diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-30 17:17:35 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-30 17:17:35 -0700 |
commit | c4e1aa67ed9e4e542a064bc271ddbf152b677e91 (patch) | |
tree | 2a2ca00bed0fc22b4eb83db092c9178868d8f76b /Documentation | |
parent | cf2f7d7c90279cdbc12429de278f3d27ac2050ae (diff) | |
parent | 2f8501815256af8498904e68bd0984b1afffd6f8 (diff) |
Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (33 commits)
lockdep: fix deadlock in lockdep_trace_alloc
lockdep: annotate reclaim context (__GFP_NOFS), fix SLOB
lockdep: annotate reclaim context (__GFP_NOFS), fix
lockdep: build fix for !PROVE_LOCKING
lockstat: warn about disabled lock debugging
lockdep: use stringify.h
lockdep: simplify check_prev_add_irq()
lockdep: get_user_chars() redo
lockdep: simplify get_user_chars()
lockdep: add comments to mark_lock_irq()
lockdep: remove macro usage from mark_held_locks()
lockdep: fully reduce mark_lock_irq()
lockdep: merge the !_READ mark_lock_irq() helpers
lockdep: merge the _READ mark_lock_irq() helpers
lockdep: simplify mark_lock_irq() helpers #3
lockdep: further simplify mark_lock_irq() helpers
lockdep: simplify the mark_lock_irq() helpers
lockdep: split up mark_lock_irq()
lockdep: generate usage strings
lockdep: generate the state bit definitions
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/lockdep-design.txt | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/Documentation/lockdep-design.txt b/Documentation/lockdep-design.txt index 48877301815..938ea22f2cc 100644 --- a/Documentation/lockdep-design.txt +++ b/Documentation/lockdep-design.txt @@ -27,33 +27,37 @@ lock-class. State ----- -The validator tracks lock-class usage history into 5 separate state bits: +The validator tracks lock-class usage history into 4n + 1 separate state bits: -- 'ever held in hardirq context' [ == hardirq-safe ] -- 'ever held in softirq context' [ == softirq-safe ] -- 'ever held with hardirqs enabled' [ == hardirq-unsafe ] -- 'ever held with softirqs and hardirqs enabled' [ == softirq-unsafe ] +- 'ever held in STATE context' +- 'ever head as readlock in STATE context' +- 'ever head with STATE enabled' +- 'ever head as readlock with STATE enabled' + +Where STATE can be either one of (kernel/lockdep_states.h) + - hardirq + - softirq + - reclaim_fs - 'ever used' [ == !unused ] -When locking rules are violated, these 4 state bits are presented in the -locking error messages, inside curlies. A contrived example: +When locking rules are violated, these state bits are presented in the +locking error messages, inside curlies. A contrived example: modprobe/2287 is trying to acquire lock: - (&sio_locks[i].lock){--..}, at: [<c02867fd>] mutex_lock+0x21/0x24 + (&sio_locks[i].lock){-.-...}, at: [<c02867fd>] mutex_lock+0x21/0x24 but task is already holding lock: - (&sio_locks[i].lock){--..}, at: [<c02867fd>] mutex_lock+0x21/0x24 + (&sio_locks[i].lock){-.-...}, at: [<c02867fd>] mutex_lock+0x21/0x24 -The bit position indicates hardirq, softirq, hardirq-read, -softirq-read respectively, and the character displayed in each -indicates: +The bit position indicates STATE, STATE-read, for each of the states listed +above, and the character displayed in each indicates: '.' acquired while irqs disabled '+' acquired in irq context '-' acquired with irqs enabled - '?' read acquired in irq context with irqs enabled. + '?' acquired in irq context with irqs enabled. Unused mutexes cannot be part of the cause of an error. |