Vince Weaver reported:
> I was tracking down some regressions in my perf_event_test testsuite.
> Some of the tests broke in the 4.11-rc1 timeframe.
>
> I've bisected one of them, this report is about
> tests/overflow/simul_oneshot_group_overflow
> This test creates an event group containing two sampling events, set
> to overflow to a signal handler (which disables and then refreshes the
> event).
>
> On a good kernel you get the following:
> Event perf::instructions with period 1000000
> Event perf::instructions with period 2000000
> fd 3 overflows: 946 (perf::instructions/1000000)
> fd 4 overflows: 473 (perf::instructions/2000000)
> Ending counts:
> Count 0: 946379875
> Count 1: 946365218
>
> With the broken kernels you get:
> Event perf::instructions with period 1000000
> Event perf::instructions with period 2000000
> fd 3 overflows: 938 (perf::instructions/1000000)
> fd 4 overflows: 318 (perf::instructions/2000000)
> Ending counts:
> Count 0: 946373080
> Count 1: 653373058
The root cause of the bug is that the following commit:
487f05e18a ("perf/core: Optimize event rescheduling on active contexts")
erronously assumed that event's 'pinned' setting determines whether the
event belongs to a pinned group or not, but in fact, it's the group
leader's pinned state that matters.
This was discovered by Vince in the test case described above, where two instruction
counters are grouped, the group leader is pinned, but the other event is not;
in the regressed case the counters were off by 33% (the difference between events'
periods), but should be the same within the error margin.
Fix the problem by looking at the group leader's pinning.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 487f05e18a ("perf/core: Optimize event rescheduling on active contexts")
Link: http://lkml.kernel.org/r/87lgnmvw7h.fsf@ashishki-desk.ger.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
randstruct plugin, including the task_struct.
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Merge tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull structure randomization updates from Kees Cook:
"Now that IPC and other changes have landed, enable manual markings for
randstruct plugin, including the task_struct.
This is the rest of what was staged in -next for the gcc-plugins, and
comes in three patches, largest first:
- mark "easy" structs with __randomize_layout
- mark task_struct with an optional anonymous struct to isolate the
__randomize_layout section
- mark structs to opt _out_ of automated marking (which will come
later)
And, FWIW, this continues to pass allmodconfig (normal and patched to
enable gcc-plugins) builds of x86_64, i386, arm64, arm, powerpc, and
s390 for me"
* tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
randstruct: opt-out externally exposed function pointer structs
task_struct: Allow randomized layout
randstruct: Mark various structs for randomization
The combination of WQ_UNBOUND and max_active == 1 used to imply
ordered execution. After NUMA affinity 4c16bd327c74 ("workqueue:
implement NUMA affinity for unbound workqueues"), this is no longer
true due to per-node worker pools.
While the right way to create an ordered workqueue is
alloc_ordered_workqueue(), the documentation has been misleading for a
long time and people do use WQ_UNBOUND and max_active == 1 for ordered
workqueues which can lead to subtle bugs which are very difficult to
trigger.
It's unlikely that we'd see noticeable performance impact by enforcing
ordering on WQ_UNBOUND / max_active == 1 workqueues. Let's
automatically set __WQ_ORDERED for those workqueues.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Christoph Hellwig <hch@infradead.org>
Reported-by: Alexei Potashnik <alexei@purestorage.com>
Fixes: 4c16bd327c74 ("workqueue: implement NUMA affinity for unbound workqueues")
Cc: stable@vger.kernel.org # v3.10+
ftrace can fail to allocate per-CPU ring buffer on systems with a large
number of CPUs coupled while large amounts of cache happening in the
page cache. Currently the ring buffer allocation doesn't retry in the VM
implementation even if direct-reclaim made some progress but still
wasn't able to find a free page. On retrying I see that the allocations
almost always succeed. The retry doesn't happen because __GFP_NORETRY is
used in the tracer to prevent the case where we might OOM, however if we
drop __GFP_NORETRY, we risk destabilizing the system if OOM killer is
triggered. To prevent this situation, use the __GFP_RETRY_MAYFAIL flag
introduced recently [1].
Tested the following still succeeds without destabilizing a system with
1GB memory.
echo 300000 > /sys/kernel/debug/tracing/buffer_size_kb
[1] https://marc.info/?l=linux-mm&m=149820805124906&w=2
Link: http://lkml.kernel.org/r/20170713021416.8897-1-joelaf@google.com
Cc: Tim Murray <timmurray@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
On subsystem registration, css_populate_dir() is not called on the new
root css, so the interface files for the subsystem on cgrp_dfl_root
aren't created on registration. This is a residue from the days when
cgrp_dfl_root was used only as the parking spot for unused subsystems,
which no longer is true as it's used as the root for cgroup2.
This is often fine as later operations tend to create them as a part
of mount (cgroup1) or subtree_control operations (cgroup2); however,
it's not difficult to mount cgroup2 with the controller interface
files missing as Waiman found out.
Fix it by invoking css_populate_dir() on the root css on subsys
registration.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Waiman Long <longman@redhat.com>
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: Tejun Heo <tj@kernel.org>
Interrupts with the IRQF_FORCE_RESUME flag set have also the
IRQF_NO_SUSPEND flag set. They are not disabled in the suspend path, but
must be forcefully resumed. That's used by XEN to keep IPIs enabled beyond
the suspension of device irqs. Force resume works by pretending that the
interrupt was disabled and then calling __irq_enable().
Incrementing the disabled depth counter was enough to do that, but with the
recent changes which use state flags to avoid unnecessary hardware access,
this is not longer sufficient. If the state flags are not set, then the
hardware callbacks are not invoked and the interrupt line stays disabled in
"hardware".
Set the disabled and masked state when pretending that an interrupt got
disabled by suspend.
Fixes: bf22ff45bed6 ("genirq: Avoid unnecessary low level irq function calls")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: boris.ostrovsky@oracle.com
Link: http://lkml.kernel.org/r/20170717174703.4603-2-jgross@suse.com
Pull irq fix from Thomas Gleixner:
"Fix the fallout from reworking the locking and resource management in
request/free_irq()"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq: Keep chip buslock across irq_request/release_resources()
Pull SMP fix from Thomas Gleixner:
"Replace the bogus BUG_ON in the cpu hotplug code"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
smp/hotplug: Replace BUG_ON and react useful
The BPF map devmap holds a refcnt on the net_device structure when
it is in the map. We need to do this to ensure on driver unload we
don't lose a dev reference.
However, its not very convenient to have to manually unload the map
when destroying a net device so add notifier handlers to do the cleanup
automatically. But this creates a race between update/destroy BPF
syscall and programs and the unregister netdev hook.
Unfortunately, the best I could come up with is either to live with
requiring manual removal of net devices from the map before removing
the net device OR to add a mutex in devmap to ensure the map is not
modified while we are removing a device. The fallout also requires
that BPF programs no longer update/delete the map from the BPF program
side because the mutex may sleep and this can not be done from inside
an rcu critical section. This is not a real problem though because I
have not come up with any use cases where this is actually useful in
practice. If/when we come up with a compelling user for this we may
need to revisit this.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For performance reasons we want to avoid updating the tail pointer in
the driver tx ring as much as possible. To accomplish this we add
batching support to the redirect path in XDP.
This adds another ndo op "xdp_flush" that is used to inform the driver
that it should bump the tail pointer on the TX ring.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
BPF programs can use the devmap with a bpf_redirect_map() helper
routine to forward packets to netdevice in map.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Device map (devmap) is a BPF map, primarily useful for networking
applications, that uses a key to lookup a reference to a netdevice.
The map provides a clean way for BPF programs to build virtual port
to physical port maps. Additionally, it provides a scoping function
for the redirect action itself allowing multiple optimizations. Future
patches will leverage the map to provide batching at the XDP layer.
Another optimization/feature, that is not yet implemented, would be
to support multiple netdevices per key to support efficient multicast
and broadcast support.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull ->s_options removal from Al Viro:
"Preparations for fsmount/fsopen stuff (coming next cycle). Everything
gets moved to explicit ->show_options(), killing ->s_options off +
some cosmetic bits around fs/namespace.c and friends. Basically, the
stuff needed to work with fsmount series with minimum of conflicts
with other work.
It's not strictly required for this merge window, but it would reduce
the PITA during the coming cycle, so it would be nice to have those
bits and pieces out of the way"
* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
isofs: Fix isofs_show_options()
VFS: Kill off s_options and helpers
orangefs: Implement show_options
9p: Implement show_options
isofs: Implement show_options
afs: Implement show_options
affs: Implement show_options
befs: Implement show_options
spufs: Implement show_options
bpf: Implement show_options
ramfs: Implement show_options
pstore: Implement show_options
omfs: Implement show_options
hugetlbfs: Implement show_options
VFS: Don't use save/replace_mount_options if not using generic_show_options
VFS: Provide empty name qstr
VFS: Make get_filesystem() return the affected filesystem
VFS: Clean up whitespace in fs/namespace.c and fs/super.c
Provide a function to create a NUL-terminated string from unterminated data
- Avoid clearing the PCI PME Enable bit for devices as a result of
config space restoration which confuses AML executed afterward and
causes wakeup events to be lost on some systems (Rafael Wysocki).
- Fix the native PCIe PME interrupts handling in the cases when the
PME IRQ is set up as a system wakeup one so that runtime PM remote
wakeup works as expected after system resume on systems where that
happens (Rafael Wysocki).
- Fix the device PM QoS sysfs interface to handle invalid user input
correctly instead of using an unititialized variable value as the
latency tolerance for the device at hand (Dan Carpenter).
- Get rid of one more rounding error from intel_pstate computations
(Srinivas Pandruvada).
- Fix the schedutil cpufreq governor to prevent it from possibly
accessing unititialized data structures from governor callbacks in
some cases on systems when multiple CPUs share a single cpufreq
policy object (Vikram Mulukutla).
- Fix the return values of probe routines in two devfreq drivers
(Gustavo Silva).
- Constify an attribute_group structure in devfreq (Arvind Yadav).
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Merge tag 'pm-fixes-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix a recently exposed issue in the PCI device wakeup code and
one older problem related to PCI device wakeup that has been reported
recently, modify one more piece of computations in intel_pstate to get
rid of a rounding error, fix a possible race in the schedutil cpufreq
governor, fix the device PM QoS sysfs interface to correctly handle
invalid user input, fix return values of two probe routines in devfreq
drivers and constify an attribute_group structure in devfreq.
Specifics:
- Avoid clearing the PCI PME Enable bit for devices as a result of
config space restoration which confuses AML executed afterward and
causes wakeup events to be lost on some systems (Rafael Wysocki).
- Fix the native PCIe PME interrupts handling in the cases when the
PME IRQ is set up as a system wakeup one so that runtime PM remote
wakeup works as expected after system resume on systems where that
happens (Rafael Wysocki).
- Fix the device PM QoS sysfs interface to handle invalid user input
correctly instead of using an unititialized variable value as the
latency tolerance for the device at hand (Dan Carpenter).
- Get rid of one more rounding error from intel_pstate computations
(Srinivas Pandruvada).
- Fix the schedutil cpufreq governor to prevent it from possibly
accessing unititialized data structures from governor callbacks in
some cases on systems when multiple CPUs share a single cpufreq
policy object (Vikram Mulukutla).
- Fix the return values of probe routines in two devfreq drivers
(Gustavo Silva).
- Constify an attribute_group structure in devfreq (Arvind Yadav)"
* tag 'pm-fixes-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PCI / PM: Fix native PME handling during system suspend/resume
PCI / PM: Restore PME Enable after config space restoration
cpufreq: schedutil: Fix sugov_start() versus sugov_update_shared() race
PM / QoS: return -EINVAL for bogus strings
cpufreq: intel_pstate: Fix ratio setting for min_perf_pct
PM / devfreq: constify attribute_group structures.
PM / devfreq: tegra: fix error return code in tegra_devfreq_probe()
PM / devfreq: rk3399_dmc: fix error return code in rk3399_dmcfreq_probe()
If we reach the limit of modprobe_limit threads running the next
request_module() call will fail. The original reason for adding a kill
was to do away with possible issues with in old circumstances which would
create a recursive series of request_module() calls.
We can do better than just be super aggressive and reject calls once we've
reached the limit by simply making pending callers wait until the
threshold has been reduced, and then throttling them in, one by one.
This throttling enables requests over the kmod concurrent limit to be
processed once a pending request completes. Only the first item queued up
to wait is woken up. The assumption here is once a task is woken it will
have no other option to also kick the queue to check if there are more
pending tasks -- regardless of whether or not it was successful.
By throttling and processing only max kmod concurrent tasks we ensure we
avoid unexpected fatal request_module() calls, and we keep memory
consumption on module loading to a minimum.
With x86_64 qemu, with 4 cores, 4 GiB of RAM it takes the following run
time to run both tests:
time ./kmod.sh -t 0008
real 0m16.366s
user 0m0.883s
sys 0m8.916s
time ./kmod.sh -t 0009
real 0m50.803s
user 0m0.791s
sys 0m9.852s
Link: http://lkml.kernel.org/r/20170628223155.26472-4-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This comment in the code is incomplete, and I believe it begs a definition of
dl_boosted to make sense of the condition that follows. Rewrite the comment and
also rearrange the condition that follows to reflect the first condition "we
have a top pi-waiter which is a SCHED_DEADLINE task" in that order. Also fix a
typo that follows.
Signed-off-by: Joel Fernandes <joelaf@google.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170713022429.10307-1-joelaf@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Recent kernels trigger this warning:
BUG: using smp_processor_id() in preemptible [00000000] code: 99-trinity/181
caller is debug_smp_processor_id+0x17/0x19
CPU: 0 PID: 181 Comm: 99-trinity Not tainted 4.12.0-01059-g2a42eb9 #1
Call Trace:
dump_stack+0x82/0xb8
check_preemption_disabled()
debug_smp_processor_id()
vtime_delta()
task_cputime()
thread_group_cputime()
thread_group_cputime_adjusted()
wait_consider_task()
do_wait()
SYSC_wait4()
do_syscall_64()
entry_SYSCALL64_slow_path()
As Frederic pointed out:
| Although those sched_clock_cpu() things seem to only matter when the
| sched_clock() is unstable. And that stability is a condition for nohz_full
| to work anyway. So probably sched_clock() alone would be enough.
This patch fixes it by replacing sched_clock_cpu() with sched_clock() to
avoid calling smp_processor_id() in a preemptible context.
Reported-by: Xiaolong Ye <xiaolong.ye@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1499586028-7402-1-git-send-email-wanpeng.li@hotmail.com
[ Prettified the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
- Show the tgid mappings for user space trace tools to use
- Fix and optimize the comm and tgid cache recording
- Sanitize derived kprobe names
- Ftrace selftest updates
- trace file header fix
- Update of Documentation/trace/ftrace.txt
- Compiler warning fixes
- Fix possible uninitialized variable
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Merge tag 'trace-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull more tracing updates from Steven Rostedt:
"A few more minor updates:
- Show the tgid mappings for user space trace tools to use
- Fix and optimize the comm and tgid cache recording
- Sanitize derived kprobe names
- Ftrace selftest updates
- trace file header fix
- Update of Documentation/trace/ftrace.txt
- Compiler warning fixes
- Fix possible uninitialized variable"
* tag 'trace-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Fix uninitialized variable in match_records()
ftrace: Remove an unneeded NULL check
ftrace: Hide cached module code for !CONFIG_MODULES
tracing: Do note expose stack_trace_filter without DYNAMIC_FTRACE
tracing: Update Documentation/trace/ftrace.txt
tracing: Fixup trace file header alignment
selftests/ftrace: Add a testcase for kprobe event naming
selftests/ftrace: Add a test to probe module functions
selftests/ftrace: Update multiple kprobes test for powerpc
trace/kprobes: Sanitize derived event names
tracing: Attempt to record other information even if some fail
tracing: Treat recording tgid for idle task as a success
tracing: Treat recording comm for idle task as a success
tracing: Add saved_tgids file to show cached pid to tgid mappings
Merge yet more updates from Andrew Morton:
- various misc things
- kexec updates
- sysctl core updates
- scripts/gdb udpates
- checkpoint-restart updates
- ipc updates
- kernel/watchdog updates
- Kees's "rough equivalent to the glibc _FORTIFY_SOURCE=1 feature"
- "stackprotector: ascii armor the stack canary"
- more MM bits
- checkpatch updates
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (96 commits)
writeback: rework wb_[dec|inc]_stat family of functions
ARM: samsung: usb-ohci: move inline before return type
video: fbdev: omap: move inline before return type
video: fbdev: intelfb: move inline before return type
USB: serial: safe_serial: move __inline__ before return type
drivers: tty: serial: move inline before return type
drivers: s390: move static and inline before return type
x86/efi: move asmlinkage before return type
sh: move inline before return type
MIPS: SMP: move asmlinkage before return type
m68k: coldfire: move inline before return type
ia64: sn: pci: move inline before type
ia64: move inline before return type
FRV: tlbflush: move asmlinkage before return type
CRIS: gpio: move inline before return type
ARM: HP Jornada 7XX: move inline before return type
ARM: KVM: move asmlinkage before type
checkpatch: improve the STORAGE_CLASS test
mm, migration: do not trigger OOM killer when migrating memory
drm/i915: use __GFP_RETRY_MAYFAIL
...
We don't need to adjust priority before adding a new pi_waiter, the
priority only needs to be updated after pi_waiter change or task
priority change.
Steven Rostedt pointed out:
"Interesting, I did some git mining and this was added with the original
entry of the rtmutex.c (23f78d4a03c5). Looking at even that version, I
don't see the purpose of adjusting the task prio here. It is done
before anything changes in the task."
Signed-off-by: Alex Shi <alex.shi@linaro.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1499926704-28841-1-git-send-email-alex.shi@linaro.org
[ Enhance the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Summary of modules changes for the 4.13 merge window:
- Minor code cleanups
- Avoid accessing mod struct prior to checking module struct version, from Kees
- Fix racy atomic inc/dec logic of kmod_concurrent_max in kmod, from Luis
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"Summary of modules changes for the 4.13 merge window:
- Minor code cleanups
- Avoid accessing mod struct prior to checking module struct version,
from Kees
- Fix racy atomic inc/dec logic of kmod_concurrent_max in kmod, from
Luis"
* tag 'modules-for-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: make the modinfo name const
kmod: reduce atomic operations on kmod_concurrent and simplify
module: use list_for_each_entry_rcu() on find_module_all()
kernel/module.c: suppress warning about unused nowarn variable
module: Add module name to modinfo
module: Pass struct load_info into symbol checks
Use the ascii-armor canary to prevent unterminated C string overflows
from being able to successfully overwrite the canary, even if they
somehow obtain the canary value.
Inspired by execshield ascii-armor and Daniel Micay's linux-hardened
tree.
Link: http://lkml.kernel.org/r/20170524155751.424-3-riel@redhat.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Defining kexec_purgatory as a zero-length char array upsets compile time
size checking. Since this is built on a per-arch basis, define it as an
unsized char array (like is done for other similar things, e.g. linker
sections). This silences the warning generated by the future
CONFIG_FORTIFY_SOURCE, which did not like the memcmp() of a "0 byte"
array. This drops the __weak and uses an extern instead, since both
users define kexec_purgatory.
Link: http://lkml.kernel.org/r/1497903987-21002-4-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After reconfiguring watchdog sysctls etc., architecture specific
watchdogs may not get all their parameters updated.
watchdog_nmi_reconfigure() can be implemented to pull the new values in
and set the arch NMI watchdog.
[npiggin@gmail.com: add code comments]
Link: http://lkml.kernel.org/r/20170617125933.774d3858@roar.ozlabs.ibm.com
[arnd@arndb.de: hide unused function]
Link: http://lkml.kernel.org/r/20170620204854.966601-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170616065715.18390-5-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Split SOFTLOCKUP_DETECTOR from LOCKUP_DETECTOR, and split
HARDLOCKUP_DETECTOR_PERF from HARDLOCKUP_DETECTOR.
LOCKUP_DETECTOR implies the general boot, sysctl, and programming
interfaces for the lockup detectors.
An architecture that wants to use a hard lockup detector must define
HAVE_HARDLOCKUP_DETECTOR_PERF or HAVE_HARDLOCKUP_DETECTOR_ARCH.
Alternatively an arch can define HAVE_NMI_WATCHDOG, which provides the
minimum arch_touch_nmi_watchdog, and it otherwise does its own thing and
does not implement the LOCKUP_DETECTOR interfaces.
sparc is unusual in that it has started to implement some of the
interfaces, but not fully yet. It should probably be converted to a full
HAVE_HARDLOCKUP_DETECTOR_ARCH.
[npiggin@gmail.com: fix]
Link: http://lkml.kernel.org/r/20170617223522.66c0ad88@roar.ozlabs.ibm.com
Link: http://lkml.kernel.org/r/20170616065715.18390-4-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For architectures that define HAVE_NMI_WATCHDOG, instead of having them
provide the complete touch_nmi_watchdog() function, just have them
provide arch_touch_nmi_watchdog().
This gives the generic code more flexibility in implementing this
function, and arch implementations don't miss out on touching the
softlockup watchdog or other generic details.
Link: http://lkml.kernel.org/r/20170616065715.18390-3-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add /proc/self/task/<current-tid>/fail-nth file that allows failing
0-th, 1-st, 2-nd and so on calls systematically.
Excerpt from the added documentation:
"Write to this file of integer N makes N-th call in the current task
fail (N is 0-based). Read from this file returns a single char 'Y' or
'N' that says if the fault setup with a previous write to this file
was injected or not, and disables the fault if it wasn't yet injected.
Note that this file enables all types of faults (slab, futex, etc).
This setting takes precedence over all other generic settings like
probability, interval, times, etc. But per-capability settings (e.g.
fail_futex/ignore-private) take precedence over it. This feature is
intended for systematic testing of faults in a single system call. See
an example below"
Why add a new setting:
1. Existing settings are global rather than per-task.
So parallel testing is not possible.
2. attr->interval is close but it depends on attr->count
which is non reset to 0, so interval does not work as expected.
3. Trying to model this with existing settings requires manipulations
of all of probability, interval, times, space, task-filter and
unexposed count and per-task make-it-fail files.
4. Existing settings are per-failure-type, and the set of failure
types is potentially expanding.
5. make-it-fail can't be changed by unprivileged user and aggressive
stress testing better be done from an unprivileged user.
Similarly, this would require opening the debugfs files to the
unprivileged user, as he would need to reopen at least times file
(not possible to pre-open before dropping privs).
The proposed interface solves all of the above (see the example).
We want to integrate this into syzkaller fuzzer. A prototype has found
10 bugs in kernel in first day of usage:
https://groups.google.com/forum/#!searchin/syzkaller/%22FAULT_INJECTION%22%7Csort:relevance
I've made the current interface work with all types of our sandboxes.
For setuid the secret sauce was prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) to
make /proc entries non-root owned. So I am fine with the current
version of the code.
[akpm@linux-foundation.org: fix build]
Link: http://lkml.kernel.org/r/20170328130128.101773-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With current epoll architecture target files are addressed with
file_struct and file descriptor number, where the last is not unique.
Moreover files can be transferred from another process via unix socket,
added into queue and closed then so we won't find this descriptor in the
task fdinfo list.
Thus to checkpoint and restore such processes CRIU needs to find out
where exactly the target file is present to add it into epoll queue.
For this sake one can use kcmp call where some particular target file
from the queue is compared with arbitrary file passed as an argument.
Because epoll target files can have same file descriptor number but
different file_struct a caller should explicitly specify the offset
within.
To test if some particular file is matching entry inside epoll one have
to
- fill kcmp_epoll_slot structure with epoll file descriptor,
target file number and target file offset (in case if only
one target is present then it should be 0)
- call kcmp as kcmp(pid1, pid2, KCMP_EPOLL_TFD, fd, &kcmp_epoll_slot)
- the kernel fetch file pointer matching file descriptor @fd of pid1
- lookups for file struct in epoll queue of pid2 and returns traditional
0,1,2 result for sorting purpose
Link: http://lkml.kernel.org/r/20170424154423.511592110@gmail.com
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrey Vagin <avagin@openvz.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Prevent use of uninitialized memory (originating from the stack frame of
do_sysctl()) by verifying that the name array is filled with sufficient
input data before comparing its specific entries with integer constants.
Through timing measurement or analyzing the kernel debug logs, a
user-mode program could potentially infer the results of comparisons
against the uninitialized memory, and acquire some (very limited)
information about the state of the kernel stack. The change also
eliminates possible future warnings by tools such as KMSAN and other
code checkers / instrumentations.
Link: http://lkml.kernel.org/r/20170524122139.21333-1-mjurczyk@google.com
Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Matthew Whitehead <tedheadster@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To keep parity with regular int interfaces provide the an unsigned int
proc_douintvec_minmax() which allows you to specify a range of allowed
valid numbers.
Adding proc_douintvec_minmax_sysadmin() is easy but we can wait for an
actual user for that.
Link: http://lkml.kernel.org/r/20170519033554.18592-6-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32
fields") added proc_douintvec() to start help adding support for
unsigned int, this however was only half the work needed. Two fixes
have come in since then for the following issues:
o Printing the values shows a negative value, this happens since
do_proc_dointvec() and this uses proc_put_long()
This was fixed by commit 5380e5644afbba9 ("sysctl: don't print negative
flag for proc_douintvec").
o We can easily wrap around the int values: UINT_MAX is 4294967295, if
we echo in 4294967295 + 1 we end up with 0, using 4294967295 + 2 we
end up with 1.
o We echo negative values in and they are accepted
This was fixed by commit 425fffd886ba ("sysctl: report EINVAL if value
is larger than UINT_MAX for proc_douintvec").
It still also failed to be added to sysctl_check_table()... instead of
adding it with the current implementation just provide a proper and
simplified unsigned int support without any array unsigned int support
with no negative support at all.
Historically sysctl proc helpers have supported arrays, due to the
complexity this adds though we've taken a step back to evaluate array
users to determine if its worth upkeeping for unsigned int. An
evaluation using Coccinelle has been done to perform a grammatical
search to ask ourselves:
o How many sysctl proc_dointvec() (int) users exist which likely
should be moved over to proc_douintvec() (unsigned int) ?
Answer: about 8
- Of these how many are array users ?
Answer: Probably only 1
o How many sysctl array users exist ?
Answer: about 12
This last question gives us an idea just how popular arrays: they are not.
Array support should probably just be kept for strings.
The identified uint ports are:
drivers/infiniband/core/ucma.c - max_backlog
drivers/infiniband/core/iwcm.c - default_backlog
net/core/sysctl_net_core.c - rps_sock_flow_sysctl()
net/netfilter/nf_conntrack_timestamp.c - nf_conntrack_timestamp -- bool
net/netfilter/nf_conntrack_acct.c nf_conntrack_acct -- bool
net/netfilter/nf_conntrack_ecache.c - nf_conntrack_events -- bool
net/netfilter/nf_conntrack_helper.c - nf_conntrack_helper -- bool
net/phonet/sysctl.c proc_local_port_range()
The only possible array users is proc_local_port_range() but it does not
seem worth it to add array support just for this given the range support
works just as well. Unsigned int support should be desirable more for
when you *need* more than INT_MAX or using int min/max support then does
not suffice for your ranges.
If you forget and by mistake happen to register an unsigned int proc
entry with an array, the driver will fail and you will get something as
follows:
sysctl table check failed: debug/test_sysctl//uint_0002 array now allowed
CPU: 2 PID: 1342 Comm: modprobe Tainted: G W E <etc>
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS <etc>
Call Trace:
dump_stack+0x63/0x81
__register_sysctl_table+0x350/0x650
? kmem_cache_alloc_trace+0x107/0x240
__register_sysctl_paths+0x1b3/0x1e0
? 0xffffffffc005f000
register_sysctl_table+0x1f/0x30
test_sysctl_init+0x10/0x1000 [test_sysctl]
do_one_initcall+0x52/0x1a0
? kmem_cache_alloc_trace+0x107/0x240
do_init_module+0x5f/0x200
load_module+0x1867/0x1bd0
? __symbol_put+0x60/0x60
SYSC_finit_module+0xdf/0x110
SyS_finit_module+0xe/0x10
entry_SYSCALL_64_fastpath+0x1e/0xad
RIP: 0033:0x7f042b22d119
<etc>
Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields")
Link: http://lkml.kernel.org/r/20170519033554.18592-5-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Suggested-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Liping Zhang <zlpnobody@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The mode sysctl_writes_strict positional checks keep being copy and pasted
as we add new proc handlers. Just add a helper to avoid code duplication.
Link: http://lkml.kernel.org/r/20170519033554.18592-4-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Suggested-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Document the different sysctl_writes_strict modes in code.
Link: http://lkml.kernel.org/r/20170519033554.18592-3-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently vmcoreinfo data is updated at boot time subsys_initcall(), it
has the risk of being modified by some wrong code during system is
running.
As a result, vmcore dumped may contain the wrong vmcoreinfo. Later on,
when using "crash", "makedumpfile", etc utility to parse this vmcore, we
probably will get "Segmentation fault" or other unexpected errors.
E.g. 1) wrong code overwrites vmcoreinfo_data; 2) further crashes the
system; 3) trigger kdump, then we obviously will fail to recognize the
crash context correctly due to the corrupted vmcoreinfo.
Now except for vmcoreinfo, all the crash data is well
protected(including the cpu note which is fully updated in the crash
path, thus its correctness is guaranteed). Given that vmcoreinfo data
is a large chunk prepared for kdump, we better protect it as well.
To solve this, we relocate and copy vmcoreinfo_data to the crash memory
when kdump is loading via kexec syscalls. Because the whole crash
memory will be protected by existing arch_kexec_protect_crashkres()
mechanism, we naturally protect vmcoreinfo_data from write(even read)
access under kernel direct mapping after kdump is loaded.
Since kdump is usually loaded at the very early stage after boot, we can
trust the correctness of the vmcoreinfo data copied.
On the other hand, we still need to operate the vmcoreinfo safe copy
when crash happens to generate vmcoreinfo_note again, we rely on vmap()
to map out a new kernel virtual address and update to use this new one
instead in the following crash_save_vmcoreinfo().
BTW, we do not touch vmcoreinfo_note, because it will be fully updated
using the protected vmcoreinfo_data after crash which is surely correct
just like the cpu crash note.
Link: http://lkml.kernel.org/r/1493281021-20737-3-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vmcoreinfo_max_size stands for the vmcoreinfo_data, the correct one we
should use is vmcoreinfo_note whose total size is VMCOREINFO_NOTE_SIZE.
Like explained in commit 77019967f06b ("kdump: fix exported size of
vmcoreinfo note"), it should not affect the actual function, but we
better fix it, also this change should be safe and backward compatible.
After this, we can get rid of variable vmcoreinfo_max_size, let's use
the corresponding macros directly, fewer variables means more safety for
vmcoreinfo operation.
[xlpang@redhat.com: fix build warning]
Link: http://lkml.kernel.org/r/1494830606-27736-1-git-send-email-xlpang@redhat.com
Link: http://lkml.kernel.org/r/1493281021-20737-2-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As Eric said,
"what we need to do is move the variable vmcoreinfo_note out of the
kernel's .bss section. And modify the code to regenerate and keep this
information in something like the control page.
Definitely something like this needs a page all to itself, and ideally
far away from any other kernel data structures. I clearly was not
watching closely the data someone decided to keep this silly thing in
the kernel's .bss section."
This patch allocates extra pages for these vmcoreinfo_XXX variables, one
advantage is that it enhances some safety of vmcoreinfo, because
vmcoreinfo now is kept far away from other kernel data structures.
Link: http://lkml.kernel.org/r/1493281021-20737-1-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Suggested-by: Eric Biederman <ebiederm@xmission.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The reason to disable interrupts seems to be to avoid switching to a
different processor while handling per cpu data using individual loads and
stores. If we use per cpu RMV primitives we will not have to disable
interrupts.
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1705171055130.5898@east.gentwo.org
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-and-tested-by: Meelis Roos <mroos@linux.ee>
Fixes: commit d9e968cb9f84 "getrlimit()/setrlimit(): move compat to native"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
My static checker complains that if "func" is NULL then "clear_filter"
is uninitialized. This seems like it could be true, although it's
possible something subtle is happening that I haven't seen.
kernel/trace/ftrace.c:3844 match_records()
error: uninitialized symbol 'clear_filter'.
Link: http://lkml.kernel.org/r/20170712073556.h6tkpjcdzjaozozs@mwanda
Cc: stable@vger.kernel.org
Fixes: f0a3b154bd7 ("ftrace: Clarify code for mod command")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
"func" can't be NULL and it doesn't make sense to check because we've
already derefenced it.
Link: http://lkml.kernel.org/r/20170712073340.4enzeojeoupuds5a@mwanda
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
With a shared policy in place, when one of the CPUs in the policy is
hotplugged out and then brought back online, sugov_stop() and
sugov_start() are called in order.
sugov_stop() removes utilization hooks for each CPU in the policy and
does nothing else in the for_each_cpu() loop. sugov_start() on the
other hand iterates through the CPUs in the policy and re-initializes
the per-cpu structure _and_ adds the utilization hook. This implies
that the scheduler is allowed to invoke a CPU's utilization update
hook when the rest of the per-cpu structures have yet to be
re-inited.
Apart from some strange values in tracepoints this doesn't cause a
problem, but if we do end up accessing a pointer from the per-cpu
sugov_cpu structure somewhere in the sugov_update_shared() path,
we will likely see crashes since the memset for another CPU in the
policy is free to race with sugov_update_shared from the CPU that is
ready to go. So let's fix this now to first init all per-cpu
structures, and then add the per-cpu utilization update hooks all at
once.
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Moving the irq_request/release_resources() callbacks out of the spinlocked,
irq disabled and bus locked region, unearthed an interesting abuse of the
irq_bus_lock/irq_bus_sync_unlock() callbacks.
The OMAP GPIO driver does merily power management inside of them. The
irq_request_resources() callback of this GPIO irqchip calls a function
which reads a GPIO register. That read aborts now because the clock of the
GPIO block is not magically enabled via the irq_bus_lock() callback.
Move the callbacks under the bus lock again to prevent this. In the
free_irq() path this requires to drop the bus_lock before calling
synchronize_irq() and reaquiring it before calling the
irq_release_resources() callback.
The bus lock can't be held because:
1) The data which has been changed between bus_lock/un_lock is cached in
the irq chip driver private data and needs to go out to the irq chip
via the slow bus (usually SPI or I2C) before calling
synchronize_irq().
That's the reason why this bus_lock/unlock magic exists in the first
place, as you cannot do SPI/I2C transactions while holding desc->lock
with interrupts disabled.
2) synchronize_irq() will actually deadlock, if there is a handler on
flight. These chips use threaded handlers for obvious reasons, as
they allow to do SPI/I2C communication. When the threaded handler
returns then bus_lock needs to be taken in irq_finalize_oneshot() as
we need to talk to the actual irq chip once more. After that the
threaded handler is marked done, which makes synchronize_irq() return.
So if we hold bus_lock accross the synchronize_irq() call, the
handler cannot mark itself done because it blocks on the bus
lock. That in turn makes synchronize_irq() wait forever on the
threaded handler to complete....
Add the missing unlock of desc->request_mutex in the error path of
__free_irq() and add a bunch of comments to explain the locking and
protection rules.
Fixes: 46e48e257360 ("genirq: Move irq resource handling out of spinlocked region")
Reported-and-tested-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Reported-and-tested-by: Tony Lindgren <tony@atomide.com>
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Not-longer-ranted-at-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
When modules are disabled, we get a harmless build warning:
kernel/trace/ftrace.c:4051:13: error: 'process_cached_mods' defined but not used [-Werror=unused-function]
This adds the same #ifdef around the new code that exists around
its caller.
Link: http://lkml.kernel.org/r/20170710084413.1820568-1-arnd@arndb.de
Fixes: d7fbf8df7ca0 ("ftrace: Implement cached modules tracing on module load")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The "stack_trace_filter" file only makes sense if DYNAMIC_FTRACE is
configured in. If it is not, then the user can not filter any functions.
Not only that, the open function causes warnings when DYNAMIC_FTRACE is not
set.
Link: http://lkml.kernel.org/r/20170710110521.600806-1-arnd@arndb.de
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The addition of TGID to the tracing header added a check to see if TGID
shoudl be displayed or not, and updated the header accordingly.
Unfortunately, it broke the default header.
Also add constant strings to use for spacing. This does remove the
visibility of the header a bit, but cuts it down from the extended lines
much greater than 80 characters.
Before this change:
# tracer: function
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU#|||| TIMESTAMP FUNCTION
# | | | |||| | |
swapper/0-1 [000] .... 0.277830: migration_init <-do_one_initcall
swapper/0-1 [002] d... 13.861967: Unknown type 1201
swapper/0-1 [002] d..1 13.861970: Unknown type 1202
After this change:
# tracer: function
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
swapper/0-1 [000] .... 0.278245: migration_init <-do_one_initcall
swapper/0-1 [003] d... 13.861189: Unknown type 1201
swapper/0-1 [003] d..1 13.861192: Unknown type 1202
Cc: Joel Fernandes <joelaf@google.com>
Fixes: 441dae8f2f29 ("tracing: Add support for display of tgid in trace output")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The move of the unpark functions to the control thread moved the BUG_ON()
there as well. While it made some sense in the idle thread of the upcoming
CPU, it's bogus to crash the control thread on the already online CPU,
especially as the function has a return value and the callsite is prepared
to handle an error return.
Replace it with a WARN_ON_ONCE() and return a proper error code.
Fixes: 9cd4f1a4e7a8 ("smp/hotplug: Move unparking of percpu threads to the control CPU")
Rightfully-ranted-at-by: Linux Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This reverts commit cc1582c231ea041fbc68861dfaf957eaf902b829.
This commit introduced a regression that broke rr-project, which uses sampling
events to receive a signal on overflow (but does not care about the contents
of the sample). These signals are critical to the correct operation of rr.
There's been some back and forth about how to fix it - but to not keep
applications in limbo queue up a revert.
Reported-by: Kyle Huey <me@kylehuey.com>
Acked-by: Kyle Huey <me@kylehuey.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170628105600.GC5981@leverpostej
Signed-off-by: Ingo Molnar <mingo@kernel.org>
