From cf40bd16fdad42c053040bcd3988f5fdedbb6c57 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 21 Jan 2009 08:12:39 +0100 Subject: lockdep: annotate reclaim context (__GFP_NOFS) Here is another version, with the incremental patch rolled up, and added reclaim context annotation to kswapd, and allocation tracing to slab allocators (which may only ever reach the page allocator in rare cases, so it is good to put annotations here too). Haven't tested this version as such, but it should be getting closer to merge worthy ;) -- After noticing some code in mm/filemap.c accidentally perform a __GFP_FS allocation when it should not have been, I thought it might be a good idea to try to catch this kind of thing with lockdep. I coded up a little idea that seems to work. Unfortunately the system has to actually be in __GFP_FS page reclaim, then take the lock, before it will mark it. But at least that might still be some orders of magnitude more common (and more debuggable) than an actual deadlock condition, so we have some improvement I hope (the concept is no less complete than discovery of a lock's interrupt contexts). I guess we could even do the same thing with __GFP_IO (normal reclaim), and even GFP_NOIO locks too... but filesystems will have the most locks and fiddly code paths, so let's start there and see how it goes. It *seems* to work. I did a quick test. ================================= [ INFO: inconsistent lock state ] 2.6.28-rc6-00007-ged31348-dirty #26 --------------------------------- inconsistent {in-reclaim-W} -> {ov-reclaim-W} usage. modprobe/8526 [HC0[0]:SC0[0]:HE1:SE1] takes: (testlock){--..}, at: [] brd_init+0x55/0x216 [brd] {in-reclaim-W} state was registered at: [] __lock_acquire+0x75b/0x1a60 [] lock_acquire+0x91/0xc0 [] mutex_lock_nested+0xb1/0x310 [] brd_init+0x2b/0x216 [brd] [] _stext+0x3b/0x170 [] sys_init_module+0xaf/0x1e0 [] system_call_fastpath+0x16/0x1b [] 0xffffffffffffffff irq event stamp: 3929 hardirqs last enabled at (3929): [] mutex_lock_nested+0x285/0x310 hardirqs last disabled at (3928): [] mutex_lock_nested+0x59/0x310 softirqs last enabled at (3732): [] sk_filter+0x83/0xe0 softirqs last disabled at (3730): [] sk_filter+0x16/0xe0 other info that might help us debug this: 1 lock held by modprobe/8526: #0: (testlock){--..}, at: [] brd_init+0x55/0x216 [brd] stack backtrace: Pid: 8526, comm: modprobe Not tainted 2.6.28-rc6-00007-ged31348-dirty #26 Call Trace: [] print_usage_bug+0x193/0x1d0 [] mark_lock+0xaf0/0xca0 [] mark_held_locks+0x55/0xc0 [] ? brd_init+0x0/0x216 [brd] [] trace_reclaim_fs+0x2a/0x60 [] __alloc_pages_internal+0x475/0x580 [] ? mutex_lock_nested+0x26e/0x310 [] ? brd_init+0x0/0x216 [brd] [] brd_init+0x6a/0x216 [brd] [] ? brd_init+0x0/0x216 [brd] [] _stext+0x3b/0x170 [] ? mutex_unlock+0x9/0x10 [] ? __mutex_unlock_slowpath+0x10d/0x180 [] ? trace_hardirqs_on_caller+0x12c/0x190 [] sys_init_module+0xaf/0x1e0 [] system_call_fastpath+0x16/0x1b Signed-off-by: Nick Piggin Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep_proc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/lockdep_proc.c') diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 13716b813896..b84a1dfa9077 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -84,7 +84,7 @@ static int l_show(struct seq_file *m, void *v) { struct lock_class *class = v; struct lock_list *entry; - char c1, c2, c3, c4; + char c1, c2, c3, c4, c5, c6; if (v == SEQ_START_TOKEN) { seq_printf(m, "all lock classes:\n"); @@ -100,8 +100,8 @@ static int l_show(struct seq_file *m, void *v) seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class)); #endif - get_usage_chars(class, &c1, &c2, &c3, &c4); - seq_printf(m, " %c%c%c%c", c1, c2, c3, c4); + get_usage_chars(class, &c1, &c2, &c3, &c4, &c5, &c6); + seq_printf(m, " %c%c%c%c%c%c", c1, c2, c3, c4, c5, c6); seq_printf(m, ": "); print_name(m, class); -- cgit v1.2.3 From 4fc95e867f1e75351b89db3c68212dfcce7ea563 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 22 Jan 2009 13:10:52 +0100 Subject: lockdep: sanitize bit names s/\(LOCKF\?_ENABLED_[^ ]*\)S\(_READ\)\?\>/\1\2/g So that the USED_IN and ENABLED have the same names. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 22 ++++++------- kernel/lockdep.c | 84 ++++++++++++++++++++++++------------------------- kernel/lockdep_proc.c | 12 +++---- 3 files changed, 59 insertions(+), 59 deletions(-) (limited to 'kernel/lockdep_proc.c') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index cc97bdbc7969..da2e2b25b3b2 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -28,14 +28,14 @@ enum lock_usage_bit LOCK_USED_IN_HARDIRQ, LOCK_USED_IN_SOFTIRQ, LOCK_USED_IN_RECLAIM_FS, - LOCK_ENABLED_SOFTIRQS, - LOCK_ENABLED_HARDIRQS, + LOCK_ENABLED_SOFTIRQ, + LOCK_ENABLED_HARDIRQ, LOCK_HELD_OVER_RECLAIM_FS, LOCK_USED_IN_HARDIRQ_READ, LOCK_USED_IN_SOFTIRQ_READ, LOCK_USED_IN_RECLAIM_FS_READ, - LOCK_ENABLED_SOFTIRQS_READ, - LOCK_ENABLED_HARDIRQS_READ, + LOCK_ENABLED_SOFTIRQ_READ, + LOCK_ENABLED_HARDIRQ_READ, LOCK_HELD_OVER_RECLAIM_FS_READ, LOCK_USAGE_STATES }; @@ -47,22 +47,22 @@ enum lock_usage_bit #define LOCKF_USED_IN_HARDIRQ (1 << LOCK_USED_IN_HARDIRQ) #define LOCKF_USED_IN_SOFTIRQ (1 << LOCK_USED_IN_SOFTIRQ) #define LOCKF_USED_IN_RECLAIM_FS (1 << LOCK_USED_IN_RECLAIM_FS) -#define LOCKF_ENABLED_HARDIRQS (1 << LOCK_ENABLED_HARDIRQS) -#define LOCKF_ENABLED_SOFTIRQS (1 << LOCK_ENABLED_SOFTIRQS) +#define LOCKF_ENABLED_HARDIRQ (1 << LOCK_ENABLED_HARDIRQ) +#define LOCKF_ENABLED_SOFTIRQ (1 << LOCK_ENABLED_SOFTIRQ) #define LOCKF_HELD_OVER_RECLAIM_FS (1 << LOCK_HELD_OVER_RECLAIM_FS) -#define LOCKF_ENABLED_IRQS (LOCKF_ENABLED_HARDIRQS | LOCKF_ENABLED_SOFTIRQS) +#define LOCKF_ENABLED_IRQ (LOCKF_ENABLED_HARDIRQ | LOCKF_ENABLED_SOFTIRQ) #define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ) #define LOCKF_USED_IN_HARDIRQ_READ (1 << LOCK_USED_IN_HARDIRQ_READ) #define LOCKF_USED_IN_SOFTIRQ_READ (1 << LOCK_USED_IN_SOFTIRQ_READ) #define LOCKF_USED_IN_RECLAIM_FS_READ (1 << LOCK_USED_IN_RECLAIM_FS_READ) -#define LOCKF_ENABLED_HARDIRQS_READ (1 << LOCK_ENABLED_HARDIRQS_READ) -#define LOCKF_ENABLED_SOFTIRQS_READ (1 << LOCK_ENABLED_SOFTIRQS_READ) +#define LOCKF_ENABLED_HARDIRQ_READ (1 << LOCK_ENABLED_HARDIRQ_READ) +#define LOCKF_ENABLED_SOFTIRQ_READ (1 << LOCK_ENABLED_SOFTIRQ_READ) #define LOCKF_HELD_OVER_RECLAIM_FS_READ (1 << LOCK_HELD_OVER_RECLAIM_FS_READ) -#define LOCKF_ENABLED_IRQS_READ \ - (LOCKF_ENABLED_HARDIRQS_READ | LOCKF_ENABLED_SOFTIRQS_READ) +#define LOCKF_ENABLED_IRQ_READ \ + (LOCKF_ENABLED_HARDIRQ_READ | LOCKF_ENABLED_SOFTIRQ_READ) #define LOCKF_USED_IN_IRQ_READ \ (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ) diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 977f940fd562..32f944752b18 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -450,12 +450,12 @@ static const char *usage_str[] = [LOCK_USED] = "initial-use ", [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W", [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W", - [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W", - [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W", + [LOCK_ENABLED_SOFTIRQ] = "softirq-on-W", + [LOCK_ENABLED_HARDIRQ] = "hardirq-on-W", [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R", [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R", - [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R", - [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R", + [LOCK_ENABLED_SOFTIRQ_READ] = "softirq-on-R", + [LOCK_ENABLED_HARDIRQ_READ] = "hardirq-on-R", [LOCK_USED_IN_RECLAIM_FS] = "in-reclaim-W", [LOCK_USED_IN_RECLAIM_FS_READ] = "in-reclaim-R", [LOCK_HELD_OVER_RECLAIM_FS] = "ov-reclaim-W", @@ -476,28 +476,28 @@ get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) *c1 = '+'; else - if (class->usage_mask & LOCKF_ENABLED_HARDIRQS) + if (class->usage_mask & LOCKF_ENABLED_HARDIRQ) *c1 = '-'; if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) *c2 = '+'; else - if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS) + if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ) *c2 = '-'; - if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) + if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ) *c3 = '-'; if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) { *c3 = '+'; - if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) + if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ) *c3 = '?'; } - if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) + if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ) *c4 = '-'; if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) { *c4 = '+'; - if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) + if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ) *c4 = '?'; } @@ -1296,7 +1296,7 @@ check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, * forwards-subgraph starting at : */ if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, - LOCK_ENABLED_HARDIRQS, "hard")) + LOCK_ENABLED_HARDIRQ, "hard")) return 0; /* @@ -1306,7 +1306,7 @@ check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, * forwards-subgraph starting at : */ if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, - LOCK_ENABLED_HARDIRQS, "hard-read")) + LOCK_ENABLED_HARDIRQ, "hard-read")) return 0; /* @@ -1316,7 +1316,7 @@ check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, * forwards-subgraph starting at : */ if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, - LOCK_ENABLED_SOFTIRQS, "soft")) + LOCK_ENABLED_SOFTIRQ, "soft")) return 0; /* * Prove that the new dependency does not connect a softirq-safe-read @@ -1325,7 +1325,7 @@ check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, * forwards-subgraph starting at : */ if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, - LOCK_ENABLED_SOFTIRQS, "soft")) + LOCK_ENABLED_SOFTIRQ, "soft")) return 0; /* @@ -2008,17 +2008,17 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, switch(new_bit) { case LOCK_USED_IN_HARDIRQ: - if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) + if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQ)) return 0; if (!valid_state(curr, this, new_bit, - LOCK_ENABLED_HARDIRQS_READ)) + LOCK_ENABLED_HARDIRQ_READ)) return 0; /* * just marked it hardirq-safe, check that this lock * took no hardirq-unsafe lock in the past: */ if (!check_usage_forwards(curr, this, - LOCK_ENABLED_HARDIRQS, "hard")) + LOCK_ENABLED_HARDIRQ, "hard")) return 0; #if STRICT_READ_CHECKS /* @@ -2026,24 +2026,24 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, * took no hardirq-unsafe-read lock in the past: */ if (!check_usage_forwards(curr, this, - LOCK_ENABLED_HARDIRQS_READ, "hard-read")) + LOCK_ENABLED_HARDIRQ_READ, "hard-read")) return 0; #endif if (hardirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_USED_IN_SOFTIRQ: - if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) + if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQ)) return 0; if (!valid_state(curr, this, new_bit, - LOCK_ENABLED_SOFTIRQS_READ)) + LOCK_ENABLED_SOFTIRQ_READ)) return 0; /* * just marked it softirq-safe, check that this lock * took no softirq-unsafe lock in the past: */ if (!check_usage_forwards(curr, this, - LOCK_ENABLED_SOFTIRQS, "soft")) + LOCK_ENABLED_SOFTIRQ, "soft")) return 0; #if STRICT_READ_CHECKS /* @@ -2051,7 +2051,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, * took no softirq-unsafe-read lock in the past: */ if (!check_usage_forwards(curr, this, - LOCK_ENABLED_SOFTIRQS_READ, "soft-read")) + LOCK_ENABLED_SOFTIRQ_READ, "soft-read")) return 0; #endif if (softirq_verbose(hlock_class(this))) @@ -2083,27 +2083,27 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, ret = 2; break; case LOCK_USED_IN_HARDIRQ_READ: - if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) + if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQ)) return 0; /* * just marked it hardirq-read-safe, check that this lock * took no hardirq-unsafe lock in the past: */ if (!check_usage_forwards(curr, this, - LOCK_ENABLED_HARDIRQS, "hard")) + LOCK_ENABLED_HARDIRQ, "hard")) return 0; if (hardirq_verbose(hlock_class(this))) ret = 2; break; case LOCK_USED_IN_SOFTIRQ_READ: - if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) + if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQ)) return 0; /* * just marked it softirq-read-safe, check that this lock * took no softirq-unsafe lock in the past: */ if (!check_usage_forwards(curr, this, - LOCK_ENABLED_SOFTIRQS, "soft")) + LOCK_ENABLED_SOFTIRQ, "soft")) return 0; if (softirq_verbose(hlock_class(this))) ret = 2; @@ -2121,7 +2121,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, if (reclaim_verbose(hlock_class(this))) ret = 2; break; - case LOCK_ENABLED_HARDIRQS: + case LOCK_ENABLED_HARDIRQ: if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) return 0; if (!valid_state(curr, this, new_bit, @@ -2147,7 +2147,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, if (hardirq_verbose(hlock_class(this))) ret = 2; break; - case LOCK_ENABLED_SOFTIRQS: + case LOCK_ENABLED_SOFTIRQ: if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) return 0; if (!valid_state(curr, this, new_bit, @@ -2199,7 +2199,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, if (reclaim_verbose(hlock_class(this))) ret = 2; break; - case LOCK_ENABLED_HARDIRQS_READ: + case LOCK_ENABLED_HARDIRQ_READ: if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) return 0; #if STRICT_READ_CHECKS @@ -2214,7 +2214,7 @@ static int mark_lock_irq(struct task_struct *curr, struct held_lock *this, if (hardirq_verbose(hlock_class(this))) ret = 2; break; - case LOCK_ENABLED_SOFTIRQS_READ: + case LOCK_ENABLED_SOFTIRQ_READ: if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) return 0; #if STRICT_READ_CHECKS @@ -2274,16 +2274,16 @@ mark_held_locks(struct task_struct *curr, enum mark_type mark) switch (mark) { case HARDIRQ: if (hlock->read) - usage_bit = LOCK_ENABLED_HARDIRQS_READ; + usage_bit = LOCK_ENABLED_HARDIRQ_READ; else - usage_bit = LOCK_ENABLED_HARDIRQS; + usage_bit = LOCK_ENABLED_HARDIRQ; break; case SOFTIRQ: if (hlock->read) - usage_bit = LOCK_ENABLED_SOFTIRQS_READ; + usage_bit = LOCK_ENABLED_SOFTIRQ_READ; else - usage_bit = LOCK_ENABLED_SOFTIRQS; + usage_bit = LOCK_ENABLED_SOFTIRQ; break; case RECLAIM_FS: @@ -2520,19 +2520,19 @@ static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) if (!hlock->hardirqs_off) { if (hlock->read) { if (!mark_lock(curr, hlock, - LOCK_ENABLED_HARDIRQS_READ)) + LOCK_ENABLED_HARDIRQ_READ)) return 0; if (curr->softirqs_enabled) if (!mark_lock(curr, hlock, - LOCK_ENABLED_SOFTIRQS_READ)) + LOCK_ENABLED_SOFTIRQ_READ)) return 0; } else { if (!mark_lock(curr, hlock, - LOCK_ENABLED_HARDIRQS)) + LOCK_ENABLED_HARDIRQ)) return 0; if (curr->softirqs_enabled) if (!mark_lock(curr, hlock, - LOCK_ENABLED_SOFTIRQS)) + LOCK_ENABLED_SOFTIRQ)) return 0; } } @@ -2640,10 +2640,10 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, case LOCK_USED_IN_SOFTIRQ: case LOCK_USED_IN_HARDIRQ_READ: case LOCK_USED_IN_SOFTIRQ_READ: - case LOCK_ENABLED_HARDIRQS: - case LOCK_ENABLED_SOFTIRQS: - case LOCK_ENABLED_HARDIRQS_READ: - case LOCK_ENABLED_SOFTIRQS_READ: + case LOCK_ENABLED_HARDIRQ: + case LOCK_ENABLED_SOFTIRQ: + case LOCK_ENABLED_HARDIRQ_READ: + case LOCK_ENABLED_SOFTIRQ_READ: case LOCK_USED_IN_RECLAIM_FS: case LOCK_USED_IN_RECLAIM_FS_READ: case LOCK_HELD_OVER_RECLAIM_FS: diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index b84a1dfa9077..bd474fd9df9d 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -300,27 +300,27 @@ static int lockdep_stats_show(struct seq_file *m, void *v) nr_uncategorized++; if (class->usage_mask & LOCKF_USED_IN_IRQ) nr_irq_safe++; - if (class->usage_mask & LOCKF_ENABLED_IRQS) + if (class->usage_mask & LOCKF_ENABLED_IRQ) nr_irq_unsafe++; if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) nr_softirq_safe++; - if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS) + if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ) nr_softirq_unsafe++; if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) nr_hardirq_safe++; - if (class->usage_mask & LOCKF_ENABLED_HARDIRQS) + if (class->usage_mask & LOCKF_ENABLED_HARDIRQ) nr_hardirq_unsafe++; if (class->usage_mask & LOCKF_USED_IN_IRQ_READ) nr_irq_read_safe++; - if (class->usage_mask & LOCKF_ENABLED_IRQS_READ) + if (class->usage_mask & LOCKF_ENABLED_IRQ_READ) nr_irq_read_unsafe++; if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) nr_softirq_read_safe++; - if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) + if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ) nr_softirq_read_unsafe++; if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) nr_hardirq_read_safe++; - if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) + if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ) nr_hardirq_read_unsafe++; #ifdef CONFIG_PROVE_LOCKING -- cgit v1.2.3 From f510b233cfc7bfd57b6007071c52aa42e3d16b06 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 22 Jan 2009 17:53:47 +0100 Subject: lockdep: get_user_chars() redo Generic, states independent, get_user_chars(). Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- Documentation/lockdep-design.txt | 30 +++++++++++++++++------------- kernel/lockdep.c | 24 ++++++++++++------------ kernel/lockdep_internals.h | 7 ++++--- kernel/lockdep_proc.c | 6 +++--- 4 files changed, 36 insertions(+), 31 deletions(-) (limited to 'kernel/lockdep_proc.c') diff --git a/Documentation/lockdep-design.txt b/Documentation/lockdep-design.txt index 488773018152..938ea22f2cc0 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: [] mutex_lock+0x21/0x24 + (&sio_locks[i].lock){-.-...}, at: [] mutex_lock+0x21/0x24 but task is already holding lock: - (&sio_locks[i].lock){--..}, at: [] mutex_lock+0x21/0x24 + (&sio_locks[i].lock){-.-...}, at: [] 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. diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 1b4ee3c0b789..22ced8d4912f 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -487,25 +487,25 @@ static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) return c; } -void -get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, - char *c4, char *c5, char *c6) +void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) { - *c1 = get_usage_char(class, LOCK_USED_IN_HARDIRQ); - *c2 = get_usage_char(class, LOCK_USED_IN_SOFTITQ); - *c3 = get_usage_char(class, LOCK_USED_IN_HARDIRQ_READ); - *c4 = get_usage_char(class, LOCK_USED_IN_SOFTITQ_READ); + int i = 0; - *c5 = get_usage_char(class, LOCK_USED_IN_RECLAIM_FS); - *c6 = get_usage_char(class, LOCK_USED_IN_RECLAIM_FS_READ); +#define LOCKDEP_STATE(__STATE) \ + usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ + usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); +#include "lockdep_states.h" +#undef LOCKDEP_STATE + + usage[i] = '\0'; } static void print_lock_name(struct lock_class *class) { - char str[KSYM_NAME_LEN], c1, c2, c3, c4, c5, c6; + char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; const char *name; - get_usage_chars(class, &c1, &c2, &c3, &c4, &c5, &c6); + get_usage_chars(class, usage); name = class->name; if (!name) { @@ -518,7 +518,7 @@ static void print_lock_name(struct lock_class *class) if (class->subclass) printk("/%d", class->subclass); } - printk("){%c%c%c%c%c%c}", c1, c2, c3, c4, c5, c6); + printk("){%s}", usage); } static void print_lockdep_cache(struct lockdep_map *lock) diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h index 7e653e66ce5a..a2cc7e9a6e84 100644 --- a/kernel/lockdep_internals.h +++ b/kernel/lockdep_internals.h @@ -70,9 +70,10 @@ enum { extern struct list_head all_lock_classes; extern struct lock_chain lock_chains[]; -extern void -get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, - char *c4, char *c5, char *c6); +#define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2) + +extern void get_usage_chars(struct lock_class *class, + char usage[LOCK_USAGE_CHARS]); extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str); diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index bd474fd9df9d..b51064ce564a 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -84,7 +84,7 @@ static int l_show(struct seq_file *m, void *v) { struct lock_class *class = v; struct lock_list *entry; - char c1, c2, c3, c4, c5, c6; + char usage[LOCK_USAGE_CHARS]; if (v == SEQ_START_TOKEN) { seq_printf(m, "all lock classes:\n"); @@ -100,8 +100,8 @@ static int l_show(struct seq_file *m, void *v) seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class)); #endif - get_usage_chars(class, &c1, &c2, &c3, &c4, &c5, &c6); - seq_printf(m, " %c%c%c%c%c%c", c1, c2, c3, c4, c5, c6); + get_usage_chars(class, usage); + seq_printf(m, " %s", usage); seq_printf(m, ": "); print_name(m, class); -- cgit v1.2.3 From 9833f8cb952b9aa3f98a71e7bef8820cee3261a0 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 14 Feb 2009 16:59:04 +0100 Subject: lockstat: warn about disabled lock debugging Avoid confusion and clearly state lock debugging got disabled. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/lockdep_proc.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/lockdep_proc.c') diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index b51064ce564a..d7135aa2d2c4 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -601,6 +601,10 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data) static void seq_header(struct seq_file *m) { seq_printf(m, "lock_stat version 0.3\n"); + + if (unlikely(!debug_locks)) + seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n"); + seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1)); seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s " "%14s %14s\n", -- cgit v1.2.3