Pull timer fixes from Thomas Gleixner:
"A pile of fixes for long standing issues with the timer wheel and the
NOHZ code:
- Prevent timer base confusion accross the nohz switch, which can
cause unlocked access and data corruption
- Reinitialize the stale base clock on cpu hotplug to prevent subtle
side effects including rollovers on 32bit
- Prevent an interrupt storm when the timer softirq is already
pending caused by tick_nohz_stop_sched_tick()
- Move the timer start tracepoint to a place where it actually makes
sense
- Add documentation to timerqueue functions as they caused confusion
several times now"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timerqueue: Document return values of timerqueue_add/del()
timers: Invoke timer_start_debug() where it makes sense
nohz: Prevent a timer interrupt storm in tick_nohz_stop_sched_tick()
timers: Reinitialize per cpu bases on hotplug
timers: Use deferrable base independent of base::nohz_active
Pull smp fixlet from Thomas Gleixner:
"A trivial build warning fix for newer compilers"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Move inline keyword at the beginning of declaration
Pull scheduler fixes from Thomas Gleixner:
"Three patches addressing the fallout of the CPU_ISOLATION changes
especially with NO_HZ_FULL plus documentation of boot parameter
dependency"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/isolation: Document boot parameters dependency on CONFIG_CPU_ISOLATION=y
sched/isolation: Enable CONFIG_CPU_ISOLATION=y by default
sched/isolation: Make CONFIG_NO_HZ_FULL select CONFIG_CPU_ISOLATION
Pull irq fixes from Thomas Gleixner:
"A rather large update after the kaisered maintainer finally found time
to handle regression reports.
- The larger part addresses a regression caused by the x86 vector
management rework.
The reservation based model does not work reliably for MSI
interrupts, if they cannot be masked (yes, yet another hw
engineering trainwreck). The reason is that the reservation mode
assigns a dummy vector when the interrupt is allocated and switches
to a real vector when the interrupt is requested.
If the MSI entry cannot be masked then the initialization might
raise an interrupt before the interrupt is requested, which ends up
as spurious interrupt and causes device malfunction and worse. The
fix is to exclude MSI interrupts which do not support masking from
reservation mode and assign a real vector right away.
- Extend the extra lockdep class setup for nested interrupts with a
class for the recently added irq_desc::request_mutex so lockdep can
differeniate and does not emit false positive warnings.
- A ratelimit guard for the bad irq printout so in case a bad irq
comes back immediately the system does not drown in dmesg spam"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq/msi, x86/vector: Prevent reservation mode for non maskable MSI
genirq/irqdomain: Rename early argument of irq_domain_activate_irq()
x86/vector: Use IRQD_CAN_RESERVE flag
genirq: Introduce IRQD_CAN_RESERVE flag
genirq/msi: Handle reactivation only on success
gpio: brcmstb: Make really use of the new lockdep class
genirq: Guard handle_bad_irq log messages
kernel/irq: Extend lockdep class for request mutex
The timer start debug function is called before the proper timer base is
set. As a consequence the trace data contains the stale CPU and flags
values.
Call the debug function after setting the new base and flags.
Fixes: 500462a9de ("timers: Switch to a non-cascading wheel")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Cc: rt@linutronix.de
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Link: https://lkml.kernel.org/r/20171222145337.792907137@linutronix.de
The conditions in irq_exit() to invoke tick_nohz_irq_exit() which
subsequently invokes tick_nohz_stop_sched_tick() are:
if ((idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu))
If need_resched() is not set, but a timer softirq is pending then this is
an indication that the softirq code punted and delegated the execution to
softirqd. need_resched() is not true because the current interrupted task
takes precedence over softirqd.
Invoking tick_nohz_irq_exit() in this case can cause an endless loop of
timer interrupts because the timer wheel contains an expired timer, but
softirqs are not yet executed. So it returns an immediate expiry request,
which causes the timer to fire immediately again. Lather, rinse and
repeat....
Prevent that by adding a check for a pending timer soft interrupt to the
conditions in tick_nohz_stop_sched_tick() which avoid calling
get_next_timer_interrupt(). That keeps the tick sched timer on the tick and
prevents a repetitive programming of an already expired timer.
Reported-by: Sebastian Siewior <bigeasy@linutronix.d>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272156050.2431@nanos
The timer wheel bases are not (re)initialized on CPU hotplug. That leaves
them with a potentially stale clk and next_expiry valuem, which can cause
trouble then the CPU is plugged.
Add a prepare callback which forwards the clock, sets next_expiry to far in
the future and reset the control flags to a known state.
Set base->must_forward_clk so the first timer which is queued will try to
forward the clock to current jiffies.
Fixes: 500462a9de ("timers: Switch to a non-cascading wheel")
Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272152200.2431@nanos
During boot and before base::nohz_active is set in the timer bases, deferrable
timers are enqueued into the standard timer base. This works correctly as
long as base::nohz_active is false.
Once it base::nohz_active is set and a timer which was enqueued before that
is accessed the lock selector code choses the lock of the deferred
base. This causes unlocked access to the standard base and in case the
timer is removed it does not clear the pending flag in the standard base
bitmap which causes get_next_timer_interrupt() to return bogus values.
To prevent that, the deferrable timers must be enqueued in the deferrable
base, even when base::nohz_active is not set. Those deferrable timers also
need to be expired unconditional.
Fixes: 500462a9de ("timers: Switch to a non-cascading wheel")
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Cc: rt@linutronix.de
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Link: https://lkml.kernel.org/r/20171222145337.633328378@linutronix.de
The new reservation mode for interrupts assigns a dummy vector when the
interrupt is allocated and assigns a real vector when the interrupt is
requested. The reservation mode prevents vector pressure when devices with
a large amount of queues/interrupts are initialized, but only a minimal
subset of those queues/interrupts is actually used.
This mode has an issue with MSI interrupts which cannot be masked. If the
driver is not careful or the hardware emits an interrupt before the device
irq is requestd by the driver then the interrupt ends up on the dummy
vector as a spurious interrupt which can cause malfunction of the device or
in the worst case a lockup of the machine.
Change the logic for the reservation mode so that the early activation of
MSI interrupts checks whether:
- the device is a PCI/MSI device
- the reservation mode of the underlying irqdomain is activated
- PCI/MSI masking is globally enabled
- the PCI/MSI device uses either MSI-X, which supports masking, or
MSI with the maskbit supported.
If one of those conditions is false, then clear the reservation mode flag
in the irq data of the interrupt and invoke irq_domain_activate_irq() with
the reserve argument cleared. In the x86 vector code, clear the can_reserve
flag in the vector allocation data so a subsequent free_irq() won't create
the same situation again. The interrupt stays assigned to a real vector
until pci_disable_msi() is invoked and all allocations are undone.
Fixes: 4900be8360 ("x86/vector/msi: Switch to global reservation mode")
Reported-by: Alexandru Chirvasitu <achirvasub@gmail.com>
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexandru Chirvasitu <achirvasub@gmail.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Mikael Pettersson <mikpelinux@gmail.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: Mihai Costache <v-micos@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devel@linuxdriverproject.org
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@intel.com>,
Cc: linux-media@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712291406420.1899@nanos
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712291409460.1899@nanos
The 'early' argument of irq_domain_activate_irq() is actually used to
denote reservation mode. To avoid confusion, rename it before abuse
happens.
No functional change.
Fixes: 7249164346 ("genirq/irqdomain: Update irq_domain_ops.activate() signature")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexandru Chirvasitu <achirvasub@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Mikael Pettersson <mikpelinux@gmail.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: Mihai Costache <v-micos@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devel@linuxdriverproject.org
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@intel.com>,
Cc: linux-media@vger.kernel.org
Add a new flag to mark interrupts which can use reservation mode. This is
going to be used in subsequent patches to disable reservation mode for a
certain class of MSI devices.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexandru Chirvasitu <achirvasub@gmail.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Mikael Pettersson <mikpelinux@gmail.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: Mihai Costache <v-micos@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devel@linuxdriverproject.org
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@intel.com>,
Cc: linux-media@vger.kernel.org
When analyzing the fallout of the x86 vector allocation rework it turned
out that the error handling in msi_domain_alloc_irqs() is broken.
If MSI_FLAG_MUST_REACTIVATE is set for a MSI domain then it clears the
activation flag for a successfully initialized msi descriptor. If a
subsequent initialization fails then the error handling code path does not
deactivate the interrupt because the activation flag got cleared.
Move the clearing of the activation flag outside of the initialization loop
so that an eventual failure can be cleaned up correctly.
Fixes: 22d0b12f35 ("genirq/irqdomain: Add force reactivation flag to irq domains")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexandru Chirvasitu <achirvasub@gmail.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Mikael Pettersson <mikpelinux@gmail.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: Mihai Costache <v-micos@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devel@linuxdriverproject.org
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@intel.com>,
Cc: linux-media@vger.kernel.org
This fixes a schedutil cpufreq governor regression from the 4.14
cycle that may cause a CPU idleness check to return incorrect results
in some cases which leads to suboptimal decisions (Joel Fernandes).
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Merge tag 'pm-4.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fix from Rafael Wysocki:
"This fixes a schedutil cpufreq governor regression from the 4.14 cycle
that may cause a CPU idleness check to return incorrect results in
some cases which leads to suboptimal decisions (Joel Fernandes)"
* tag 'pm-4.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: schedutil: Use idle_calls counter of the remote CPU
An interrupt storm on a bad interrupt will cause the kernel
log to be clogged.
[ 60.089234] ->handle_irq(): ffffffffbe2f803f,
[ 60.090455] 0xffffffffbf2af380
[ 60.090510] handle_bad_irq+0x0/0x2e5
[ 60.090522] ->irq_data.chip(): ffffffffbf2af380,
[ 60.090553] IRQ_NOPROBE set
[ 60.090584] ->handle_irq(): ffffffffbe2f803f,
[ 60.090590] handle_bad_irq+0x0/0x2e5
[ 60.090596] ->irq_data.chip(): ffffffffbf2af380,
[ 60.090602] 0xffffffffbf2af380
[ 60.090608] ->action(): (null)
[ 60.090779] handle_bad_irq+0x0/0x2e5
This was seen when running an upstream kernel on Acer Chromebook R11. The
system was unstable as result.
Guard the log message with __printk_ratelimit to reduce the impact. This
won't prevent the interrupt storm from happening, but at least the system
remains stable.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Torokhov <dtor@chromium.org>
Cc: Joe Perches <joe@perches.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197953
Link: https://lkml.kernel.org/r/1512234784-21038-1-git-send-email-linux@roeck-us.net
Since the recent remote cpufreq callback work, its possible that a cpufreq
update is triggered from a remote CPU. For single policies however, the current
code uses the local CPU when trying to determine if the remote sg_cpu entered
idle or is busy. This is incorrect. To remedy this, compare with the nohz tick
idle_calls counter of the remote CPU.
Fixes: 674e75411f (sched: cpufreq: Allow remote cpufreq callbacks)
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Joel Fernandes <joelaf@google.com>
Cc: 4.14+ <stable@vger.kernel.org> # 4.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
were getting corrupted. In the process I found three bugs. One was the
culprit, but the other two scared me. After deeper investigation, they
were not as major as I thought they were, due to a signed compared to
an unsigned that prevented a negative number from doing actual harm.
The two bigger bugs:
- Mask the ring buffer data page length. There are data flags at the
high bits of the length field. These were not cleared via the
length function, and the length could return a negative number.
(Although the number returned was unsigned, but was assigned to a
signed number) Luckily, this value was compared to PAGE_SIZE which is
unsigned and kept it from entering the path that could have caused damage.
- Check the page usage before reusing the ring buffer reader page.
TCP increments the page ref when passing the page off to the network.
The page is passed back to the ring buffer for use on free. But
the page could still be in use by the TCP stack.
Minor bugs:
- Related to the first bug. No need to clear out the unused ring buffer
data before sending to user space. It is now done by the ring buffer
code itself.
- Reset pointers after free on error path. There were some cases in
the error path that pointers were freed but not set to NULL, and could
have them freed again, having a pointer freed twice.
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Merge tag 'trace-v4.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"While doing tests on tracing over the network, I found that the
packets were getting corrupted.
In the process I found three bugs.
One was the culprit, but the other two scared me. After deeper
investigation, they were not as major as I thought they were, due to a
signed compared to an unsigned that prevented a negative number from
doing actual harm.
The two bigger bugs:
- Mask the ring buffer data page length. There are data flags at the
high bits of the length field. These were not cleared via the
length function, and the length could return a negative number.
(Although the number returned was unsigned, but was assigned to a
signed number) Luckily, this value was compared to PAGE_SIZE which
is unsigned and kept it from entering the path that could have
caused damage.
- Check the page usage before reusing the ring buffer reader page.
TCP increments the page ref when passing the page off to the
network. The page is passed back to the ring buffer for use on
free. But the page could still be in use by the TCP stack.
Minor bugs:
- Related to the first bug. No need to clear out the unused ring
buffer data before sending to user space. It is now done by the
ring buffer code itself.
- Reset pointers after free on error path. There were some cases in
the error path that pointers were freed but not set to NULL, and
could have them freed again, having a pointer freed twice"
* tag 'trace-v4.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix possible double free on failure of allocating trace buffer
tracing: Fix crash when it fails to alloc ring buffer
ring-buffer: Do no reuse reader page if still in use
tracing: Remove extra zeroing out of the ring buffer page
ring-buffer: Mask out the info bits when returning buffer page length
Jing Xia and Chunyan Zhang reported that on failing to allocate part of the
tracing buffer, memory is freed, but the pointers that point to them are not
initialized back to NULL, and later paths may try to free the freed memory
again. Jing and Chunyan fixed one of the locations that does this, but
missed a spot.
Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com
Cc: stable@vger.kernel.org
Fixes: 737223fbca ("tracing: Consolidate buffer allocation code")
Reported-by: Jing Xia <jing.xia@spreadtrum.com>
Reported-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Double free of the ring buffer happens when it fails to alloc new
ring buffer instance for max_buffer if TRACER_MAX_TRACE is configured.
The root cause is that the pointer is not set to NULL after the buffer
is freed in allocate_trace_buffers(), and the freeing of the ring
buffer is invoked again later if the pointer is not equal to Null,
as:
instance_mkdir()
|-allocate_trace_buffers()
|-allocate_trace_buffer(tr, &tr->trace_buffer...)
|-allocate_trace_buffer(tr, &tr->max_buffer...)
// allocate fail(-ENOMEM),first free
// and the buffer pointer is not set to null
|-ring_buffer_free(tr->trace_buffer.buffer)
// out_free_tr
|-free_trace_buffers()
|-free_trace_buffer(&tr->trace_buffer);
//if trace_buffer is not null, free again
|-ring_buffer_free(buf->buffer)
|-rb_free_cpu_buffer(buffer->buffers[cpu])
// ring_buffer_per_cpu is null, and
// crash in ring_buffer_per_cpu->pages
Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com
Cc: stable@vger.kernel.org
Fixes: 737223fbca ("tracing: Consolidate buffer allocation code")
Signed-off-by: Jing Xia <jing.xia@spreadtrum.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
To free the reader page that is allocated with ring_buffer_alloc_read_page(),
ring_buffer_free_read_page() must be called. For faster performance, this
page can be reused by the ring buffer to avoid having to free and allocate
new pages.
The issue arises when the page is used with a splice pipe into the
networking code. The networking code may up the page counter for the page,
and keep it active while sending it is queued to go to the network. The
incrementing of the page ref does not prevent it from being reused in the
ring buffer, and this can cause the page that is being sent out to the
network to be modified before it is sent by reading new data.
Add a check to the page ref counter, and only reuse the page if it is not
being used anywhere else.
Cc: stable@vger.kernel.org
Fixes: 73a757e631 ("ring-buffer: Return reader page back into existing ring buffer")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The ring_buffer_read_page() takes care of zeroing out any extra data in the
page that it returns. There's no need to zero it out again from the
consumer. It was removed from one consumer of this function, but
read_buffers_splice_read() did not remove it, and worse, it contained a
nasty bug because of it.
Cc: stable@vger.kernel.org
Fixes: 2711ca237a ("ring-buffer: Move zeroing out excess in page to ring buffer code")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Two info bits were added to the "commit" part of the ring buffer data page
when returned to be consumed. This was to inform the user space readers that
events have been missed, and that the count may be stored at the end of the
page.
What wasn't handled, was the splice code that actually called a function to
return the length of the data in order to zero out the rest of the page
before sending it up to user space. These data bits were returned with the
length making the value negative, and that negative value was not checked.
It was compared to PAGE_SIZE, and only used if the size was less than
PAGE_SIZE. Luckily PAGE_SIZE is unsigned long which made the compare an
unsigned compare, meaning the negative size value did not end up causing a
large portion of memory to be randomly zeroed out.
Cc: stable@vger.kernel.org
Fixes: 66a8cb95ed ("ring-buffer: Add place holder recording of dropped events")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull x86 PTI preparatory patches from Thomas Gleixner:
"Todays Advent calendar window contains twentyfour easy to digest
patches. The original plan was to have twenty three matching the date,
but a late fixup made that moot.
- Move the cpu_entry_area mapping out of the fixmap into a separate
address space. That's necessary because the fixmap becomes too big
with NRCPUS=8192 and this caused already subtle and hard to
diagnose failures.
The top most patch is fresh from today and cures a brain slip of
that tall grumpy german greybeard, who ignored the intricacies of
32bit wraparounds.
- Limit the number of CPUs on 32bit to 64. That's insane big already,
but at least it's small enough to prevent address space issues with
the cpu_entry_area map, which have been observed and debugged with
the fixmap code
- A few TLB flush fixes in various places plus documentation which of
the TLB functions should be used for what.
- Rename the SYSENTER stack to CPU_ENTRY_AREA stack as it is used for
more than sysenter now and keeping the name makes backtraces
confusing.
- Prevent LDT inheritance on exec() by moving it to arch_dup_mmap(),
which is only invoked on fork().
- Make vysycall more robust.
- A few fixes and cleanups of the debug_pagetables code. Check
PAGE_PRESENT instead of checking the PTE for 0 and a cleanup of the
C89 initialization of the address hint array which already was out
of sync with the index enums.
- Move the ESPFIX init to a different place to prepare for PTI.
- Several code moves with no functional change to make PTI
integration simpler and header files less convoluted.
- Documentation fixes and clarifications"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
x86/cpu_entry_area: Prevent wraparound in setup_cpu_entry_area_ptes() on 32bit
init: Invoke init_espfix_bsp() from mm_init()
x86/cpu_entry_area: Move it out of the fixmap
x86/cpu_entry_area: Move it to a separate unit
x86/mm: Create asm/invpcid.h
x86/mm: Put MMU to hardware ASID translation in one place
x86/mm: Remove hard-coded ASID limit checks
x86/mm: Move the CR3 construction functions to tlbflush.h
x86/mm: Add comments to clarify which TLB-flush functions are supposed to flush what
x86/mm: Remove superfluous barriers
x86/mm: Use __flush_tlb_one() for kernel memory
x86/microcode: Dont abuse the TLB-flush interface
x86/uv: Use the right TLB-flush API
x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack
x86/doc: Remove obvious weirdnesses from the x86 MM layout documentation
x86/mm/64: Improve the memory map documentation
x86/ldt: Prevent LDT inheritance on exec
x86/ldt: Rework locking
arch, mm: Allow arch_dup_mmap() to fail
x86/vsyscall/64: Warn and fail vsyscall emulation in NATIVE mode
...
In order to sanitize the LDT initialization on x86 arch_dup_mmap() must be
allowed to fail. Fix up all instances.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: dan.j.williams@intel.com
Cc: hughd@google.com
Cc: keescook@google.com
Cc: kirill.shutemov@linux.intel.com
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull networking fixes from David Miller"
"What's a holiday weekend without some networking bug fixes? [1]
1) Fix some eBPF JIT bugs wrt. SKB pointers across helper function
calls, from Daniel Borkmann.
2) Fix regression from errata limiting change to marvell PHY driver,
from Zhao Qiang.
3) Fix u16 overflow in SCTP, from Xin Long.
4) Fix potential memory leak during bridge newlink, from Nikolay
Aleksandrov.
5) Fix BPF selftest build on s390, from Hendrik Brueckner.
6) Don't append to cfg80211 automatically generated certs file,
always write new ones from scratch. From Thierry Reding.
7) Fix sleep in atomic in mac80211 hwsim, from Jia-Ju Bai.
8) Fix hang on tg3 MTU change with certain chips, from Brian King.
9) Add stall detection to arc emac driver and reset chip when this
happens, from Alexander Kochetkov.
10) Fix MTU limitng in GRE tunnel drivers, from Xin Long.
11) Fix stmmac timestamping bug due to mis-shifting of field. From
Fredrik Hallenberg.
12) Fix metrics match when deleting an ipv4 route. The kernel sets
some internal metrics bits which the user isn't going to set when
it makes the delete request. From Phil Sutter.
13) mvneta driver loop over RX queues limits on "txq_number" :-) Fix
from Yelena Krivosheev.
14) Fix double free and memory corruption in get_net_ns_by_id, from
Eric W. Biederman.
15) Flush ipv4 FIB tables in the reverse order. Some tables can share
their actual backing data, in particular this happens for the MAIN
and LOCAL tables. We have to kill the LOCAL table first, because
it uses MAIN's backing memory. Fix from Ido Schimmel.
16) Several eBPF verifier value tracking fixes, from Edward Cree, Jann
Horn, and Alexei Starovoitov.
17) Make changes to ipv6 autoflowlabel sysctl really propagate to
sockets, unless the socket has set the per-socket value
explicitly. From Shaohua Li.
18) Fix leaks and double callback invocations of zerocopy SKBs, from
Willem de Bruijn"
[1] Is this a trick question? "Relaxing"? "Quiet"? "Fine"? - Linus.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (77 commits)
skbuff: skb_copy_ubufs must release uarg even without user frags
skbuff: orphan frags before zerocopy clone
net: reevalulate autoflowlabel setting after sysctl setting
openvswitch: Fix pop_vlan action for double tagged frames
ipv6: Honor specified parameters in fibmatch lookup
bpf: do not allow root to mangle valid pointers
selftests/bpf: add tests for recent bugfixes
bpf: fix integer overflows
bpf: don't prune branches when a scalar is replaced with a pointer
bpf: force strict alignment checks for stack pointers
bpf: fix missing error return in check_stack_boundary()
bpf: fix 32-bit ALU op verification
bpf: fix incorrect tracking of register size truncation
bpf: fix incorrect sign extension in check_alu_op()
bpf/verifier: fix bounds calculation on BPF_RSH
ipv4: Fix use-after-free when flushing FIB tables
s390/qeth: fix error handling in checksum cmd callback
tipc: remove joining group member from congested list
selftests: net: Adding config fragment CONFIG_NUMA=y
nfp: bpf: keep track of the offloaded program
...
Do not allow root to convert valid pointers into unknown scalars.
In particular disallow:
ptr &= reg
ptr <<= reg
ptr += ptr
and explicitly allow:
ptr -= ptr
since pkt_end - pkt == length
1.
This minimizes amount of address leaks root can do.
In the future may need to further tighten the leaks with kptr_restrict.
2.
If program has such pointer math it's likely a user mistake and
when verifier complains about it right away instead of many instructions
later on invalid memory access it's easier for users to fix their progs.
3.
when register holding a pointer cannot change to scalar it allows JITs to
optimize better. Like 32-bit archs could use single register for pointers
instead of a pair required to hold 64-bit scalars.
4.
reduces architecture dependent behavior. Since code:
r1 = r10;
r1 &= 0xff;
if (r1 ...)
will behave differently arm64 vs x64 and offloaded vs native.
A significant chunk of ptr mangling was allowed by
commit f1174f77b5 ("bpf/verifier: rework value tracking")
yet some of it was allowed even earlier.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
There were various issues related to the limited size of integers used in
the verifier:
- `off + size` overflow in __check_map_access()
- `off + reg->off` overflow in check_mem_access()
- `off + reg->var_off.value` overflow or 32-bit truncation of
`reg->var_off.value` in check_mem_access()
- 32-bit truncation in check_stack_boundary()
Make sure that any integer math cannot overflow by not allowing
pointer math with large values.
Also reduce the scope of "scalar op scalar" tracking.
Fixes: f1174f77b5 ("bpf/verifier: rework value tracking")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This could be made safe by passing through a reference to env and checking
for env->allow_ptr_leaks, but it would only work one way and is probably
not worth the hassle - not doing it will not directly lead to program
rejection.
Fixes: f1174f77b5 ("bpf/verifier: rework value tracking")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Force strict alignment checks for stack pointers because the tracking of
stack spills relies on it; unaligned stack accesses can lead to corruption
of spilled registers, which is exploitable.
Fixes: f1174f77b5 ("bpf/verifier: rework value tracking")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
32-bit ALU ops operate on 32-bit values and have 32-bit outputs.
Adjust the verifier accordingly.
Fixes: f1174f77b5 ("bpf/verifier: rework value tracking")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Properly handle register truncation to a smaller size.
The old code first mirrors the clearing of the high 32 bits in the bitwise
tristate representation, which is correct. But then, it computes the new
arithmetic bounds as the intersection between the old arithmetic bounds and
the bounds resulting from the bitwise tristate representation. Therefore,
when coerce_reg_to_32() is called on a number with bounds
[0xffff'fff8, 0x1'0000'0007], the verifier computes
[0xffff'fff8, 0xffff'ffff] as bounds of the truncated number.
This is incorrect: The truncated number could also be in the range [0, 7],
and no meaningful arithmetic bounds can be computed in that case apart from
the obvious [0, 0xffff'ffff].
Starting with v4.14, this is exploitable by unprivileged users as long as
the unprivileged_bpf_disabled sysctl isn't set.
Debian assigned CVE-2017-16996 for this issue.
v2:
- flip the mask during arithmetic bounds calculation (Ben Hutchings)
v3:
- add CVE number (Ben Hutchings)
Fixes: b03c9f9fdc ("bpf/verifier: track signed and unsigned min/max values")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Distinguish between
BPF_ALU64|BPF_MOV|BPF_K (load 32-bit immediate, sign-extended to 64-bit)
and BPF_ALU|BPF_MOV|BPF_K (load 32-bit immediate, zero-padded to 64-bit);
only perform sign extension in the first case.
Starting with v4.14, this is exploitable by unprivileged users as long as
the unprivileged_bpf_disabled sysctl isn't set.
Debian assigned CVE-2017-16995 for this issue.
v3:
- add CVE number (Ben Hutchings)
Fixes: 484611357c ("bpf: allow access into map value arrays")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Incorrect signed bounds were being computed.
If the old upper signed bound was positive and the old lower signed bound was
negative, this could cause the new upper signed bound to be too low,
leading to security issues.
Fixes: b03c9f9fdc ("bpf/verifier: track signed and unsigned min/max values")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
[jannh@google.com: changed description to reflect bug impact]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Daniel Borkmann says:
====================
pull-request: bpf 2017-12-17
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) Fix a corner case in generic XDP where we have non-linear skbs
but enough tailroom in the skb to not miss to linearizing there,
from Song.
2) Fix BPF JIT bugs in s390x and ppc64 to not recache skb data when
BPF context is not skb, from Daniel.
3) Fix a BPF JIT bug in sparc64 where recaching skb data after helper
call would use the wrong register for the skb, from Daniel.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
CONFIG_NO_HZ_FULL doesn't make sense without CONFIG_CPU_ISOLATION. In
fact enabling the first without the second is a regression as nohz_full=
boot parameter gets silently ignored.
Besides this unnatural combination hangs RCU gp kthread when running
rcutorture for reasons that are not yet fully understood:
rcu_preempt kthread starved for 9974 jiffies! g4294967208
+c4294967207 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=0
rcu_preempt I 7464 8 2 0x80000000
Call Trace:
__schedule+0x493/0x620
schedule+0x24/0x40
schedule_timeout+0x330/0x3b0
? preempt_count_sub+0xea/0x140
? collect_expired_timers+0xb0/0xb0
rcu_gp_kthread+0x6bf/0xef0
This commit therefore makes NO_HZ_FULL select CPU_ISOLATION, which
prevents all these bad behaviours.
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <kernellwp@gmail.com>
Fixes: 5c4991e24c ("sched/isolation: Split out new CONFIG_CPU_ISOLATION=y config from CONFIG_NO_HZ_FULL")
Link: http://lkml.kernel.org/r/1513275507-29200-2-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull timer fix from Thomas Gleixner:
"A single bugfix which prevents arbitrary sigev_notify values in
posix-timers"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
posix-timer: Properly check sigevent->sigev_notify
[ Note, this is a Git cherry-pick of the following commit:
506458efaf ("locking/barriers: Convert users of lockless_dereference() to READ_ONCE()")
... for easier x86 PTI code testing and back-porting. ]
READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull networking fixes from David Miller:
1) Clamp timeouts to INT_MAX in conntrack, from Jay Elliot.
2) Fix broken UAPI for BPF_PROG_TYPE_PERF_EVENT, from Hendrik
Brueckner.
3) Fix locking in ieee80211_sta_tear_down_BA_sessions, from Johannes
Berg.
4) Add missing barriers to ptr_ring, from Michael S. Tsirkin.
5) Don't advertise gigabit in sh_eth when not available, from Thomas
Petazzoni.
6) Check network namespace when delivering to netlink taps, from Kevin
Cernekee.
7) Kill a race in raw_sendmsg(), from Mohamed Ghannam.
8) Use correct address in TCP md5 lookups when replying to an incoming
segment, from Christoph Paasch.
9) Add schedule points to BPF map alloc/free, from Eric Dumazet.
10) Don't allow silly mtu values to be used in ipv4/ipv6 multicast, also
from Eric Dumazet.
11) Fix SKB leak in tipc, from Jon Maloy.
12) Disable MAC learning on OVS ports of mlxsw, from Yuval Mintz.
13) SKB leak fix in skB_complete_tx_timestamp(), from Willem de Bruijn.
14) Add some new qmi_wwan device IDs, from Daniele Palmas.
15) Fix static key imbalance in ingress qdisc, from Jiri Pirko.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (76 commits)
net: qcom/emac: Reduce timeout for mdio read/write
net: sched: fix static key imbalance in case of ingress/clsact_init error
net: sched: fix clsact init error path
ip_gre: fix wrong return value of erspan_rcv
net: usb: qmi_wwan: add Telit ME910 PID 0x1101 support
pkt_sched: Remove TC_RED_OFFLOADED from uapi
net: sched: Move to new offload indication in RED
net: sched: Add TCA_HW_OFFLOAD
net: aquantia: Increment driver version
net: aquantia: Fix typo in ethtool statistics names
net: aquantia: Update hw counters on hw init
net: aquantia: Improve link state and statistics check interval callback
net: aquantia: Fill in multicast counter in ndev stats from hardware
net: aquantia: Fill ndev stat couters from hardware
net: aquantia: Extend stat counters to 64bit values
net: aquantia: Fix hardware DMA stream overload on large MRRS
net: aquantia: Fix actual speed capabilities reporting
sock: free skb in skb_complete_tx_timestamp on error
s390/qeth: update takeover IPs after configuration change
s390/qeth: lock IP table while applying takeover changes
...
Pull locking fixes from Ingo Molnar:
"Misc fixes:
- Fix a S390 boot hang that was caused by the lock-break logic.
Remove lock-break to begin with, as review suggested it was
unreasonably fragile and our confidence in its continued good
health is lower than our confidence in its removal.
- Remove the lockdep cross-release checking code for now, because of
unresolved false positive warnings. This should make lockdep work
well everywhere again.
- Get rid of the final (and single) ACCESS_ONCE() straggler and
remove the API from v4.15.
- Fix a liblockdep build warning"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tools/lib/lockdep: Add missing declaration of 'pr_cont()'
checkpatch: Remove ACCESS_ONCE() warning
compiler.h: Remove ACCESS_ONCE()
tools/include: Remove ACCESS_ONCE()
tools/perf: Convert ACCESS_ONCE() to READ_ONCE()
locking/lockdep: Remove the cross-release locking checks
locking/core: Remove break_lock field when CONFIG_GENERIC_LOCKBREAK=y
locking/core: Fix deadlock during boot on systems with GENERIC_LOCKBREAK
Pull scheduler fixes from Ingo Molnar:
"Two fixes: a crash fix for an ARM SoC platform, and kernel-doc
warnings fixes"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/rt: Do not pull from current CPU if only one CPU to pull
sched/core: Fix kernel-doc warnings after code movement
Some JITs don't cache skb context on stack in prologue, so when
LD_ABS/IND is used and helper calls yield bpf_helper_changes_pkt_data()
as true, then they temporarily save/restore skb pointer. However,
the assumption that skb always has to be in r1 is a bit of a
gamble. Right now it turned out to be true for all helpers listed
in bpf_helper_changes_pkt_data(), but lets enforce that from verifier
side, so that we make this a guarantee and bail out if the func
proto is misconfigured in future helpers.
In case of BPF helper calls from cBPF, bpf_helper_changes_pkt_data()
is completely unrelevant here (since cBPF is context read-only) and
therefore always false.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Wagner reported a crash on the BeagleBone Black SoC.
This is a single CPU architecture, and does not have a functional
arch_send_call_function_single_ipi() implementation which can crash
the kernel if that is called.
As it only has one CPU, it shouldn't be called, but if the kernel is
compiled for SMP, the push/pull RT scheduling logic now calls it for
irq_work if the one CPU is overloaded, it can use that function to call
itself and crash the kernel.
Ideally, we should disable the SCHED_FEAT(RT_PUSH_IPI) if the system
only has a single CPU. But SCHED_FEAT is a constant if sched debugging
is turned off. Another fix can also be used, and this should also help
with normal SMP machines. That is, do not initiate the pull code if
there's only one RT overloaded CPU, and that CPU happens to be the
current CPU that is scheduling in a lower priority task.
Even on a system with many CPUs, if there's many RT tasks waiting to
run on a single CPU, and that CPU schedules in another RT task of lower
priority, it will initiate the PULL logic in case there's a higher
priority RT task on another CPU that is waiting to run. But if there is
no other CPU with waiting RT tasks, it will initiate the RT pull logic
on itself (as it still has RT tasks waiting to run). This is a wasted
effort.
Not only does this help with SMP code where the current CPU is the only
one with RT overloaded tasks, it should also solve the issue that
Daniel encountered, because it will prevent the PULL logic from
executing, as there's only one CPU on the system, and the check added
here will cause it to exit the RT pull code.
Reported-by: Daniel Wagner <wagi@monom.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: 4bdced5c9 ("sched/rt: Simplify the IPI based RT balancing logic")
Link: http://lkml.kernel.org/r/20171202130454.4cbbfe8d@vmware.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
timer_create() specifies via sigevent->sigev_notify the signal delivery for
the new timer. The valid modes are SIGEV_NONE, SIGEV_SIGNAL, SIGEV_THREAD
and (SIGEV_SIGNAL | SIGEV_THREAD_ID).
The sanity check in good_sigevent() is only checking the valid combination
for the SIGEV_THREAD_ID bit, i.e. SIGEV_SIGNAL, but if SIGEV_THREAD_ID is
not set it accepts any random value.
This has no real effects on the posix timer and signal delivery code, but
it affects show_timer() which handles the output of /proc/$PID/timers. That
function uses a string array to pretty print sigev_notify. The access to
that array has no bound checks, so random sigev_notify cause access beyond
the array bounds.
Add proper checks for the valid notify modes and remove the SIGEV_THREAD_ID
masking from various code pathes as SIGEV_NONE can never be set in
combination with SIGEV_THREAD_ID.
Reported-by: Eric Biggers <ebiggers3@gmail.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: stable@vger.kernel.org
- Comment fixes
- Build fix
- Better memory alloction (don't use NR_CPUS)
- Configuration fix
- Build warning fix
- Enhanced callback parameter (to simplify users of trace hooks)
- Give up on stack tracing when RCU isn't watching (it's a lost cause)
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Merge tag 'trace-v4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Various fix-ups:
- comment fixes
- build fix
- better memory alloction (don't use NR_CPUS)
- configuration fix
- build warning fix
- enhanced callback parameter (to simplify users of trace hooks)
- give up on stack tracing when RCU isn't watching (it's a lost
cause)"
* tag 'trace-v4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Have stack trace not record if RCU is not watching
tracing: Pass export pointer as argument to ->write()
ring-buffer: Remove unused function __rb_data_page_index()
tracing: make PREEMPTIRQ_EVENTS depend on TRACING
tracing: Allocate mask_str buffer dynamically
tracing: always define trace_{irq,preempt}_{enable_disable}
tracing: Fix code comments in trace.c
The stack tracer records a stack dump whenever it sees a stack usage that is
more than what it ever saw before. This can happen at any function that is
being traced. If it happens when the CPU is going idle (or other strange
locations), RCU may not be watching, and in this case, the recording of the
stack trace will trigger a warning. There's been lots of efforts to make
hacks to allow stack tracing to proceed even if RCU is not watching, but
this only causes more issues to appear. Simply do not trace a stack if RCU
is not watching. It probably isn't a bad stack anyway.
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
gcc toggle -fisolate-erroneous-paths-dereference (default at -O2
onwards) isolates faulty code paths such as null pointer access, divide
by zero etc. If gcc port doesnt implement __builtin_trap, an abort() is
generated which causes kernel link error.
In this case, gcc is generating abort due to 'divide by zero' in
lib/mpi/mpih-div.c.
Currently 'frv' and 'arc' are failing. Previously other arch was also
broken like m32r was fixed by commit d22e3d69ee ("m32r: fix build
failure").
Let's define this weak function which is common for all arch and fix the
problem permanently. We can even remove the arch specific 'abort' after
this is done.
Link: http://lkml.kernel.org/r/1513118956-8718-1-git-send-email-sudipm.mukherjee@gmail.com
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In testing, we found that nfsd threads may call set_groups in parallel
for the same entry cached in auth.unix.gid, racing in the call of
groups_sort, corrupting the groups for that entry and leading to
permission denials for the client.
This patch:
- Make groups_sort globally visible.
- Move the call to groups_sort to the modifiers of group_info
- Remove the call to groups_sort from set_groups
Link: http://lkml.kernel.org/r/20171211151420.18655-1-thiago.becker@gmail.com
Signed-off-by: Thiago Rafael Becker <thiago.becker@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds