linux-toradex.git/kernel/lockdep.c, branch v2.6.21

[PATCH] lockdep: debug_show_all_locks & debug_show_held_locks vs. debug_locks

2007-03-23T02:39:06+00:00

lockdep's data shouldn't be used when debug_locks == 0 because it's not
updated after this, so it's more misleading than helpful.

PS: probably lockdep's current-> fields should be reset after it turns
debug_locks off: so, after printing a bug report, but before return from
exported functions, but there are really a lot of these possibilities (e.g.
 after DEBUG_LOCKS_WARN_ON), so, something could be missed.  (Of course
direct use of this fields isn't recommended either.)

Reported-by: Folkert van Heusden 
Inspired-by: Oleg Nesterov 
Signed-off-by: Jarek Poplawski 
Acked-by: Peter Zijlstra 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fix section mismatch warning in lockdep

2007-03-01T22:53:37+00:00

lockdep_init() is marked __init but used in several places
outside __init code. This causes following warnings:
$ scripts/mod/modpost kernel/lockdep.o
WARNING: kernel/built-in.o - Section mismatch: reference to .init.text:lockdep_init from .text.lockdep_init_map after 'lockdep_init_map' (at offset 0x105)
WARNING: kernel/built-in.o - Section mismatch: reference to .init.text:lockdep_init from .text.lockdep_reset_lock after 'lockdep_reset_lock' (at offset 0x35)
WARNING: kernel/built-in.o - Section mismatch: reference to .init.text:lockdep_init from .text.__lock_acquire after '__lock_acquire' (at offset 0xb2)

The warnings are less obviously due to heavy inlining by gcc - this is not
altered.

Fix the section mismatch warnings by removing the __init marking, which
seems obviously wrong.

Signed-off-by: Sam Ravnborg 
Acked-by: Ingo Molnar 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: debug_locks check after check_chain_key

2007-02-21T01:10:14+00:00

In __lock_acquire check_chain_key can turn off debug_locks, so check is
needed to assure proper return code.

Signed-off-by: Jarek Poplawski 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: add graph depth information to /proc/lockdep

2007-02-11T18:51:26+00:00

Generate locking graph information into /proc/lockdep, for lock hierarchy
documentation and visualization purposes.

sample output:

 c089fd5c OPS:     138 FD:   14 BD:    1 --..: &tty->termios_mutex
  -> [c07a3430] tty_ldisc_lock
  -> [c07a37f0] &port_lock_key
  -> [c07afdc0] &rq->rq_lock_key#2

The lock classes listed are all the first-hop lock dependencies that
lockdep has seen so far.

Signed-off-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: more unlock-on-error fixes

2007-02-11T18:51:26+00:00

- returns after DEBUG_LOCKS_WARN_ON added in 3 places

- debug_locks checking after lookup_chain_cache() added in
  __lock_acquire()

- locking for testing and changing global variable max_lockdep_depth
  added in __lock_acquire()

From: Ingo Molnar 

My __acquire_lock() cleanup introduced a locking bug: on SMP systems we'd
release a non-owned graph lock.  Fix this by moving the graph unlock back,
and by leaving the max_lockdep_depth variable update possibly racy.  (we
dont care, it's just statistics)

Also add some minimal debugging code to graph_unlock()/graph_lock(),
which caught this locking bug.

Signed-off-by: Jarek Poplawski 
Signed-off-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: printk warning fix

2006-12-30T18:56:43+00:00

kernel/lockdep.c: In function `lookup_chain_cache':
kernel/lockdep.c:1339: warning: long long unsigned int format, u64 arg (arg 2)
kernel/lockdep.c:1344: warning: long long unsigned int format, u64 arg (arg 2)

Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: fix possible races while disabling lock-debugging

2006-12-13T17:05:50+00:00

Jarek Poplawski noticed that lockdep global state could be accessed in a
racy way if one CPU did a lockdep assert (shutting lockdep down), while the
other CPU would try to do something that changes its global state.

This patch fixes those races and cleans up lockdep's internal locking by
adding a graph_lock()/graph_unlock()/debug_locks_off_graph_unlock helpers.

(Also note that as we all know the Linux kernel is, by definition, bug-free
and perfect, so this code never triggers, so these fixes are highly
theoretical.  I wrote this patch for aesthetic reasons alone.)

[akpm@osdl.org: build fix]
[jarkao2@o2.pl: build fix's refix]
Signed-off-by: Ingo Molnar 
Signed-off-by: Jarek Poplawski 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: print irq-trace info on asserts

2006-12-13T17:05:50+00:00

When we print an assert due to scheduling-in-atomic bugs, and if lockdep
is enabled, then the IRQ tracing information of lockdep can be printed
to pinpoint the code location that disabled interrupts. This saved me
quite a bit of debugging time in cases where the backtrace did not
identify the irq-disabling site well enough.

Signed-off-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: use chain hash on CONFIG_DEBUG_LOCKDEP too

2006-12-13T17:05:50+00:00

CONFIG_DEBUG_LOCKDEP is unacceptably slow because it does not utilize
the chain-hash. Turn the chain-hash back on in this case too.

Signed-off-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: clean up VERY_VERBOSE define

2006-12-13T17:05:50+00:00

Cleanup: the VERY_VERBOSE define was unnecessarily dependent on #ifdef VERBOSE
- while the VERBOSE switch is 0 or 1 (always defined).

Signed-off-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds