linux-stable.git/kernel, branch v5.7.5

kernel/cpu_pm: Fix uninitted local in cpu_pm

2020-06-22T07:33:05+00:00

commit b5945214b76a1f22929481724ffd448000ede914 upstream.

cpu_pm_notify() is basically a wrapper of notifier_call_chain().
notifier_call_chain() doesn't initialize *nr_calls to 0 before it
starts incrementing it--presumably it's up to the callers to do this.

Unfortunately the callers of cpu_pm_notify() don't init *nr_calls.
This potentially means you could get too many or two few calls to
CPU_PM_ENTER_FAILED or CPU_CLUSTER_PM_ENTER_FAILED depending on the
luck of the stack.

Let's fix this.

Fixes: ab10023e0088 ("cpu_pm: Add cpu power management notifiers")
Cc: stable@vger.kernel.org
Cc: Rafael J. Wysocki 
Reviewed-by: Stephen Boyd 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20200504104917.v6.3.I2d44fc0053d019f239527a4e5829416714b7e299@changeid
Signed-off-by: Bjorn Andersson 
Signed-off-by: Greg Kroah-Hartman

clocksource: Remove obsolete ifdef

2020-06-22T07:33:01+00:00

commit c7f3d43b629b598a2bb9ec3524e844eae7492e7e upstream.

CONFIG_GENERIC_VDSO_CLOCK_MODE was a transitional config switch which got
removed after all architectures got converted to the new storage model.

But the removal forgot to remove the #ifdef which guards the
vdso_clock_mode sanity check, which effectively disables the sanity check.

Remove it now.

Fixes: f86fd32db706 ("lib/vdso: Cleanup clock mode storage leftovers")
Signed-off-by: Thomas Gleixner 
Tested-by: Miklos Szeredi 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200606221531.845475036@linutronix.de
Signed-off-by: Greg Kroah-Hartman

bpf: Fix map permissions check

2020-06-22T07:32:53+00:00

[ Upstream commit 1ea0f9120c8ce105ca181b070561df5cbd6bc049 ]

The map_lookup_and_delete_elem() function should check for both FMODE_CAN_WRITE
and FMODE_CAN_READ permissions because it returns a map element to user space.

Fixes: bd513cd08f10 ("bpf: add MAP_LOOKUP_AND_DELETE_ELEM syscall")
Signed-off-by: Anton Protopopov 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20200527185700.14658-5-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

sched: Defend cfs and rt bandwidth quota against overflow

2020-06-22T07:32:46+00:00

[ Upstream commit d505b8af58912ae1e1a211fabc9995b19bd40828 ]

When users write some huge number into cpu.cfs_quota_us or
cpu.rt_runtime_us, overflow might happen during to_ratio() shifts of
schedulable checks.

to_ratio() could be altered to avoid unnecessary internal overflow, but
min_cfs_quota_period is less than 1 << BW_SHIFT, so a cutoff would still
be needed. Set a cap MAX_BW for cfs_quota_us and rt_runtime_us to
prevent overflow.

Signed-off-by: Huaixin Chang 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Ben Segall 
Link: https://lkml.kernel.org/r/20200425105248.60093-1-changhuaixin@linux.alibaba.com
Signed-off-by: Sasha Levin

sched/core: Fix illegal RCU from offline CPUs

2020-06-22T07:32:36+00:00

[ Upstream commit bf2c59fce4074e55d622089b34be3a6bc95484fb ]

In the CPU-offline process, it calls mmdrop() after idle entry and the
subsequent call to cpuhp_report_idle_dead(). Once execution passes the
call to rcu_report_dead(), RCU is ignoring the CPU, which results in
lockdep complaining when mmdrop() uses RCU from either memcg or
debugobjects below.

Fix it by cleaning up the active_mm state from BP instead. Every arch
which has CONFIG_HOTPLUG_CPU should have already called idle_task_exit()
from AP. The only exception is parisc because it switches them to
&init_mm unconditionally (see smp_boot_one_cpu() and smp_cpu_init()),
but the patch will still work there because it calls mmgrab(&init_mm) in
smp_cpu_init() and then should call mmdrop(&init_mm) in finish_cpu().

  WARNING: suspicious RCU usage
  -----------------------------
  kernel/workqueue.c:710 RCU or wq_pool_mutex should be held!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  Call Trace:
   dump_stack+0xf4/0x164 (unreliable)
   lockdep_rcu_suspicious+0x140/0x164
   get_work_pool+0x110/0x150
   __queue_work+0x1bc/0xca0
   queue_work_on+0x114/0x120
   css_release+0x9c/0xc0
   percpu_ref_put_many+0x204/0x230
   free_pcp_prepare+0x264/0x570
   free_unref_page+0x38/0xf0
   __mmdrop+0x21c/0x2c0
   idle_task_exit+0x170/0x1b0
   pnv_smp_cpu_kill_self+0x38/0x2e0
   cpu_die+0x48/0x64
   arch_cpu_idle_dead+0x30/0x50
   do_idle+0x2f4/0x470
   cpu_startup_entry+0x38/0x40
   start_secondary+0x7a8/0xa80
   start_secondary_resume+0x10/0x14

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Qian Cai 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Michael Ellerman  (powerpc)
Link: https://lkml.kernel.org/r/20200401214033.8448-1-cai@lca.pw
Signed-off-by: Sasha Levin

exit: Move preemption fixup up, move blocking operations down

2020-06-22T07:32:36+00:00

[ Upstream commit 586b58cac8b4683eb58a1446fbc399de18974e40 ]

With CONFIG_DEBUG_ATOMIC_SLEEP=y and CONFIG_CGROUPS=y, kernel oopses in
non-preemptible context look untidy; after the main oops, the kernel prints
a "sleeping function called from invalid context" report because
exit_signals() -> cgroup_threadgroup_change_begin() -> percpu_down_read()
can sleep, and that happens before the preempt_count_set(PREEMPT_ENABLED)
fixup.

It looks like the same thing applies to profile_task_exit() and
kcov_task_exit().

Fix it by moving the preemption fixup up and the calls to
profile_task_exit() and kcov_task_exit() down.

Fixes: 1dc0fffc48af ("sched/core: Robustify preemption leak checks")
Signed-off-by: Jann Horn 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20200305220657.46800-1-jannh@google.com
Signed-off-by: Sasha Levin

audit: fix a net reference leak in audit_list_rules_send()

2020-06-22T07:32:31+00:00

[ Upstream commit 3054d06719079388a543de6adb812638675ad8f5 ]

If audit_list_rules_send() fails when trying to create a new thread
to send the rules it also fails to cleanup properly, leaking a
reference to a net structure.  This patch fixes the error patch and
renames audit_send_list() to audit_send_list_thread() to better
match its cousin, audit_send_reply_thread().

Reported-by: teroincn@gmail.com
Reviewed-by: Richard Guy Briggs 
Signed-off-by: Paul Moore 
Signed-off-by: Sasha Levin

audit: fix a net reference leak in audit_send_reply()

2020-06-22T07:32:30+00:00

[ Upstream commit a48b284b403a4a073d8beb72d2bb33e54df67fb6 ]

If audit_send_reply() fails when trying to create a new thread to
send the reply it also fails to cleanup properly, leaking a reference
to a net structure.  This patch fixes the error path and makes a
handful of other cleanups that came up while fixing the code.

Reported-by: teroincn@gmail.com
Reviewed-by: Richard Guy Briggs 
Signed-off-by: Paul Moore 
Signed-off-by: Sasha Levin

kgdb: Prevent infinite recursive entries to the debugger

2020-06-22T07:32:23+00:00

[ Upstream commit 3ca676e4ca60d1834bb77535dafe24169cadacef ]

If we detect that we recursively entered the debugger we should hack
our I/O ops to NULL so that the panic() in the next line won't
actually cause another recursion into the debugger.  The first line of
kgdb_panic() will check this and return.

Signed-off-by: Douglas Anderson 
Reviewed-by: Daniel Thompson 
Link: https://lore.kernel.org/r/20200507130644.v4.6.I89de39f68736c9de610e6f241e68d8dbc44bc266@changeid
Signed-off-by: Daniel Thompson 
Signed-off-by: Sasha Levin

kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb

2020-06-22T07:32:23+00:00

[ Upstream commit 202164fbfa2b2ffa3e66b504e0f126ba9a745006 ]

In commit 81eaadcae81b ("kgdboc: disable the console lock when in
kgdb") we avoided the WARN_CONSOLE_UNLOCKED() yell when we were in
kgdboc.  That still works fine, but it turns out that we get a similar
yell when using other I/O drivers.  One example is the "I/O driver"
for the kgdb test suite (kgdbts).  When I enabled that I again got the
same yells.

Even though "kgdbts" doesn't actually interact with the user over the
console, using it still causes kgdb to print to the consoles.  That
trips the same warning:
  con_is_visible+0x60/0x68
  con_scroll+0x110/0x1b8
  lf+0x4c/0xc8
  vt_console_print+0x1b8/0x348
  vkdb_printf+0x320/0x89c
  kdb_printf+0x68/0x90
  kdb_main_loop+0x190/0x860
  kdb_stub+0x2cc/0x3ec
  kgdb_cpu_enter+0x268/0x744
  kgdb_handle_exception+0x1a4/0x200
  kgdb_compiled_brk_fn+0x34/0x44
  brk_handler+0x7c/0xb8
  do_debug_exception+0x1b4/0x228

Let's increment/decrement the "ignore_console_lock_warning" variable
all the time when we enter the debugger.

This will allow us to later revert commit 81eaadcae81b ("kgdboc:
disable the console lock when in kgdb").

Signed-off-by: Douglas Anderson 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Daniel Thompson 
Link: https://lore.kernel.org/r/20200507130644.v4.1.Ied2b058357152ebcc8bf68edd6f20a11d98d7d4e@changeid
Signed-off-by: Daniel Thompson 
Signed-off-by: Sasha Levin