
Cc: Linus Torvalds 
Cc: Mathieu Desnoyers 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/155094062044.6137.6419622920568680640.stgit@devbox
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

bpf: fix use after free in bpf_evict_inode

2019-04-20T07:16:05+00:00

[ Upstream commit 1da6c4d9140cb7c13e87667dc4e1488d6c8fc10f ]

syzkaller was able to generate the following UAF in bpf:

  BUG: KASAN: use-after-free in lookup_last fs/namei.c:2269 [inline]
  BUG: KASAN: use-after-free in path_lookupat.isra.43+0x9f8/0xc00 fs/namei.c:2318
  Read of size 1 at addr ffff8801c4865c47 by task syz-executor2/9423

  CPU: 0 PID: 9423 Comm: syz-executor2 Not tainted 4.20.0-rc1-next-20181109+
  #110
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
  Google 01/01/2011
  Call Trace:
    __dump_stack lib/dump_stack.c:77 [inline]
    dump_stack+0x244/0x39d lib/dump_stack.c:113
    print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
    kasan_report_error mm/kasan/report.c:354 [inline]
    kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
    __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430
    lookup_last fs/namei.c:2269 [inline]
    path_lookupat.isra.43+0x9f8/0xc00 fs/namei.c:2318
    filename_lookup+0x26a/0x520 fs/namei.c:2348
    user_path_at_empty+0x40/0x50 fs/namei.c:2608
    user_path include/linux/namei.h:62 [inline]
    do_mount+0x180/0x1ff0 fs/namespace.c:2980
    ksys_mount+0x12d/0x140 fs/namespace.c:3258
    __do_sys_mount fs/namespace.c:3272 [inline]
    __se_sys_mount fs/namespace.c:3269 [inline]
    __x64_sys_mount+0xbe/0x150 fs/namespace.c:3269
    do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
    entry_SYSCALL_64_after_hwframe+0x49/0xbe
  RIP: 0033:0x457569
  Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
  48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
  ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
  RSP: 002b:00007fde6ed96c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
  RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000457569
  RDX: 0000000020000040 RSI: 0000000020000000 RDI: 0000000000000000
  RBP: 000000000072bf00 R08: 0000000020000340 R09: 0000000000000000
  R10: 0000000000200000 R11: 0000000000000246 R12: 00007fde6ed976d4
  R13: 00000000004c2c24 R14: 00000000004d4990 R15: 00000000ffffffff

  Allocated by task 9424:
    save_stack+0x43/0xd0 mm/kasan/kasan.c:448
    set_track mm/kasan/kasan.c:460 [inline]
    kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
    __do_kmalloc mm/slab.c:3722 [inline]
    __kmalloc_track_caller+0x157/0x760 mm/slab.c:3737
    kstrdup+0x39/0x70 mm/util.c:49
    bpf_symlink+0x26/0x140 kernel/bpf/inode.c:356
    vfs_symlink+0x37a/0x5d0 fs/namei.c:4127
    do_symlinkat+0x242/0x2d0 fs/namei.c:4154
    __do_sys_symlink fs/namei.c:4173 [inline]
    __se_sys_symlink fs/namei.c:4171 [inline]
    __x64_sys_symlink+0x59/0x80 fs/namei.c:4171
    do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
    entry_SYSCALL_64_after_hwframe+0x49/0xbe

  Freed by task 9425:
    save_stack+0x43/0xd0 mm/kasan/kasan.c:448
    set_track mm/kasan/kasan.c:460 [inline]
    __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
    kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
    __cache_free mm/slab.c:3498 [inline]
    kfree+0xcf/0x230 mm/slab.c:3817
    bpf_evict_inode+0x11f/0x150 kernel/bpf/inode.c:565
    evict+0x4b9/0x980 fs/inode.c:558
    iput_final fs/inode.c:1550 [inline]
    iput+0x674/0xa90 fs/inode.c:1576
    do_unlinkat+0x733/0xa30 fs/namei.c:4069
    __do_sys_unlink fs/namei.c:4110 [inline]
    __se_sys_unlink fs/namei.c:4108 [inline]
    __x64_sys_unlink+0x42/0x50 fs/namei.c:4108
    do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
    entry_SYSCALL_64_after_hwframe+0x49/0xbe

In this scenario path lookup under RCU is racing with the final
unlink in case of symlinks. As Linus puts it in his analysis:

  [...] We actually RCU-delay the inode freeing itself, but
  when we do the final iput(), the "evict()" function is called
  synchronously. Now, the simple fix would seem to just RCU-delay
  the kfree() of the symlink data in bpf_evict_inode(). Maybe
  that's the right thing to do. [...]

Al suggested to piggy-back on the ->destroy_inode() callback in
order to implement RCU deferral there which can then kfree() the
inode->i_link eventually right before putting inode back into
inode cache. By reusing free_inode_nonrcu() from there we can
avoid the need for our own inode cache and just reuse generic
one as we currently do.

And in-fact on top of all this we should just get rid of the
bpf_evict_inode() entirely. This means truncate_inode_pages_final()
and clear_inode() will then simply be called by the fs core via
evict(). Dropping the reference should really only be done when
inode is unhashed and nothing reachable anymore, so it's better
also moved into the final ->destroy_inode() callback.

Fixes: 0f98621bef5d ("bpf, inode: add support for symlinks and fix mtime/ctime")
Reported-by: syzbot+fb731ca573367b7f6564@syzkaller.appspotmail.com
Reported-by: syzbot+a13e5ead792d6df37818@syzkaller.appspotmail.com
Reported-by: syzbot+7a8ba368b47fdefca61e@syzkaller.appspotmail.com
Suggested-by: Al Viro 
Analyzed-by: Linus Torvalds 
Signed-off-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Acked-by: Linus Torvalds 
Acked-by: Al Viro 
Link: https://lore.kernel.org/lkml/0000000000006946d2057bbd0eef@google.com/T/
Signed-off-by: Sasha Levin (Microsoft)

kernel: hung_task.c: disable on suspend

2019-04-20T07:16:02+00:00

[ Upstream commit a1c6ca3c6de763459a6e93b644ec6518c890ba1c ]

It is possible to observe hung_task complaints when system goes to
suspend-to-idle state:

 # echo freeze > /sys/power/state

 PM: Syncing filesystems ... done.
 Freezing user space processes ... (elapsed 0.001 seconds) done.
 OOM killer disabled.
 Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
 sd 0:0:0:0: [sda] Synchronizing SCSI cache
 INFO: task bash:1569 blocked for more than 120 seconds.
       Not tainted 4.19.0-rc3_+ #687
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 bash            D    0  1569    604 0x00000000
 Call Trace:
  ? __schedule+0x1fe/0x7e0
  schedule+0x28/0x80
  suspend_devices_and_enter+0x4ac/0x750
  pm_suspend+0x2c0/0x310

Register a PM notifier to disable the detector on suspend and re-enable
back on wakeup.

Signed-off-by: Vitaly Kuznetsov 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

sched/core: Fix buffer overflow in cgroup2 property cpu.max

2019-04-20T07:15:57+00:00

[ Upstream commit 4c47acd824aaaa8fc6dc519fb4e08d1522105b7a ]

Add limit into sscanf format string for on-stack buffer.

Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Tejun Heo 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: H. Peter Anvin 
Cc: Johannes Weiner 
Cc: Li Zefan 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Fixes: 0d5936344f30 ("sched: Implement interface for cgroup unified hierarchy")
Link: https://lkml.kernel.org/r/155189230232.2620.13120481613524200065.stgit@buzz
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

sched/cpufreq: Fix 32-bit math overflow

2019-04-20T07:15:57+00:00

[ Upstream commit a23314e9d88d89d49e69db08f60b7caa470f04e1 ]

Vincent Wang reported that get_next_freq() has a mult overflow bug on
32-bit platforms in the IOWAIT boost case, since in that case {util,max}
are in freq units instead of capacity units.

Solve this by moving the IOWAIT boost to capacity units. And since this
means @max is constant; simplify the code.

Reported-by: Vincent Wang 
Tested-by: Vincent Wang 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Rafael J. Wysocki 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Chunyan Zhang 
Cc: Dave Hansen 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Quentin Perret 
Cc: Rafael J. Wysocki 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Link: https://lkml.kernel.org/r/20190305083202.GU32494@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin