In memremap's helper function try_ram_remap(), we dereference a struct
page pointer that was derived from a PFN that is known to be covered by
a 'System RAM' iomem region, and is thus assumed to be a 'valid' PFN,
i.e., a PFN that has a struct page associated with it and is covered by
the kernel direct mapping.
However, the assumption that there is a 1:1 relation between the System
RAM iomem region and the kernel direct mapping is not universally valid
on all architectures, and on ARM and arm64, 'System RAM' may include
regions for which pfn_valid() returns false.
Generally speaking, both __va() and pfn_to_page() should only ever be
called on PFNs/physical addresses for which pfn_valid() returns true, so
add that check to try_ram_remap().
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Functions which the compiler has instrumented for KASAN place poison on
the stack shadow upon entry and remove this poision prior to returning.
In the case of CPU hotplug, CPUs exit the kernel a number of levels deep
in C code. Any instrumented functions on this critical path will leave
portions of the stack shadow poisoned.
When a CPU is subsequently brought back into the kernel via a different
path, depending on stackframe, layout calls to instrumented functions
may hit this stale poison, resulting in (spurious) KASAN splats to the
console.
To avoid this, clear any stale poison from the idle thread for a CPU
prior to bringing a CPU online.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The check for whether we overlap "System RAM" needs to be done at
section granularity. For example a system with the following mapping:
100000000-37bffffff : System RAM
37c000000-837ffffff : Persistent Memory
...is unable to use devm_memremap_pages() as it would result in two
zones colliding within a given section.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Given we have uninitialized list_heads being passed to list_add() it
will always be the case that those uninitialized values randomly trigger
the poison value. Especially since a list_add() operation will seed the
stack with the poison value for later stack allocations to trip over.
For example, see these two false positive reports:
list_add attempted on force-poisoned entry
WARNING: at lib/list_debug.c:34
[..]
NIP [c00000000043c390] __list_add+0xb0/0x150
LR [c00000000043c38c] __list_add+0xac/0x150
Call Trace:
__list_add+0xac/0x150 (unreliable)
__down+0x4c/0xf8
down+0x68/0x70
xfs_buf_lock+0x4c/0x150 [xfs]
list_add attempted on force-poisoned entry(0000000000000500),
new->next == d0000000059ecdb0, new->prev == 0000000000000500
WARNING: at lib/list_debug.c:33
[..]
NIP [c00000000042db78] __list_add+0xa8/0x140
LR [c00000000042db74] __list_add+0xa4/0x140
Call Trace:
__list_add+0xa4/0x140 (unreliable)
rwsem_down_read_failed+0x6c/0x1a0
down_read+0x58/0x60
xfs_log_commit_cil+0x7c/0x600 [xfs]
Fixes: commit 5c2c2587b1 ("mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Eryu Guan <eguan@redhat.com>
Tested-by: Eryu Guan <eguan@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull tracing fix from Steven Rostedt:
"A feature was added in 4.3 that allowed users to filter trace points
on a tasks "comm" field. But this prevented filtering on a comm field
that is within a trace event (like sched_migrate_task).
When trying to filter on when a program migrated, this change
prevented the filtering of the sched_migrate_task.
To fix this, the event fields are examined first, and then the extra
fields like "comm" and "cpu" are examined. Also, instead of testing
to assign the comm filter function based on the field's name, the
generic comm field is given a new filter type (FILTER_COMM). When
this field is used to filter the type is checked. The same is done
for the cpu filter field.
Two new special filter types are added: "COMM" and "CPU". This allows
users to still filter the tasks comm for events that have "comm" as
one of their fields, in cases that users would like to filter
sched_migrate_task on the comm of the task that called the event, and
not the comm of the task that is being migrated"
* tag 'trace-fixes-v4.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Do not have 'comm' filter override event 'comm' field
Commit 9f61668073 "tracing: Allow triggers to filter for CPU ids and
process names" added a 'comm' filter that will filter events based on the
current tasks struct 'comm'. But this now hides the ability to filter events
that have a 'comm' field too. For example, sched_migrate_task trace event.
That has a 'comm' field of the task to be migrated.
echo 'comm == "bash"' > events/sched_migrate_task/filter
will now filter all sched_migrate_task events for tasks named "bash" that
migrates other tasks (in interrupt context), instead of seeing when "bash"
itself gets migrated.
This fix requires a couple of changes.
1) Change the look up order for filter predicates to look at the events
fields before looking at the generic filters.
2) Instead of basing the filter function off of the "comm" name, have the
generic "comm" filter have its own filter_type (FILTER_COMM). Test
against the type instead of the name to assign the filter function.
3) Add a new "COMM" filter that works just like "comm" but will filter based
on the current task, even if the trace event contains a "comm" field.
Do the same for "cpu" field, adding a FILTER_CPU and a filter "CPU".
Cc: stable@vger.kernel.org # v4.3+
Fixes: 9f61668073 "tracing: Allow triggers to filter for CPU ids and process names"
Reported-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull perf fixes from Thomas Gleixner:
"A rather largish series of 12 patches addressing a maze of race
conditions in the perf core code from Peter Zijlstra"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Robustify task_function_call()
perf: Fix scaling vs. perf_install_in_context()
perf: Fix scaling vs. perf_event_enable()
perf: Fix scaling vs. perf_event_enable_on_exec()
perf: Fix ctx time tracking by introducing EVENT_TIME
perf: Cure event->pending_disable race
perf: Fix race between event install and jump_labels
perf: Fix cloning
perf: Only update context time when active
perf: Allow perf_release() with !event->ctx
perf: Do not double free
perf: Close install vs. exit race
Pull scheduler fixlet from Thomas Gleixner:
"A trivial printk typo fix"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Fix trivial typo in printk() message
Pull tracing fix from Steven Rostedt:
"Another small bug reported to me by Chunyu Hu.
When perf added a "reg" function to the function tracing event (not a
tracepoint), it caused that event to be displayed as a tracepoint and
could cause errors in tracepoint handling. That was solved by adding
a flag to ignore ftrace non-tracepoint events. But that flag was
missed when displaying events in available_events, which should only
contain tracepoint events.
This broke a documented way to enable all events with:
cat available_events > set_event
As the function non-tracepoint event would cause that to error out.
The commit here fixes that by having the available_events file not
list events that have the ignore flag set"
* tag 'trace-fixes-v4.5-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix showing function event in available_events
Pull libnvdimm fixes from Dan Williams:
- Two fixes for compatibility with the ACPI 6.1 specification.
Without these fixes multi-interface DIMMs will fail to be probed, and
address range scrub commands to find memory errors will give results
that the kernel will mis-interpret. For multi-interface DIMMs Linux
will accept either the original 6.0 implementation or 6.1.
For address range scrub we'll only support 6.1 since ACPI formalized
this DSM differently than the original example [1] implemented in
v4.2. The expectation is that production systems will only ever ship
the ACPI 6.1 address range scrub command definition.
- The wider async address range scrub work targeting 4.6 discovered
that the original synchronous implementation in 4.5 is not sizing its
return buffer correctly.
- Arnd caught that my recent fix to the size of the pfn_t flags missed
updating the flags variable used in the pmem driver.
- Toshi found that we mishandle the memremap() return value in
devm_memremap().
* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
nvdimm: use 'u64' for pfn flags
devm_memremap: Fix error value when memremap failed
nfit: update address range scrub commands to the acpi 6.1 format
libnvdimm, tools/testing/nvdimm: fix 'ars_status' output buffer sizing
nfit: fix multi-interface dimm handling, acpi6.1 compatibility
Currently any ctx_sched_in() call will re-start the ctx time tracking,
this means that calls like:
ctx_sched_in(.event_type = EVENT_PINNED);
ctx_sched_in(.event_type = EVENT_FLEXIBLE);
will have a hole in their ctx time tracking. This is likely harmless
but can confuse things a little. By adding EVENT_TIME, we can have the
first ctx_sched_in() (is_active: 0 -> !0) start the time and any
further ctx_sched_in() will leave the timestamps alone.
Secondly, this allows for an early disable like:
ctx_sched_out(.event_type = EVENT_TIME);
which would update the ctx time (if the ctx is active) and any further
calls to ctx_sched_out() would not further modify the ctx time.
For ctx_sched_in() any 0 -> !0 transition will automatically include
EVENT_TIME.
For ctx_sched_out(), any transition that clears EVENT_ALL will
automatically clear EVENT_TIME.
These two rules ensure that under normal circumstances we need not
bother with EVENT_TIME and get natural ctx time behaviour.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: 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: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: eranian@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160224174948.100446561@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf_install_in_context() relies upon the context switch hooks to have
scheduled in events when the IPI misses its target -- after all, if
the task has moved from the CPU (or wasn't running at all), it will
have to context switch to run elsewhere.
This however doesn't appear to be happening.
It is possible for the IPI to not happen (task wasn't running) only to
later observe the task running with an inactive context.
The only possible explanation is that the context switch hooks are not
called. Therefore put in a sync_sched() after toggling the jump_label
to guarantee all CPUs will have them enabled before we install an
event.
A simple if (0->1) sync_sched() will not in fact work, because any
further increment can race and complete before the sync_sched().
Therefore we must jump through some hoops.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: 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: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: eranian@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160224174947.980211985@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Alexander reported that when the 'original' context gets destroyed, no
new clones happen.
This can happen irrespective of the ctx switch optimization, any task
can die, even the parent, and we want to continue monitoring the task
hierarchy until we either close the event or no tasks are left in the
hierarchy.
perf_event_init_context() will attempt to pin the 'parent' context
during clone(). At that point current is the parent, and since current
cannot have exited while executing clone(), its context cannot have
passed through perf_event_exit_task_context(). Therefore
perf_pin_task_context() cannot observe ctx->task == TASK_TOMBSTONE.
However, since inherit_event() does:
if (parent_event->parent)
parent_event = parent_event->parent;
it looks at the 'original' event when it does: is_orphaned_event().
This can return true if the context that contains the this event has
passed through perf_event_exit_task_context(). And thus we'll fail to
clone the perf context.
Fix this by adding a new state: STATE_DEAD, which is set by
perf_release() to indicate that the filedesc (or kernel reference) is
dead and there are no observers for our data left.
Only for STATE_DEAD will is_orphaned_event() be true and inhibit
cloning.
STATE_EXIT is otherwise preserved such that is_event_hup() remains
functional and will report when the observed task hierarchy becomes
empty.
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-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: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: eranian@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Fixes: c6e5b73242 ("perf: Synchronously clean up child events")
Link: http://lkml.kernel.org/r/20160224174947.919845295@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The ftrace:function event is only displayed for parsing the function tracer
data. It is not used to enable function tracing, and does not include an
"enable" file in its event directory.
Originally, this event was kept separate from other events because it did
not have a ->reg parameter. But perf added a "reg" parameter for its use
which caused issues, because it made the event available to functions where
it was not compatible for.
Commit 9b63776fa3 "tracing: Do not enable function event with enable"
added a TRACE_EVENT_FL_IGNORE_ENABLE flag that prevented the function event
from being enabled by normal trace events. But this commit missed keeping
the function event from being displayed by the "available_events" directory,
which is used to show what events can be enabled by set_event.
One documented way to enable all events is to:
cat available_events > set_event
But because the function event is displayed in the available_events, this
now causes an INVALID error:
cat: write error: Invalid argument
Reported-by: Chunyu Hu <chuhu@redhat.com>
Fixes: 9b63776fa3 "tracing: Do not enable function event with enable"
Cc: stable@vger.kernel.org # 3.4+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
devm_memremap() returns an ERR_PTR() value in case of error.
However, it returns NULL when memremap() failed. This causes
the caller, such as the pmem driver, to proceed and oops later.
Change devm_memremap() to return ERR_PTR(-ENXIO) when memremap()
failed.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Pull tracing fixes from Steven Rostedt:
"Two more small fixes.
One is by Yang Shi who added a READ_ONCE_NOCHECK() to the scan of the
stack made by the stack tracer. As the stack tracer scans the entire
kernel stack, KASAN triggers seeing it as a "stack out of bounds"
error. As the scan is looking at the contents of the stack from
parent functions. The NOCHECK() tells KASAN that this is done on
purpose, and is not some kind of stack overflow.
The second fix is to the ftrace selftests, to retrieve the PID of
executed commands from the shell with '$!' and not by parsing 'jobs'"
* tag 'trace-fixes-v4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing, kasan: Silence Kasan warning in check_stack of stack_tracer
ftracetest: Fix instance test to use proper shell command for pids
Ard Biesheuvel
Mark Rutland
Dan Williams
Linus Torvalds
Steven Rostedt (Red Hat)
Peter Zijlstra
Toshi Kani