Pull power tools fixes from Len Brown:
"A pair of power tools patches -- a 3.7 regression fix plus a bug fix."
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
tools/power turbostat: graceful fail on garbage input
tools/power turbostat: Repair Segmentation fault when using -i option
Revert commit 03a7beb55b ("epoll: support for disabling items, and a
self-test app") pending resolution of the issues identified by Michael
Kerrisk, copied below.
We'll revisit this for 3.8.
: I've taken a look at this patch as it currently stands in 3.7-rc1, and
: done a bit of testing. (By the way, the test program
: tools/testing/selftests/epoll/test_epoll.c does not compile...)
:
: There are one or two places where the behavior seems a little strange,
: so I have a question or two at the end of this mail. But other than
: that, I want to check my understanding so that the interface can be
: correctly documented.
:
: Just to go though my understanding, the problem is the following
: scenario in a multithreaded application:
:
: 1. Multiple threads are performing epoll_wait() operations,
: and maintaining a user-space cache that contains information
: corresponding to each file descriptor being monitored by
: epoll_wait().
:
: 2. At some point, a thread wants to delete (EPOLL_CTL_DEL)
: a file descriptor from the epoll interest list, and
: delete the corresponding record from the user-space cache.
:
: 3. The problem with (2) is that some other thread may have
: previously done an epoll_wait() that retrieved information
: about the fd in question, and may be in the middle of using
: information in the cache that relates to that fd. Thus,
: there is a potential race.
:
: 4. The race can't solved purely in user space, because doing
: so would require applying a mutex across the epoll_wait()
: call, which would of course blow thread concurrency.
:
: Right?
:
: Your solution is the EPOLL_CTL_DISABLE operation. I want to
: confirm my understanding about how to use this flag, since
: the description that has accompanied the patches so far
: has been a bit sparse
:
: 0. In the scenario you're concerned about, deleting a file
: descriptor means (safely) doing the following:
: (a) Deleting the file descriptor from the epoll interest list
: using EPOLL_CTL_DEL
: (b) Deleting the corresponding record in the user-space cache
:
: 1. It's only meaningful to use this EPOLL_CTL_DISABLE in
: conjunction with EPOLLONESHOT.
:
: 2. Using EPOLL_CTL_DISABLE without using EPOLLONESHOT in
: conjunction is a logical error.
:
: 3. The correct way to code multithreaded applications using
: EPOLL_CTL_DISABLE and EPOLLONESHOT is as follows:
:
: a. All EPOLL_CTL_ADD and EPOLL_CTL_MOD operations should
: should EPOLLONESHOT.
:
: b. When a thread wants to delete a file descriptor, it
: should do the following:
:
: [1] Call epoll_ctl(EPOLL_CTL_DISABLE)
: [2] If the return status from epoll_ctl(EPOLL_CTL_DISABLE)
: was zero, then the file descriptor can be safely
: deleted by the thread that made this call.
: [3] If the epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY,
: then the descriptor is in use. In this case, the calling
: thread should set a flag in the user-space cache to
: indicate that the thread that is using the descriptor
: should perform the deletion operation.
:
: Is all of the above correct?
:
: The implementation depends on checking on whether
: (events & ~EP_PRIVATE_BITS) == 0
: This replies on the fact that EPOLL_CTL_AD and EPOLL_CTL_MOD always
: set EPOLLHUP and EPOLLERR in the 'events' mask, and EPOLLONESHOT
: causes those flags (as well as all others in ~EP_PRIVATE_BITS) to be
: cleared.
:
: A corollary to the previous paragraph is that using EPOLL_CTL_DISABLE
: is only useful in conjunction with EPOLLONESHOT. However, as things
: stand, one can use EPOLL_CTL_DISABLE on a file descriptor that does
: not have EPOLLONESHOT set in 'events' This results in the following
: (slightly surprising) behavior:
:
: (a) The first call to epoll_ctl(EPOLL_CTL_DISABLE) returns 0
: (the indicator that the file descriptor can be safely deleted).
: (b) The next call to epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY.
:
: This doesn't seem particularly useful, and in fact is probably an
: indication that the user made a logic error: they should only be using
: epoll_ctl(EPOLL_CTL_DISABLE) on a file descriptor for which
: EPOLLONESHOT was set in 'events'. If that is correct, then would it
: not make sense to return an error to user space for this case?
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Paton J. Lewis" <palewis@adobe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull ktest confusion fix from Steven Rostedt:
"With the v3.7-rc2 kernel, the network cards on my target boxes were
not being brought up.
I found that the modules for the network was not being installed.
This was due to the config CONFIG_MODULES_USE_ELF_RELA that came
before CONFIG_MODULES, and confused ktest in thinking that
CONFIG_MODULES=y was not found.
Ktest needs to test all configs and not just stop if something starts
with CONFIG_MODULES."
* tag 'ktest-v3.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-ktest:
ktest: Fix ktest confusion with CONFIG_MODULES_USE_ELF_RELA
Pull perf fixes from Ingo Molnar:
"Most of the kernel diffstat relates to a group of Intel P6 and KNC
(Xeon-Phi Knights Corner) PMU driver fixes, neither of which is in
heavy use, so we took the fixes.
The rest is diverse smallish fixes to the tooling and kernel side."
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86: Remove unused variable in nhmex_rbox_alter_er()
perf/x86: Enable overflow on Intel KNC with a custom knc_pmu_handle_irq()
perf/x86: Remove cpuc->enable check on Intl KNC event enable/disable
perf/x86: Make Intel KNC use full 40-bit width of counters
perf/x86/uncore: Handle pci_read_config_dword() errors
perf/x86: Remove P6 cpuc->enabled check
perf/x86: Update/fix generic events on P6 PMU
perf/x86: Fix P6 FP_ASSIST event constraint
perf, cpu hotplug: Use cached value of smp_processor_id()
perf, cpu hotplug: Run CPU_STARTING notifiers with irqs disabled
x86/perf: Fix virtualization sanity check
perf test: Fix exclude_guest parse events tests
perf tools: do not flush maps on COMM for perf report
perf help: Fix --help for builtins
perf trace: Check if sample raw_data field is set
perf trace: Validate syscall id before growing syscall table
In order to decide if ktest should bother installing modules on the
target box, it checks if the config file has CONFIG_MODULES=y. But it
also checks if the '=y' part exists. It only will install modules if the
config exists and is set with '=y'. But as the regex that was used
tests:
/^CONFIG_MODULES(=y)?/
this will also match:
CONFIG_MODULES_USE_ELF_RELA
as the '=y' part was optional and it did not test the rest of the line.
When this happens, ktest will stop checking the rest of the configs but
it will also think that no modules are needed to be installed. What it
should do is only jump out of the loop if it actually found a
CONFIG_MODULES that is set to true.
Otherwise, ktest wont install the necessary modules needed for proper
booting of the test target.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Latest Linus head run of "make selftests" in the tools directory failed
with references to undefined variables. Reference was to
'write_thread_data' which is the name of a struct that is being used, not
the variable itself. Change reference so it points to the variable.
Signed-off-by: Daniel Hazelton <dshadowwolf@gmail.com>
Cc: "Paton J. Lewis" <palewis@adobe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix tools/vm/page-types.c to use the UAPI variant of linux/kernel-page-flags.h
lest the following error appear:
In file included from page-types.c:38:0:
../../include/linux/kernel-page-flags.h:4:42: fatal error:
uapi/linux/kernel-page-flags.h: No such file or directory
Reported-by: Daniel Hazelton <dshadowwolf@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Fengguang Wu <fengguang.wu@intel.com>
Tested-by: Daniel Hazelton <dshadowwolf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Event parsing tests are broken by following commit:
perf tool: Precise mode requires exclude_guest
commit 1342798cc1
Author: David Ahern <dsahern@gmail.com>
Date: Thu Sep 13 14:59:13 2012 -0600
which enables 'exclude_guest' modifier any time the 'precise'
modifier is detected.
Fixing related tests and adding special comment.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: David Ahern <dsahern@gmail.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Namhyung Kim reported that the build fails with:
GEN python/perf.so
gcc: error: python_ext_build/tmp//../../libtraceevent.a: No such file or directory
error: command 'gcc' failed with exit status 1
cp: cannot stat `python_ext_build/lib/perf.so': No such file or directory
make: *** [python/perf.so] Error 1
We need to propagate the TE_PATH variable to the setup.py file.
Reported-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/n/tip-8umiPbm4sxpknKivbjgykhut@git.kernel.org
[ Fixed superfluous variable build error. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
* The python binding needs to link with libtraceevent and to initialize
the 'page_size' variable so that mmaping works again.
* The callchain folding character that appears on the TUI just before
the overhead had disappeared due to recent changes, add it back.
* Intel PEBS in VT-x context uses the DS address as a guest linear address,
even though its programmed by the host as a host linear address. This either
results in guest memory corruption and or the hardware faulting and 'crashing'
the virtual machine. Therefore we have to disable PEBS on VT-x enter and
re-enable on VT-x exit, enforcing a strict exclude_guest.
Kernel side enforcement fix by Peter Zijlstra, tooling side fix by David Ahern.
* Fix build on sparc due to UAPI, fix from David Miller.
* Fixes for the srclike sort key for unresolved symbols and when processing
samples in JITted code, where we don't have an ELF file, just an special
symbol table, fixes from Namhyung Kim.
* Fix some leaks in libtraceevent, from Steven Rostedt.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Even though with the change of commit commit 2b29175 "tools lib
traceevent: Carve out events format parsing routine", allowed
__pevent_parse_format() to parse an event without the need of a pevent
handler, the event still needs to assign the pevent handed to it.
There's no problem with assigning it if the pevent is NULL, as the
event->pevent would be NULL without the assignment. But function parsing
handlers may be assigned to the pevent handler to help in parsing the
event. If there's no pevent then there would not be any function
handlers, but if the pevent isn't assigned first before parsing the
event, it wont honor the function handlers that were assigned.
Worse yet, the current code crashes if an event has a function that it
tries to parse. For example:
# perf record -e scsi:scsi_dispatch_cmd_timeout
Segmentation fault (core dumped)
This happens because the scsi_dispatch_cmd_timeout event format has the following:
scsi_trace_parse_cdb(p, __get_dynamic_array(cmnd), REC->cmd_len)
which hasn't been defined by the pevent code.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1349136831.22822.133.camel@gandalf.local.home
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
