xtensa: fix fast_syscall_spill_registers_fixup

fast_syscall_spill_registers_fixup was not correctly updated by the
'keep a3 and excsave1 on entry to exception handlers' patch: it doesn't
preserve a3 that it gets on entry, breaking _spill_registers in case of
page fault on stack during register spilling, leading to unhandled
exception in kernel mode.

Preserve a3 by saving it in the original _spill_registers stack frame's
a3 during exception handling and restoring it afterwards.

Also fix comments and function bounds annotations.

Reported-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Chris Zankel <chris@zankel.net>
xtensa: don't use alternate signal stack on threads

According to create_thread(3): "The new thread does not inherit the creating
thread's alternate signal stack". Since commit f9a3879a (Fix sigaltstack
corruption among cloned threads), current->sas_ss_size is set to 0 for cloned
processes sharing VM with their parent. Don't use the (nonexistent) alternate
signal stack in this case. This has been broken since commit 29c4dfd9 ([XTENSA]
Remove non-rt signal handling).

Fixes the SA_ONSTACK part of the nptl/tst-cancel20 test from uClibc.

Cc: <stable@vger.kernel.org>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
xtensa: Cocci spatch "noderef"

sizeof when applied to a pointer typed expression gives the size of the
pointer.
Found by coccinelle spatch "misc/noderef.cocci"

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Chris Zankel <chris@zankel.net>
perf script python: Fix mem leak due to missing Py_DECREFs on dict entries

We are using the Python scripting interface in perf to extract kernel
events relevant for performance analysis of HPC codes. We noticed that
the "perf script" call allocates a significant amount of memory (in the
order of several 100 MiB) during it's run, e.g. 125 MiB for a 25 MiB
input file:

  $> perf record -o perf.data -a -R -g fp \
       -e power:cpu_frequency -e sched:sched_switch \
       -e sched:sched_migrate_task -e sched:sched_process_exit \
       -e sched:sched_process_fork -e sched:sched_process_exec \
       -e cycles  -m 4096 --freq 4000
  $> /usr/bin/time perf script -i perf.data -s dummy_script.py
  0.84user 0.13system 0:01.92elapsed 51%CPU (0avgtext+0avgdata
  125532maxresident)k
  73072inputs+0outputs (57major+33086minor)pagefaults 0swaps

Upon further investigation using the valgrind massif tool, we noticed
that Python objects that are created in trace-event-python.c via
PyString_FromString*() (and their Integer and Long counterparts) are
never free'd.

The reason for this seem to be missing Py_DECREF calls on the objects
that are returned by these functions and stored in the Python
dictionaries. The Python dictionaries do not steal references (as
opposed to Python tuples and lists) but instead add their own reference.

Hence, the reference that is returned by these object creation functions
is never released and the memory is leaked. (see [1,2])

The attached patch fixes this by wrapping all relevant calls to
PyDict_SetItemString() and decrementing the reference counter
immediately after the Python function call.

This reduces the allocated memory to a reasonable amount:

  $> /usr/bin/time perf script -i perf.data -s dummy_script.py
  0.73user 0.05system 0:00.79elapsed 99%CPU (0avgtext+0avgdata
  49132maxresident)k
  0inputs+0outputs (0major+14045minor)pagefaults 0swaps

For comparison, with a 120 MiB input file the memory consumption
reported by time drops from almost 600 MiB to 146 MiB.

The patch has been tested using Linux 3.8.2 with Python 2.7.4 and Linux
3.11.6 with Python 2.7.5.

Please let me know if you need any further information.

[1] http://docs.python.org/2/c-api/tuple.html#PyTuple_SetItem
[2] http://docs.python.org/2/c-api/dict.html#PyDict_SetItemString

Signed-off-by: Joseph Schuchart <joseph.schuchart@tu-dresden.de>
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lkml.kernel.org/r/1381468543-25334-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
[SCSI] Revert "sg: push file descriptor list locking down to per-device locking"

This reverts commit 1f962ebcdfa15cede59e9edb299d1330949eec92.

This is one of four patches that was causing this bug

[  205.372823] ================================================
[  205.372901] [ BUG: lock held when returning to user space! ]
[  205.372979] 3.12.0-rc6-hw-debug-pagealloc+ #67 Not tainted
[  205.373055] ------------------------------------------------
[  205.373132] megarc.bin/5283 is leaving the kernel with locks still held!
[  205.373212] 1 lock held by megarc.bin/5283:
[  205.373285]  #0:  (&sdp->o_sem){.+.+..}, at: [<ffffffff8161e650>] sg_open+0x3a0/0x4d0

Cc: Vaughan Cao <vaughan.cao@oracle.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
[SCSI] Revert "sg: checking sdp->detached isn't protected when open"

This reverts commit e32c9e6300e3af659cbfe45e90a1e7dcd3572ada.

This is one of four patches that was causing this bug

[  205.372823] ================================================
[  205.372901] [ BUG: lock held when returning to user space! ]
[  205.372979] 3.12.0-rc6-hw-debug-pagealloc+ #67 Not tainted
[  205.373055] ------------------------------------------------
[  205.373132] megarc.bin/5283 is leaving the kernel with locks still held!
[  205.373212] 1 lock held by megarc.bin/5283:
[  205.373285]  #0:  (&sdp->o_sem){.+.+..}, at: [<ffffffff8161e650>] sg_open+0x3a0/0x4d0

Cc: Vaughan Cao <vaughan.cao@oracle.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
[SCSI] Revert "sg: no need sg_open_exclusive_lock"

This reverts commit 00b2d9d6d05b56fc1d77071ff8ccbd2c65b48dec.

This is one of four patches that was causing this bug

[  205.372823] ================================================
[  205.372901] [ BUG: lock held when returning to user space! ]
[  205.372979] 3.12.0-rc6-hw-debug-pagealloc+ #67 Not tainted
[  205.373055] ------------------------------------------------
[  205.373132] megarc.bin/5283 is leaving the kernel with locks still held!
[  205.373212] 1 lock held by megarc.bin/5283:
[  205.373285]  #0:  (&sdp->o_sem){.+.+..}, at: [<ffffffff8161e650>] sg_open+0x3a0/0x4d0

Cc: Vaughan Cao <vaughan.cao@oracle.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
[SCSI] Revert "sg: use rwsem to solve race during exclusive open"

This reverts commit 15b06f9a02406e5460001db6d5af5c738cd3d4e7.

This is one of four patches that was causing this bug

[  205.372823] ================================================
[  205.372901] [ BUG: lock held when returning to user space! ]
[  205.372979] 3.12.0-rc6-hw-debug-pagealloc+ #67 Not tainted
[  205.373055] ------------------------------------------------
[  205.373132] megarc.bin/5283 is leaving the kernel with locks still held!
[  205.373212] 1 lock held by megarc.bin/5283:
[  205.373285]  #0:  (&sdp->o_sem){.+.+..}, at: [<ffffffff8161e650>] sg_open+0x3a0/0x4d0

Cc: Vaughan Cao <vaughan.cao@oracle.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
perf tools: Fix up /proc/PID/maps parsing

When introducing support for MMAP2 we considered more parts of each map
representation in /proc/PID/maps, and when disabling it we forgot to
reduce the number of expected parsed/assigned entries in the sscanf
call, fix it to expect the right number of desired fields, 5.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Based-on-a-patch-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-vrbo1wik997ahjzl1chm3bdm@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

* Fix up /proc/PID/maps parsing, where perfectly fine mmap entries
  were being trown away when synthesizing PERF_RECORD_MMAP for
  preexisting threads, prevenging symbol resolution to work
  for those threads, broken in the MMAP2 removal. Reported and
  pinpointed by Markus Trippelsdorf,

* Fix mem leak in the python 'perf script' backend, due to missing Py_DECREFs
  on dict entries, fix from Joseph Schuchart.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf hists: Add color overhead for stdio output buffer

Following commit tightened up the buffer size for output to strict width
of used format columns:

  99cf666 perf hists: Fix formatting of long symbol names

This works fine until you hit color overhead output which places extra
bytes into output buffer. We need to account for color overhead in the
output buffer. Adding maximum color byte size to the output buffer size.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1382700293-1803-1-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf record: Split -g and --call-graph

Splitting -g and --call-graph for record command, so we could use '-g'
with no option.

The '-g' option now takes NO argument and enables the configured unwind
method, which is currently the frame pointers method.

It will be possible to configure unwind method via config file in
upcoming patches.

All current '-g' arguments is overtaken by --call-graph option.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: David Ahern <dsahern@gmail.com>
Tested-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: David Ahern <dsahern@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1382797536-32303-2-git-send-email-jolsa@redhat.com
[ reordered -g/--call-graph on --help and expanded the man page
  according to comments by David Ahern and Namhyung Kim ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf top: Split -G and --call-graph

Splitting -G and --call-graph for record command, so we could use '-G'
with no option.

The '-G' option now takes NO argument and enables the configured unwind
method, which is currently the frame pointers method.

It will be possible to configure unwind method via config file in
upcoming patches.

All current '-G' arguments is overtaken by --call-graph option.

NOTE: The documentation for top --call-graph option
      was wrongly copied from report command.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: David Ahern <dsahern@gmail.com>
Tested-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: David Ahern <dsahern@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1382797536-32303-3-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf tools: Fixup mmap event consumption

The tail position of the event buffer should only be modified after
actually use that event.

If not the event buffer could be invalid before use, and segment fault
occurs when invoking perf top -G.

Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Cc: David Ahern <dsahern@gmail.com>
Cc: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Link: http://lkml.kernel.org/r/1382600613-32177-1-git-send-email-zhouzhouyi@gmail.com
[ Simplified the logic using exit gotos and renamed write_tail method to mmap_consume ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
 "This is a set of four patches that revert functionality introduced in
  the merge window to sg.  The locking changes turned out to introduce
  this bug:

      [  205.372901] [ BUG: lock held when returning to user space! ]
   [...]
      [  205.373285]  #0:  (&sdp->o_sem){.+.+..}, at: [<ffffffff8161e650>] sg_open+0x3a0/0x4d0

  The fix is large, so at this late stage we'd like to revert the
  functionality and start again in the next merge window"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  [SCSI] Revert "sg: use rwsem to solve race during exclusive open"
  [SCSI] Revert "sg: no need sg_open_exclusive_lock"
  [SCSI] Revert "sg: checking sdp->detached isn't protected when open"
  [SCSI] Revert "sg: push file descriptor list locking down to per-device locking"
Merge tag 'xtensa-next-20131015' of git://github.com/czankel/xtensa-linux

Pull Xtensa patchset from Chris Zankel:
 "The main patch fixes a bug that can cause a kernel panic, and was
  introduced in rc1.  The other two have been discovered by a uclibc
  test and 'coccinelle'"

* tag 'xtensa-next-20131015' of git://github.com/czankel/xtensa-linux:
  xtensa: Cocci spatch "noderef"
  xtensa: don't use alternate signal stack on threads
  xtensa: fix fast_syscall_spill_registers_fixup
Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

 * Add color overhead for stdio output buffer, which fixes
   --stdio output being chopped up on the hot (red) entries,
   fix from Jiri Olsa.

 * Get 'perf record -g -a sleep 1' working again, removing the
   need for -- separating perf options from the workload, restoring
   ages old behaviour, fix from Jiri Olsa.
   More patches allowing ~/.perfconfig setting up of default
   callchain collecting method ("fp" or "dwarf") left for next
   merge window.

 * Fixup mmap event consumption, where we were acking the
   consumption by writing the tail before actually accessing
   the event, which could lead to using overwritten records
   in things like 'perf record --call-graph'. From Zhouyi Zhou.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Kconfig: make KOBJECT_RELEASE debugging require timer debugging

Without the timer debugging, the delayed kobject release will just
result in undebuggable oopses if it triggers any latent bugs.  That
doesn't actually help debugging at all.

So make DEBUG_KOBJECT_RELEASE depend on DEBUG_OBJECTS_TIMERS to avoid
having people enable one without the other.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf tooling fixes from Ingo Molnar:
 "This contains five tooling fixes:

   - fix a remaining mmap2 assumption which resulted in perf top output
     breakage
   - fix mmap ring-buffer processing bug that corrupts data
   - fix for a severe python scripting memory leak
   - fix broken (and user-visible) -g option handling
   - fix stdio output

  The diffstat size is larger than what we'd like to see this late :-/"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Fixup mmap event consumption
  perf top: Split -G and --call-graph
  perf record: Split -g and --call-graph
  perf hists: Add color overhead for stdio output buffer
  perf tools: Fix up /proc/PID/maps parsing
  perf script python: Fix mem leak due to missing Py_DECREFs on dict entries
Fix a few incorrectly checked [io_]remap_pfn_range() calls

Nico Golde reports a few straggling uses of [io_]remap_pfn_range() that
really should use the vm_iomap_memory() helper.  This trivially converts
two of them to the helper, and comments about why the third one really
needs to continue to use remap_pfn_range(), and adds the missing size
check.

Reported-by: Nico Golde <nico@ngolde.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org.