Christoph Hellwig noticed the following potential uninitialised use:
> arch/x86/kernel/tsc.c: In function 'time_cpufreq_notifier':
> arch/x86/kernel/tsc.c:634: warning: 'dummy' may be used uninitialized in this function
>
> where we do have CONFIG_SMP set, freq->flags & CPUFREQ_CONST_LOOPS is
> true and ref_freq is false.
It seems plausable, though the circumstances for hitting it are really low.
Nearly all SMP capable cpufreq drivers set CPUFREQ_CONST_LOOPS.
powernow-k8 is really the only exception. The older CPUs were typically
only ever UP. (powernow-k7 never supported SMP for eg)
It's worth fixing regardless, as it cleans up the code.
Fix possible uninitialized use of dummy, by just removing it,
and making the setting of lpj more obvious.
Signed-off-by: Dave Jones <davej@redhat.com>
I have been reading the documentation for cpufreq closely. Found a couple of
minor errors in the Documentation.
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Update the documentation accordingly.
Cleanup and use printk_once.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
This doesn't fix anything, but it's expected that a transition latency of 0
could cause trouble in the future.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Cc: Langsdorf, Mark <mark.langsdorf@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
With this patch you have following minimal sampling rate restrictions:
Kernel restrictions:
If CONFIG_NO_HZ is set, the limit is 10ms fixed.
If CONFIG_NO_HZ is not set or no_hz=off boot parameter is used, the
limits depend on the CONFIG_HZ option:
HZ=1000: min=20000us (20ms)
HZ=250: min=80000us (80ms)
HZ=100: min=200000us (200ms)
HW restrictions:
Do not sample/poll more often than HW latency * 100 exported by the low
level cpufreq HW driver
The higher value of above restrictions is the minimal sampling rate
that can be set (and can be seen via ondemand/sampling_rate_min sysfs file)
Default sampling rate still is HW latency * 1000, but this will now end
up in lower values on latest (Intel and AMD) hardware as these can switch
really fast and sampling rate mostly was limited to the 80ms or 200ms
(depending on whether HZ=250 or HZ=1000 is used).
Signed-off-by: Thomas Renninger <trenn@suse.de>
Cc: Pallipadi Venkatesh <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
This a very tight race where an interrupt could come in and not
have enough data to put into the end of a buffer page, and that
it would fail to write and need to go to the next page.
But if this happened when another writer was about to reserver
their data, and that writer has smaller data to reserve, then
it could succeed even though the interrupt moved the tail page.
To pervent that, if we fail to store data, and by subtracting the
amount we reserved we still have room for smaller data, we need
to fill that space with "discarded" data.
[ Impact: prevent race were buffer data may be lost ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
I forgot to update filter code accordingly in
"tracing/events: change the type of __str_loc_item to unsigned short"
(commt b0aae68cc5)
It can cause system crash:
# echo 1 > tracing/events/irq/irq_handler_entry/enable
# echo 'name == eth0' > tracing/events/irq/irq_handler_entry/filter
[ Impact: fix crash while filtering on __string() field ]
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A35B905.3090500@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
It's tracing_cpumask_new that should be kfree()ed.
This causes tracing_cpumask to be freed due to the typo:
# echo z > tracing_cpumask
bash: echo: write error: Invalid argument
And subsequent reads/writes to tracing_cpuamsk will access this
already-freed tracing_cpumask, thus may lead to crash.
[ Impact: fix leak and crash when writing invalid val to tracing_cpumask ]
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A35B86A.7070608@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
when compiling linux-mips with kmemtrace enabled, there will be an
error:
include/linux/trace_seq.h:12: error: 'PAGE_SIZE' undeclared here (not in
a function)
I checked the source code and found trace_seq.h used PAGE_SIZE but not
included the relative header file, so, fix it via adding the header file
<asm/page.h>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Wu Zhangjin <wuzj@lemote.com>
LKML-Reference: <1244962350-28702-1-git-send-email-wuzhangjin@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
I just realized this has a kmap_atomic bug in...
The below would fix it - but it's complicating this code
some more.
Alternatively I would have to introduce something like
pte_offset_map_irq() which would make the irq/nmi detection and leave
the regular code paths alone, however that would mean either duplicating
the gup_fast() pagewalk or passing down a pte function pointer, which
would only duplicate the gup_pte_range() bit, neither is really
attractive ...
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Nick Piggin <npiggin@suse.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch allows the Adaptec firmware to pass on its values for Packetize and
QAS. To do this, the settings max_iu and max_qas have been introduced into
the SPI transport class and populated from the adaptec NVram tables. Domain
validation in the SPI transport class will respect the max settings when
configuring to the highest possible speed for testing.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Contains the following changes:
- Fixed error paths retaking a spin lock which they already hold
- Added code to free memory in a couple of error paths
- Added code to free RPI bit map while unloading driver
- Added code to write zero to memory object allocated through dma_alloc_coherent
- Fixed crash/hang with target or LUN resets
Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Contains the following changes:
- Force vport to send LOGO to fabric controller when deleting vport
- Fixed driver failing to register login when a PLOGI is received
- Fixes for FIP discovery
- Added stricter checks for FCF addressing mode
- Added code to send only FLOGI, FDISC and LOGO to Fabric controller as FIP
- Fixed handling of LOGO from Fabric port
- Fixed consecutive link up events skipped link_down processing
Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Contains the following changes
- Set the CT field of FDISC to 3
- Fixed over allocation of SCSI buffers on SLI4
- Removed unused jump table entries
- Increase LPFC_WQE_DEF_COUNT to 256
- Updated FDISC context to VPI
- Fixed immediate SCSI command for LUN reset translation to WQE
- Extended mailbox handling to allow MBX_POLL commands in between async
MBQ commands
- Fixed SID used for FDISC
- Fix crash when accessing ctlregs from sysfs for SLI4 HBAs
- Fix SLI4 firmware version not being saved or displayed correctly
- Expand CQID field in WQE structure to 16 bits
- Fix post header template mailbox command timing out
- Removed FCoE PCI device ID 0x0705
Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reverted back a change in qla*_intr_handler code that caused an increase in
cpu cycles by allowing interrupts to occur while the instance hardware lock
was being held. Fix by taking the lock in irqsave mode.
Reported-and-tested-by: Douglas W. Styner <douglas.w.styner@intel.com>
Signed-off-by: Anirban Chakraborty <anirban.chakraborty@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Fix qla2xxx printk format warnings:
drivers/scsi/qla2xxx/qla_sup.c:915: warning: long long unsigned int format, u64 arg (arg 5)
drivers/scsi/qla2xxx/qla_sup.c:915: warning: long long unsigned int format, u64 arg (arg 6)
drivers/scsi/qla2xxx/qla_sup.c:923: warning: long long unsigned int format, u64 arg (arg 5)
drivers/scsi/qla2xxx/qla_sup.c:923: warning: long long unsigned int format, u64 arg (arg 6)
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Seokmann Ju <seokmann.ju@qlogic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Yong Wang reported the following compiler warning:
builtin-report.c: In function 'process_overflow_event':
builtin-report.c:984: error: cast to pointer from integer of different size
Which happens because we try to print ->ips[] out with a limited
format, losing the high 32 bits. Print it out using %016Lx instead.
Reported-by: Yong Wang <yong.y.wang@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
At present, every architecture that supports perf_counters has to
declare set_perf_counter_pending() in its arch-specific headers.
This consolidates the declarations into a single declaration in one
common place, include/linux/perf_counter.h. On powerpc, we continue
to provide a static inline definition of set_perf_counter_pending()
in the powerpc hw_irq.h.
Also, this removes from the x86 perf_counter.h the unused null
definitions of {test,clear}_perf_counter_pending.
Reported-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: benh@kernel.crashing.org
LKML-Reference: <18998.13388.920691.523227@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This fixes a couple of compile warnings that crept into the powerpc
perf_counter code recently:
CC arch/powerpc/kernel/perf_counter.o
arch/powerpc/kernel/perf_counter.c: In function 'record_and_restart':
arch/powerpc/kernel/perf_counter.c:1016: warning: unused variable 'addr'
arch/powerpc/kernel/perf_counter.c: In function 'hw_perf_counter_init':
arch/powerpc/kernel/perf_counter.c:891: warning: 'ev' may be used uninitialized in this function
Stephen Rothwell reported this against linux-next as well.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <18998.12884.787039.22202@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
These registers may contain values from previous kernels. So reset them
to known values before enable the event buffer again.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Take advantage of call-graph percounter sampling/recording to
display a non-trivial histogram: the true, collapsed/summarized
cost measurement, on a per system call total overhead basis:
aldebaran:~/linux/linux/tools/perf> ./perf record -g -a -f ~/hackbench 10
aldebaran:~/linux/linux/tools/perf> ./perf report -s symbol --syscalls | head -10
#
# (3536 samples)
#
# Overhead Symbol
# ........ ......
#
40.75% [k] sys_write
40.21% [k] sys_read
4.44% [k] do_nmi
...
This is done by accounting each (reliable) call-chain that chains back
to a given system call to that system call function.
[ So in the above example we can see that hackbench spends about 40% of
its total time somewhere in sys_write() and 40% somewhere in
sys_read(), the rest of the time is spent in user-space. The time
is not spent in sys_write() _itself_ but in one of its many child
functions. ]
Or, a recording of a (source files are already in the page-cache) kernel build:
$ perf record -g -m 512 -f -- make -j32 kernel
$ perf report -s s --syscalls | grep '\[k\]' | grep -v nmi
4.14% [k] do_page_fault
1.20% [k] sys_write
1.10% [k] sys_open
0.63% [k] sys_exit_group
0.48% [k] smp_apic_timer_interrupt
0.37% [k] sys_read
0.37% [k] sys_execve
0.20% [k] sys_mmap
0.18% [k] sys_close
0.14% [k] sys_munmap
0.13% [k] sys_poll
0.09% [k] sys_newstat
0.07% [k] sys_clone
0.06% [k] sys_newfstat
0.05% [k] sys_access
0.05% [k] schedule
Shows the true total cost of each syscall variant that gets used
during a kernel build. This profile reveals it that pagefaults are
the costliest, followed by read()/write().
An interesting detail: timer interrupts cost 0.5% - or 0.5 seconds
per 100 seconds of kernel build-time. (this was done with HZ=1000)
The summary is done in 'perf report', i.e. in the post-processing
stage - so once we have a good call-graph recording, this type of
non-trivial high-level analysis becomes possible.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
__copy_from_user_inatomic() isn't NMI safe in that it can trigger
the page fault handler which is another trap and its return path
invokes IRET which will also close the NMI context.
Therefore use a GUP based approach to copy the stack frames over.
We tried an alternative solution as well: we used a forward ported
version of Mathieu Desnoyers's "NMI safe INT3 and Page Fault" patch
that modifies the exception return path to use an open-coded IRET with
explicit stack unrolling and TF checking.
This didnt work as it interacted with faulting user-space instructions,
causing them not to restart properly, which corrupts user-space
registers.
Solving that would probably involve disassembling those instructions
and backtracing the RIP. But even without that, the code was deemed
rather complex to the already non-trivial x86 entry assembly code,
so instead we went for this GUP based method that does a
software-walk of the pagetables.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Simon triggered a lockdep inversion report about us taking ctx->mutex
vs counter->mutex in inverse orders. Fix that up.
Reported-by: Simon Holm Thøgersen <odie@cs.aau.dk>
Tested-by: Simon Holm Thøgersen <odie@cs.aau.dk>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The IOMMU spec states that IOMMU behavior may be undefined when the
IOMMU registers are rewritten while command or event buffer is enabled.
Disable them in IOMMU disable path.
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This false positive is due to field padding in struct sigqueue. When
this dynamically allocated structure is copied to the stack (in arch-
specific delivery code), kmemcheck sees a read from the padding, which
is, naturally, uninitialized.
Hide the false positive using the __GFP_NOTRACK_FALSE_POSITIVE flag.
Also made the rlimit override code a bit clearer by introducing a new
variable.
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
This false positive is due to the fact that do_mount_root() fakes a
mount option (which is normally read from userspace), and the kernel
unconditionally reads a whole page for the mount option.
Hide the false positive by using the new __getname_gfp() with the
__GFP_NOTRACK_FALSE_POSITIVE flag.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
The purpose of this change is to allow __getname() users to pass a
custom GFP mask to kmem_cache_alloc(). This is needed for annotating
a certain kmemcheck false positive.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
This gets rid of a heap of false-positive warnings from the tracer
code due to the use of bitfields.
[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
The use of bitfields here would lead to false positive warnings with
kmemcheck. Silence them.
(Additionally, one erroneous comment related to the bitfield was also
fixed.)
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
kmemcheck reports a use of uninitialized memory here, but it's not
a real error. The structure in question has just been allocated, and
the whole field is initialized, but it happens in two steps.
We fix the false positive by inserting a kmemcheck annotation.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Add the bitfield API which can be used to annotate bitfields in structs
and get rid of false positive reports.
According to Al Viro, the syntax we were using (putting #ifdef inside
macro arguments) was not valid C. He also suggested using begin/end
markers instead, which is what we do now.
[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
