linux-toradex.git/kernel, branch v4.9.91

bpf: skip unnecessary capability check

2018-03-28T16:39:26+00:00

commit 0fa4fe85f4724fff89b09741c437cbee9cf8b008 upstream.

The current check statement in BPF syscall will do a capability check
for CAP_SYS_ADMIN before checking sysctl_unprivileged_bpf_disabled. This
code path will trigger unnecessary security hooks on capability checking
and cause false alarms on unprivileged process trying to get CAP_SYS_ADMIN
access. This can be resolved by simply switch the order of the statement
and CAP_SYS_ADMIN is not required anyway if unprivileged bpf syscall is
allowed.

Signed-off-by: Chenbo Feng 
Acked-by: Lorenzo Colitti 
Signed-off-by: Daniel Borkmann 
Signed-off-by: Greg Kroah-Hartman

tracing: probeevent: Fix to support minus offset from symbol

2018-03-28T16:39:23+00:00

commit c5d343b6b7badd1f5fe0873eff2e8d63a193e732 upstream.

In Documentation/trace/kprobetrace.txt, it says

 @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)

However, the parser doesn't parse minus offset correctly, since
commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
unsigned") drops minus ("-") offset support for kprobe probe
address usage.

This fixes the traceprobe_split_symbol_offset() to parse minus
offset again with checking the offset range, and add a minus
offset check in kprobe probe address usage.

Link: http://lkml.kernel.org/r/152129028983.31874.13419301530285775521.stgit@devbox

Cc: Ingo Molnar 
Cc: Tom Zanussi 
Cc: Arnaldo Carvalho de Melo 
Cc: Ravi Bangoria 
Cc: stable@vger.kernel.org
Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned")
Acked-by: Namhyung Kim 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

genirq: Use irqd_get_trigger_type to compare the trigger type for shared IRQs

2018-03-24T10:00:10+00:00

[ Upstream commit 382bd4de61827dbaaf5fb4fb7b1f4be4a86505e7 ]

When requesting a shared irq with IRQF_TRIGGER_NONE then the irqaction
flags get filled with the trigger type from the irq_data:

        if (!(new->flags & IRQF_TRIGGER_MASK))
                new->flags |= irqd_get_trigger_type(&desc->irq_data);

On the first setup_irq() the trigger type in irq_data is NONE when the
above code executes, then the irq is started up for the first time and
then the actual trigger type gets established, but that's too late to fix
up new->flags.

When then a second user of the irq requests the irq with IRQF_TRIGGER_NONE
its irqaction's triggertype gets set to the actual trigger type and the
following check fails:

        if (!((old->flags ^ new->flags) & IRQF_TRIGGER_MASK))

Resulting in the request_irq failing with -EBUSY even though both
users requested the irq with IRQF_SHARED | IRQF_TRIGGER_NONE

Fix this by comparing the new irqaction's trigger type to the trigger type
stored in the irq_data which correctly reflects the actual trigger type
being used for the irq.

Suggested-by: Thomas Gleixner 
Signed-off-by: Hans de Goede 
Acked-by: Marc Zyngier 
Link: http://lkml.kernel.org/r/20170415100831.17073-1-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

time: Change posix clocks ops interfaces to use timespec64

2018-03-24T10:00:09+00:00

[ Upstream commit d340266e19ddb70dbd608f9deedcfb35fdb9d419 ]

struct timespec is not y2038 safe on 32 bit machines.

The posix clocks apis use struct timespec directly and through struct
itimerspec.

Replace the posix clock interfaces to use struct timespec64 and struct
itimerspec64 instead.  Also fix up their implementations accordingly.

Note that the clock_getres() interface has also been changed to use
timespec64 even though this particular interface is not affected by the
y2038 problem. This helps verification for internal kernel code for y2038
readiness by getting rid of time_t/ timeval/ timespec.

Signed-off-by: Deepa Dinamani 
Cc: arnd@arndb.de
Cc: y2038@lists.linaro.org
Cc: netdev@vger.kernel.org
Cc: Richard Cochran 
Cc: john.stultz@linaro.org
Link: http://lkml.kernel.org/r/1490555058-4603-3-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

locking/locktorture: Fix num reader/writer corner cases

2018-03-22T08:17:58+00:00

[ Upstream commit 2ce77d16db4240dd2e422fc0a5c26d3e2ec03446 ]

Things can explode for locktorture if the user does combinations
of nwriters_stress=0 nreaders_stress=0. Fix this by not assuming
we always want to torture writer threads.

Reported-by: Jeremy Linton 
Signed-off-by: Davidlohr Bueso 
Signed-off-by: Paul E. McKenney 
Reviewed-by: Jeremy Linton 
Tested-by: Jeremy Linton 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sched: Stop resched_cpu() from sending IPIs to offline CPUs

2018-03-22T08:17:54+00:00

[ Upstream commit a0982dfa03efca6c239c52cabebcea4afb93ea6b ]

The rcutorture test suite occasionally provokes a splat due to invoking
resched_cpu() on an offline CPU:

WARNING: CPU: 2 PID: 8 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40
Modules linked in:
CPU: 2 PID: 8 Comm: rcu_preempt Not tainted 4.14.0-rc4+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
task: ffff902ede9daf00 task.stack: ffff96c50010c000
RIP: 0010:native_smp_send_reschedule+0x37/0x40
RSP: 0018:ffff96c50010fdb8 EFLAGS: 00010096
RAX: 000000000000002e RBX: ffff902edaab4680 RCX: 0000000000000003
RDX: 0000000080000003 RSI: 0000000000000000 RDI: 00000000ffffffff
RBP: ffff96c50010fdb8 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 00000000299f36ae R12: 0000000000000001
R13: ffffffff9de64240 R14: 0000000000000001 R15: ffffffff9de64240
FS:  0000000000000000(0000) GS:ffff902edfc80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f7d4c642 CR3: 000000001e0e2000 CR4: 00000000000006e0
Call Trace:
 resched_curr+0x8f/0x1c0
 resched_cpu+0x2c/0x40
 rcu_implicit_dynticks_qs+0x152/0x220
 force_qs_rnp+0x147/0x1d0
 ? sync_rcu_exp_select_cpus+0x450/0x450
 rcu_gp_kthread+0x5a9/0x950
 kthread+0x142/0x180
 ? force_qs_rnp+0x1d0/0x1d0
 ? kthread_create_on_node+0x40/0x40
 ret_from_fork+0x27/0x40
Code: 14 01 0f 92 c0 84 c0 74 14 48 8b 05 14 4f f4 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 38 89 ca 9d e8 e5 56 08 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 52 9e 37 02 85 c0 75 38 55 48
---[ end trace 26df9e5df4bba4ac ]---

This splat cannot be generated by expedited grace periods because they
always invoke resched_cpu() on the current CPU, which is good because
expedited grace periods require that resched_cpu() unconditionally
succeed.  However, other parts of RCU can tolerate resched_cpu() acting
as a no-op, at least as long as it doesn't happen too often.

This commit therefore makes resched_cpu() invoke resched_curr() only if
the CPU is either online or is the current CPU.

Signed-off-by: Paul E. McKenney 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

sched: Stop switched_to_rt() from sending IPIs to offline CPUs

2018-03-22T08:17:54+00:00

[ Upstream commit 2fe2582649aa2355f79acddb86bd4d6c5363eb63 ]

The rcutorture test suite occasionally provokes a splat due to invoking
rt_mutex_lock() which needs to boost the priority of a task currently
sitting on a runqueue that belongs to an offline CPU:

WARNING: CPU: 0 PID: 12 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40
Modules linked in:
CPU: 0 PID: 12 Comm: rcub/7 Not tainted 4.14.0-rc4+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
task: ffff9ed3de5f8cc0 task.stack: ffffbbf80012c000
RIP: 0010:native_smp_send_reschedule+0x37/0x40
RSP: 0018:ffffbbf80012fd10 EFLAGS: 00010082
RAX: 000000000000002f RBX: ffff9ed3dd9cb300 RCX: 0000000000000004
RDX: 0000000080000004 RSI: 0000000000000086 RDI: 00000000ffffffff
RBP: ffffbbf80012fd10 R08: 000000000009da7a R09: 0000000000007b9d
R10: 0000000000000001 R11: ffffffffbb57c2cd R12: 000000000000000d
R13: ffff9ed3de5f8cc0 R14: 0000000000000061 R15: ffff9ed3ded59200
FS:  0000000000000000(0000) GS:ffff9ed3dea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000080686f0 CR3: 000000001b9e0000 CR4: 00000000000006f0
Call Trace:
 resched_curr+0x61/0xd0
 switched_to_rt+0x8f/0xa0
 rt_mutex_setprio+0x25c/0x410
 task_blocks_on_rt_mutex+0x1b3/0x1f0
 rt_mutex_slowlock+0xa9/0x1e0
 rt_mutex_lock+0x29/0x30
 rcu_boost_kthread+0x127/0x3c0
 kthread+0x104/0x140
 ? rcu_report_unblock_qs_rnp+0x90/0x90
 ? kthread_create_on_node+0x40/0x40
 ret_from_fork+0x22/0x30
Code: f0 00 0f 92 c0 84 c0 74 14 48 8b 05 34 74 c5 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 a0 c6 fc b9 e8 d5 b5 06 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 a2 d1 13 02 85 c0 75 38 55 48

But the target task's priority has already been adjusted, so the only
purpose of switched_to_rt() invoking resched_curr() is to wake up the
CPU running some task that needs to be preempted by the boosted task.
But the CPU is offline, which presumably means that the task must be
migrated to some other CPU, and that this other CPU will undertake any
needed preemption at the time of migration.  Because the runqueue lock
is held when resched_curr() is invoked, we know that the boosted task
cannot go anywhere, so it is not necessary to invoke resched_curr()
in this particular case.

This commit therefore makes switched_to_rt() refrain from invoking
resched_curr() when the target CPU is offline.

Signed-off-by: Paul E. McKenney 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

printk: Correctly handle preemption in console_unlock()

2018-03-22T08:17:47+00:00

[ Upstream commit 257ab443118bffc7fdcef38f49cf59be68a3e362 ]

Some console drivers code calls console_conditional_schedule()
that looks at @console_may_schedule. The value must be cleared
when the drivers are called from console_unlock() with
interrupts disabled. But rescheduling is fine when the same
code is called, for example, from tty operations where the
console semaphore is taken via console_lock().

This is why @console_may_schedule is cleared before calling console
drivers. The original value is stored to decide if we could sleep
between lines.

Now, @console_may_schedule is not cleared when we call
console_trylock() and jump back to the "again" goto label.
This has become a problem, since the commit 6b97a20d3a7909daa066
("printk: set may_schedule for some of console_trylock() callers").
@console_may_schedule might get enabled now.

There is also the opposite problem. console_lock() can be called
only from preemptive context. It can always enable scheduling in
the console code. But console_trylock() is not able to detect it
when CONFIG_PREEMPT_COUNT is disabled. Therefore we should use the
original @console_may_schedule value after re-acquiring
the console semaphore in console_unlock().

This patch solves both problems by moving the "again" goto label.

Alternative solution was to clear and restore the value around
call_console_drivers(). Then console_conditional_schedule() could
be used also inside console_unlock(). But there was a potential race
with console_flush_on_panic() as reported by Sergey Senozhatsky.
That function should be called only where there is only one CPU
and with interrupts disabled. But better be on the safe side
because stopping CPUs might fail.

Fixes: 6b97a20d3a7909 ("printk: set may_schedule for some of console_trylock() callers")
Link: http://lkml.kernel.org/r/1490372045-22288-1-git-send-email-pmladek@suse.com
Suggested-by: Tetsuo Handa 
Cc: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Andrew Morton 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

rtmutex: Fix PI chain order integrity

2018-03-22T08:17:47+00:00

[ Upstream commit e0aad5b44ff5d28ac1d6ae70cdf84ca228e889dc ]

rt_mutex_waiter::prio is a copy of task_struct::prio which is updated
during the PI chain walk, such that the PI chain order isn't messed up
by (asynchronous) task state updates.

Currently rt_mutex_waiter_less() uses task state for deadline tasks;
this is broken, since the task state can, as said above, change
asynchronously, causing the RB tree order to change without actual
tree update -> FAIL.

Fix this by also copying the deadline into the rt_mutex_waiter state
and updating it along with its prio field.

Ideally we would also force PI chain updates whenever DL tasks update
their deadline parameter, but for first approximation this is less
broken than it was.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: juri.lelli@arm.com
Cc: bigeasy@linutronix.de
Cc: xlpang@redhat.com
Cc: rostedt@goodmis.org
Cc: mathieu.desnoyers@efficios.com
Cc: jdesfossez@efficios.com
Cc: bristot@redhat.com
Link: http://lkml.kernel.org/r/20170323150216.403992539@infradead.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

braille-console: Fix value returned by _braille_console_setup

2018-03-22T08:17:45+00:00

[ Upstream commit 2ed2b8621be2708c0f6d61fe9841e9ad8b9753f0 ]

commit bbeddf52adc1 ("printk: move braille console support into
separate braille.[ch] files") introduced _braille_console_setup()
to outline the braille initialization code.  There was however some
confusion over the value it was supposed to return. commit 2cfe6c4ac7ee
("printk: Fix return of braille_register_console()") tried to fix it
but failed to.

This fixes and documents the returned value according to the use
in printk.c: non-zero return means a parsing error, and thus this
console configuration should be ignored.

Signed-off-by: Samuel Thibault 
Cc: Aleksey Makarov 
Cc: Joe Perches 
Cc: Ming Lei 
Cc: Steven Rostedt 
Acked-by: Petr Mladek 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman