diff options
author | Johannes Berg <johannes@sipsolutions.net> | 2007-10-19 08:39:55 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-19 20:53:38 +0200 |
commit | 4e6045f134784f4b158b3c0f7a282b04bd816887 (patch) | |
tree | 3304628f666c8524accd10f40da48cfba8b08608 /include | |
parent | Make access to task's nsproxy lighter (diff) | |
download | linux-4e6045f134784f4b158b3c0f7a282b04bd816887.tar.xz linux-4e6045f134784f4b158b3c0f7a282b04bd816887.zip |
workqueue: debug flushing deadlocks with lockdep
In the following scenario:
code path 1:
my_function() -> lock(L1); ...; flush_workqueue(); ...
code path 2:
run_workqueue() -> my_work() -> ...; lock(L1); ...
you can get a deadlock when my_work() is queued or running
but my_function() has acquired L1 already.
This patch adds a pseudo-lock to each workqueue to make lockdep
warn about this scenario.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/lockdep.h | 8 | ||||
-rw-r--r-- | include/linux/workqueue.h | 49 |
2 files changed, 54 insertions, 3 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index f6279f68a827..4c4d236ded18 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -276,6 +276,14 @@ extern void lockdep_init_map(struct lockdep_map *lock, const char *name, (lock)->dep_map.key, sub) /* + * To initialize a lockdep_map statically use this macro. + * Note that _name must not be NULL. + */ +#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ + { .name = (_name), .key = (void *)(_key), } + + +/* * Acquire a lock. * * Values for "read": diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index ce6badc98f6d..7daafdc2514b 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -8,6 +8,7 @@ #include <linux/timer.h> #include <linux/linkage.h> #include <linux/bitops.h> +#include <linux/lockdep.h> #include <asm/atomic.h> struct workqueue_struct; @@ -28,6 +29,9 @@ struct work_struct { #define WORK_STRUCT_WQ_DATA_MASK (~WORK_STRUCT_FLAG_MASK) struct list_head entry; work_func_t func; +#ifdef CONFIG_LOCKDEP + struct lockdep_map lockdep_map; +#endif }; #define WORK_DATA_INIT() ATOMIC_LONG_INIT(0) @@ -41,10 +45,23 @@ struct execute_work { struct work_struct work; }; +#ifdef CONFIG_LOCKDEP +/* + * NB: because we have to copy the lockdep_map, setting _key + * here is required, otherwise it could get initialised to the + * copy of the lockdep_map! + */ +#define __WORK_INIT_LOCKDEP_MAP(n, k) \ + .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k), +#else +#define __WORK_INIT_LOCKDEP_MAP(n, k) +#endif + #define __WORK_INITIALIZER(n, f) { \ .data = WORK_DATA_INIT(), \ .entry = { &(n).entry, &(n).entry }, \ .func = (f), \ + __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \ } #define __DELAYED_WORK_INITIALIZER(n, f) { \ @@ -76,12 +93,24 @@ struct execute_work { * assignment of the work data initializer allows the compiler * to generate better code. */ +#ifdef CONFIG_LOCKDEP +#define INIT_WORK(_work, _func) \ + do { \ + static struct lock_class_key __key; \ + \ + (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \ + lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0);\ + INIT_LIST_HEAD(&(_work)->entry); \ + PREPARE_WORK((_work), (_func)); \ + } while (0) +#else #define INIT_WORK(_work, _func) \ do { \ (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \ INIT_LIST_HEAD(&(_work)->entry); \ PREPARE_WORK((_work), (_func)); \ } while (0) +#endif #define INIT_DELAYED_WORK(_work, _func) \ do { \ @@ -118,9 +147,23 @@ struct execute_work { clear_bit(WORK_STRUCT_PENDING, work_data_bits(work)) -extern struct workqueue_struct *__create_workqueue(const char *name, - int singlethread, - int freezeable); +extern struct workqueue_struct * +__create_workqueue_key(const char *name, int singlethread, + int freezeable, struct lock_class_key *key); + +#ifdef CONFIG_LOCKDEP +#define __create_workqueue(name, singlethread, freezeable) \ +({ \ + static struct lock_class_key __key; \ + \ + __create_workqueue_key((name), (singlethread), \ + (freezeable), &__key); \ +}) +#else +#define __create_workqueue(name, singlethread, freezeable) \ + __create_workqueue_key((name), (singlethread), (freezeable), NULL) +#endif + #define create_workqueue(name) __create_workqueue((name), 0, 0) #define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1) #define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0) |