27 Jan, 2010
1 commit
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Lockdep has found the real bug, but the output doesn't look right to me:
> =========================================================
> [ INFO: possible irq lock inversion dependency detected ]
> 2.6.33-rc5 #77
> ---------------------------------------------------------
> emacs/1609 just changed the state of lock:
> (&(&tty->ctrl_lock)->rlock){+.....}, at: [] tty_fasync+0xe8/0x190
> but this lock took another, HARDIRQ-unsafe lock in the past:
> (&(&sighand->siglock)->rlock){-.....}"HARDIRQ-unsafe" and "this lock took another" looks wrong, afaics.
> ... key at: [] __key.46539+0x0/0x8
> ... acquired at:
> [] __lock_acquire+0x1056/0x15a0
> [] lock_acquire+0x9f/0x120
> [] _raw_spin_lock_irqsave+0x52/0x90
> [] __proc_set_tty+0x3e/0x150
> [] tty_open+0x51d/0x5e0The stack-trace shows that this lock (ctrl_lock) was taken under
->siglock (which is hopefully irq-safe).This is a clear typo in check_usage_backwards() where we tell the print a
fancy routine we're forwards.Signed-off-by: Oleg Nesterov
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
15 Dec, 2009
4 commits
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Name space cleanup. No functional change.
Signed-off-by: Thomas Gleixner
Acked-by: Peter Zijlstra
Acked-by: David S. Miller
Acked-by: Ingo Molnar
Cc: linux-arch@vger.kernel.org -
Further name space cleanup. No functional change
Signed-off-by: Thomas Gleixner
Acked-by: Peter Zijlstra
Acked-by: David S. Miller
Acked-by: Ingo Molnar
Cc: linux-arch@vger.kernel.org -
The raw_spin* namespace was taken by lockdep for the architecture
specific implementations. raw_spin_* would be the ideal name space for
the spinlocks which are not converted to sleeping locks in preempt-rt.Linus suggested to convert the raw_ to arch_ locks and cleanup the
name space instead of using an artifical name like core_spin,
atomic_spin or whateverNo functional change.
Signed-off-by: Thomas Gleixner
Acked-by: Peter Zijlstra
Acked-by: David S. Miller
Acked-by: Ingo Molnar
Cc: linux-arch@vger.kernel.org -
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits)
m68k: rename global variable vmalloc_end to m68k_vmalloc_end
percpu: add missing per_cpu_ptr_to_phys() definition for UP
percpu: Fix kdump failure if booted with percpu_alloc=page
percpu: make misc percpu symbols unique
percpu: make percpu symbols in ia64 unique
percpu: make percpu symbols in powerpc unique
percpu: make percpu symbols in x86 unique
percpu: make percpu symbols in xen unique
percpu: make percpu symbols in cpufreq unique
percpu: make percpu symbols in oprofile unique
percpu: make percpu symbols in tracer unique
percpu: make percpu symbols under kernel/ and mm/ unique
percpu: remove some sparse warnings
percpu: make alloc_percpu() handle array types
vmalloc: fix use of non-existent percpu variable in put_cpu_var()
this_cpu: Use this_cpu_xx in trace_functions_graph.c
this_cpu: Use this_cpu_xx for ftrace
this_cpu: Use this_cpu_xx in nmi handling
this_cpu: Use this_cpu operations in RCU
this_cpu: Use this_cpu ops for VM statistics
...Fix up trivial (famous last words) global per-cpu naming conflicts in
arch/x86/kvm/svm.c
mm/slab.c
10 Dec, 2009
1 commit
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ia64 found this the hard way (because we currently have a stub
for save_stack_trace() that does nothing). But it would be a
good idea to be cautious in case a real save_stack_trace()
bailed out with an error before it set trace->nr_entries.Signed-off-by: Tony Luck
Acked-by: Peter Zijlstra
Cc: luming.yu@intel.com
LKML-Reference:
Signed-off-by: Ingo Molnar
06 Dec, 2009
1 commit
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Fix min, max times in /proc/lock_stats
(1) When collecting lock hold and wait times, if the current minimum
time is zero, it will be replaced by the next time.(2) When aggregating minimum and maximum lock hold and wait times
accross cpus, the values are added, instead of selecting the
minimum and maximum.Signed-off-by: Frank Rowand
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
13 Nov, 2009
1 commit
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Lockdep events subsystem gathers various locking related events
such as a request, release, contention or acquisition of a lock.The name of this event subsystem is a bit of a misnomer since
these events are not quite related to lockdep but more generally
to locking, ie: these events are not reporting lock dependencies
or possible deadlock scenario but pure locking events.Hence this rename.
Signed-off-by: Frederic Weisbecker
Acked-by: Peter Zijlstra
Acked-by: Hitoshi Mitake
Cc: Arnaldo Carvalho de Melo
Cc: Mike Galbraith
Cc: Paul Mackerras
Cc: Steven Rostedt
Cc: Li Zefan
LKML-Reference:
Signed-off-by: Ingo Molnar
29 Oct, 2009
1 commit
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This patch updates percpu related symbols under kernel/ and mm/ such
that percpu symbols are unique and don't clash with local symbols.
This serves two purposes of decreasing the possibility of global
percpu symbol collision and allowing dropping per_cpu__ prefix from
percpu symbols.* kernel/lockdep.c: s/lock_stats/cpu_lock_stats/
* kernel/sched.c: s/init_rq_rt/init_rt_rq_var/ (any better idea?)
s/sched_group_cpus/sched_groups/* kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a
* kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/
s/watchdog_task/softlockup_watchdog/
s/timestamp/ts/ for local variables* kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/
* mm/slab.c: s/reap_work/slab_reap_work/
s/reap_node/slab_reap_node/* mm/vmstat.c: local variable changed to avoid collision with vmstat_work
Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
which cause name clashes" patch.Signed-off-by: Tejun Heo
Acked-by: (slab/vmstat) Christoph Lameter
Reviewed-by: Christoph Lameter
Cc: Rusty Russell
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: Andrew Morton
Cc: Nick Piggin
09 Oct, 2009
1 commit
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Some tracepoint magic (TRACE_EVENT(lock_acquired)) relies on
the fact that lock hold times are positive and uses div64 on
that. That triggered a build warning on MIPS, and probably
causes bad output in certain circumstances as well.Make it truly positive.
Reported-by: Andrew Morton
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
23 Sep, 2009
1 commit
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This allows lockdep to locate symbols that are in arch-specific data
sections (such as data in Blackfin on-chip SRAM regions).Signed-off-by: Mike Frysinger
Cc: Ingo Molnar
Cc: Robin Getz
Cc: Sam Ravnborg
Cc: Peter Zijlstra
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Aug, 2009
1 commit
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Since lockdep has introduced BFS to avoid recursion, statistics
for recursion does not make any sense now. So remove them.Signed-off-by: Ming Lei
Cc: a.p.zijlstra@chello.nl
LKML-Reference:
Signed-off-by: Ingo Molnar
02 Aug, 2009
6 commits
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The unit is KB, so sizeof(struct circular_queue) should be
divided by 1024.Signed-off-by: Ming Lei
Cc: akpm@linux-foundation.org
Cc: torvalds@linux-foundation.org
Cc: davem@davemloft.net
Cc: Ming Lei
Cc: a.p.zijlstra@chello.nl
LKML-Reference:
Signed-off-by: Ingo Molnar -
We still can apply DaveM's generation count optimization to
BFS, based on the following idea:- before doing each BFS, increase the global generation id
by 1- if one node in the graph has been visited, mark it as
visited by storing the current global generation id into
the node's dep_gen_id field- so we can decide if one node has been visited already, by
comparing the node's dep_gen_id with the global generation id.By applying DaveM's generation count optimization to current
implementation of BFS, we gain the following advantages:- we save MAX_LOCKDEP_ENTRIES/8 bytes memory;
- we remove the bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES);
in each BFS, which is very time-consuming since
MAX_LOCKDEP_ENTRIES may be very large.(16384UL)Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
Cc: "David S. Miller"
LKML-Reference:
Signed-off-by: Ingo Molnar -
spin_lock_nest_lock() allows to take many instances of the same
class, this can easily lead to overflow of MAX_LOCK_DEPTH.To avoid this overflow, we'll stop accounting instances but
start reference counting the class in the held_lock structure.[ We could maintain a list of instances, if we'd move the hlock
stuff into __lock_acquired(), but that would require
significant modifications to the current code. ]We restrict this mode to spin_lock_nest_lock() only, because it
degrades the lockdep quality due to lost of instance.For lockstat this means we don't track lock statistics for any
but the first lock in the series.Currently nesting is limited to 11 bits because that was the
spare space available in held_lock. This yields a 2048
instances maximium.Signed-off-by: Peter Zijlstra
Cc: Marcelo Tosatti
Cc: Linus Torvalds
Signed-off-by: Ingo Molnar -
Add a lockdep helper to validate that we indeed are the owner
of a lock.Signed-off-by: Peter Zijlstra
Signed-off-by: Ingo Molnar -
fixes a few comments and whitespaces that annoyed me.
Signed-off-by: Peter Zijlstra
Signed-off-by: Ingo Molnar -
Truncate stupid -1 entries in backtraces.
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
24 Jul, 2009
10 commits
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Some cleanups of the lockdep code after the BFS series:
- Remove the last traces of the generation id
- Fixup comment style
- Move the bfs routines into lockdep.c
- Cleanup the bfs routines[ tom.leiming@gmail.com: Fix crash ]
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
Add BFS statistics to the existing lockdep stats.
Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
Also account the BFS memory usage.
Signed-off-by: Ming Lei
[ fix build for !PROVE_LOCKING ]
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
Implement lockdep_count_{for,back}ward using BFS.
Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
Since the shortest lock dependencies' path may be obtained by BFS,
we print the shortest one by print_shortest_lock_dependencies().Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
This patch uses BFS to implement find_usage_*wards(),which
was originally writen by DFS.Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
This patch uses BFS to implement check_noncircular() and
prints the generated shortest circle if exists.Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
1,introduce match() to BFS in order to make it usable to
match different pattern;2,also rename some functions to make them more suitable.
Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
1,replace %MAX_CIRCULAR_QUE_SIZE with &(MAX_CIRCULAR_QUE_SIZE-1)
since we define MAX_CIRCULAR_QUE_SIZE as power of 2;2,use bitmap to mark if a lock is accessed in BFS in order to
clear it quickly, because we may search a graph many times.Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
Currently lockdep will print the 1st circle detected if it
exists when acquiring a new (next) lock.This patch prints the shortest path from the next lock to be
acquired to the previous held lock if a circle is found.The patch still uses the current method to check circle, and
once the circle is found, breadth-first search algorithem is
used to compute the shortest path from the next lock to the
previous lock in the forward lock dependency graph.Printing the shortest path will shorten the dependency chain,
and make troubleshooting for possible circular locking easier.Signed-off-by: Ming Lei
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
07 May, 2009
1 commit
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Merge reason: tracing/core was on a .30-rc1 base and was missing out on
on a handful of tracing fixes present in .30-rc5-almost.Signed-off-by: Ingo Molnar
18 Apr, 2009
1 commit
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Steven Rostedt reported:
> OK, I think I figured this bug out. This is a lockdep issue with respect
> to tracepoints.
>
> The trace points in lockdep are called all the time. Outside the lockdep
> logic. But if lockdep were to trigger an error / warning (which this run
> did) we might be in trouble. For new locks, like the dentry->d_lock, that
> are created, they will not get a name:
>
> void lockdep_init_map(struct lockdep_map *lock, const char *name,
> struct lock_class_key *key, int subclass)
> {
> if (unlikely(!debug_locks))
> return;
>
> When a problem is found by lockdep, debug_locks becomes false. Thus we
> stop allocating names for locks. This dentry->d_lock I had, now has no
> name. Worse yet, I have CONFIG_DEBUG_VM set, that scrambles non
> initialized memory. Thus, when the trace point was hit, it had junk for
> the lock->name, and the machine crashed.Ah, nice catch. I think we should put at least the name in regardless.
Ensure we at least initialize the trivial entries of the depmap so that
they can be relied upon, even when lockdep itself decided to pack up and
go home.[ Impact: fix lock tracing after lockdep warnings. ]
Reported-by: Steven Rostedt
Signed-off-by: Peter Zijlstra
Acked-by: Steven Rostedt
Cc: Andrew Morton
Cc: Frederic Weisbecker
LKML-Reference:
Signed-off-by: Ingo Molnar
15 Apr, 2009
2 commits
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Impact: clean up
Create a sub directory in include/trace called events to keep the
trace point headers in their own separate directory. Only headers that
declare trace points should be defined in this directory.Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Neil Horman
Cc: Zhao Lei
Cc: Eduard - Gabriel Munteanu
Cc: Pekka Enberg
Signed-off-by: Steven Rostedt -
This patch lowers the number of places a developer must modify to add
new tracepoints. The current method to add a new tracepoint
into an existing system is to write the trace point macro in the
trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or
DECLARE_TRACE, then they must add the same named item into the C file
with the macro DEFINE_TRACE(name) and then add the trace point.This change cuts out the needing to add the DEFINE_TRACE(name).
Every file that uses the tracepoint must still include the trace/.h
file, but the one C file must also add a define before the including
of that file.#define CREATE_TRACE_POINTS
#includeThis will cause the trace/mytrace.h file to also produce the C code
necessary to implement the trace point.Note, if more than one trace/.h is used to create the C code
it is best to list them all together.#define CREATE_TRACE_POINTS
#include
#include
#includeThanks to Mathieu Desnoyers and Christoph Hellwig for coming up with
the cleaner solution of the define above the includes over my first
design to have the C code include a "special" header.This patch converts sched, irq and lockdep and skb to use this new
method.Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Neil Horman
Cc: Zhao Lei
Cc: Eduard - Gabriel Munteanu
Cc: Pekka Enberg
Signed-off-by: Steven Rostedt
10 Apr, 2009
1 commit
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While trying to optimize the new lock on reiserfs to replace
the bkl, I find the lock tracing very useful though it lacks
something important for performance (and latency) instrumentation:
the time a task waits for a lock.That's what this patch implements:
bash-4816 [000] 202.652815: lock_contended: lock_contended: &sb->s_type->i_mutex_key
bash-4816 [000] 202.652819: lock_acquired: &rq->lock (0.000 us)
-4787 [000] 202.652825: lock_acquired: &rq->lock (0.000 us)
-4787 [000] 202.652829: lock_acquired: &rq->lock (0.000 us)
bash-4816 [000] 202.652833: lock_acquired: &sb->s_type->i_mutex_key (16.005 us)As shown above, the "lock acquired" field is followed by the time
it has been waiting for the lock. Usually, a lock contended entry
is followed by a near lock_acquired entry with a non-zero time waited.Signed-off-by: Frederic Weisbecker
Acked-by: Peter Zijlstra
Cc: Steven Rostedt
LKML-Reference:
Signed-off-by: Ingo Molnar
07 Apr, 2009
1 commit
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* 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
lockdep: add stack dumps to asserts
hrtimer: fix rq->lock inversion (again)
02 Apr, 2009
1 commit
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Conflicts:
include/linux/slub_def.h
lib/Kconfig.debug
mm/slob.c
mm/slub.c
31 Mar, 2009
3 commits
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Have a better idea about exactly which loc causes a lockdep
limit overflow. Often it's a bug or inefficiency in that
subsystem.Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
Conflicts:
lib/Kconfig.debug -
Heiko reported that we grab the graph lock with irqs enabled.
Fix this by providng the same wrapper as all other lockdep entry
functions have.Reported-by: Heiko Carstens
Signed-off-by: Peter Zijlstra
Cc: Nick Piggin
LKML-Reference:
Signed-off-by: Ingo Molnar
13 Mar, 2009
1 commit
05 Mar, 2009
1 commit
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Impact: cleanup
The atomic debug modifiers are already defined in
kernel/lockdep_internals.h.Signed-off-by: David Rientjes
Acked-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
