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author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2009-05-08 18:29:27 -0700 |
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committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2009-05-08 18:29:27 -0700 |
commit | d585a021c0b10b0477d6b608c53e1feb8cde0507 (patch) | |
tree | 5ca059da1db7f15d4b29427644ad9c08270c885c /Documentation/lockdep-design.txt | |
parent | 84e5b0d00f8f84c4ae226be131d4bebbcee88bd3 (diff) | |
parent | 091bf7624d1c90cec9e578a18529f615213ff847 (diff) |
Merge commit 'v2.6.30-rc5' into next
Diffstat (limited to 'Documentation/lockdep-design.txt')
-rw-r--r-- | Documentation/lockdep-design.txt | 36 |
1 files changed, 20 insertions, 16 deletions
diff --git a/Documentation/lockdep-design.txt b/Documentation/lockdep-design.txt index 48877301815..e20d913d591 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 while irqs disabled and not in irq context + '-' acquired in irq context + '+' acquired with irqs enabled + '?' acquired in irq context with irqs enabled. Unused mutexes cannot be part of the cause of an error. |