From 364f6afc4f5537b79cf454eb35cae92920676075 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 22 Jul 2019 11:24:40 -0700 Subject: locking/lockdep: Make it clear that what lock_class::key points at is not modified This patch does not change the behavior of the lockdep code. Signed-off-by: Bart Van Assche Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Waiman Long Cc: Will Deacon Link: https://lkml.kernel.org/r/20190722182443.216015-2-bvanassche@acm.org Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 0b0d7259276d..cdb3c2f06092 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -97,7 +97,7 @@ struct lock_class { */ struct list_head locks_after, locks_before; - struct lockdep_subclass_key *key; + const struct lockdep_subclass_key *key; unsigned int subclass; unsigned int dep_gen_id; -- cgit v1.2.3 From a2970421640bd9b6a78f2685d7750a791abdfd4e Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 22 Jul 2019 11:24:41 -0700 Subject: stacktrace: Constify 'entries' arguments Make it clear to humans and to the compiler that the stack trace ('entries') arguments are not modified. Signed-off-by: Bart Van Assche Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Waiman Long Cc: Will Deacon Link: https://lkml.kernel.org/r/20190722182443.216015-3-bvanassche@acm.org Signed-off-by: Ingo Molnar --- include/linux/stacktrace.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h index f0cfd12cb45e..83bd8cb475d7 100644 --- a/include/linux/stacktrace.h +++ b/include/linux/stacktrace.h @@ -9,9 +9,9 @@ struct task_struct; struct pt_regs; #ifdef CONFIG_STACKTRACE -void stack_trace_print(unsigned long *trace, unsigned int nr_entries, +void stack_trace_print(const unsigned long *trace, unsigned int nr_entries, int spaces); -int stack_trace_snprint(char *buf, size_t size, unsigned long *entries, +int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries, unsigned int nr_entries, int spaces); unsigned int stack_trace_save(unsigned long *store, unsigned int size, unsigned int skipnr); -- cgit v1.2.3 From 12593b7467f9130b64a6d4b6a26ed4ec217b6784 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 22 Jul 2019 11:24:42 -0700 Subject: locking/lockdep: Reduce space occupied by stack traces Although commit 669de8bda87b ("kernel/workqueue: Use dynamic lockdep keys for workqueues") unregisters dynamic lockdep keys when a workqueue is destroyed, a side effect of that commit is that all stack traces associated with the lockdep key are leaked when a workqueue is destroyed. Fix this by storing each unique stack trace once. Other changes in this patch are: - Use NULL instead of { .nr_entries = 0 } to represent 'no trace'. - Store a pointer to a stack trace in struct lock_class and struct lock_list instead of storing 'nr_entries' and 'offset'. This patch avoids that the following program triggers the "BUG: MAX_STACK_TRACE_ENTRIES too low!" complaint: #include #include int main() { for (;;) { int fd = open("/dev/infiniband/rdma_cm", O_RDWR); close(fd); } } Suggested-by: Peter Zijlstra Reported-by: Eric Biggers Signed-off-by: Bart Van Assche Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Thomas Gleixner Cc: Waiman Long Cc: Will Deacon Cc: Yuyang Du Link: https://lkml.kernel.org/r/20190722182443.216015-4-bvanassche@acm.org Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index cdb3c2f06092..b8a835fd611b 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -66,10 +66,7 @@ struct lock_class_key { extern struct lock_class_key __lockdep_no_validate__; -struct lock_trace { - unsigned int nr_entries; - unsigned int offset; -}; +struct lock_trace; #define LOCKSTAT_POINTS 4 @@ -105,7 +102,7 @@ struct lock_class { * IRQ/softirq usage tracking bits: */ unsigned long usage_mask; - struct lock_trace usage_traces[XXX_LOCK_USAGE_STATES]; + const struct lock_trace *usage_traces[XXX_LOCK_USAGE_STATES]; /* * Generation counter, when doing certain classes of graph walking, @@ -193,7 +190,7 @@ struct lock_list { struct list_head entry; struct lock_class *class; struct lock_class *links_to; - struct lock_trace trace; + const struct lock_trace *trace; int distance; /* -- cgit v1.2.3 From fce45cd41101f1a9620267146b21f09b3454d8db Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Sun, 28 Jul 2019 21:47:35 -0700 Subject: locking/rwsem: Check for operations on an uninitialized rwsem Currently rwsems is the only locking primitive that lacks this debug feature. Add it under CONFIG_DEBUG_RWSEMS and do the magic checking in the locking fastpath (trylock) operation such that we cover all cases. The unlocking part is pretty straightforward. Signed-off-by: Davidlohr Bueso Signed-off-by: Peter Zijlstra (Intel) Acked-by: Waiman Long Cc: mingo@kernel.org Cc: Davidlohr Bueso Link: https://lkml.kernel.org/r/20190729044735.9632-1-dave@stgolabs.net --- include/linux/rwsem.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux') diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 9d9c663987d8..00d6054687dd 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -45,6 +45,9 @@ struct rw_semaphore { #endif raw_spinlock_t wait_lock; struct list_head wait_list; +#ifdef CONFIG_DEBUG_RWSEMS + void *magic; +#endif #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; #endif @@ -73,6 +76,12 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) # define __RWSEM_DEP_MAP_INIT(lockname) #endif +#ifdef CONFIG_DEBUG_RWSEMS +# define __DEBUG_RWSEM_INITIALIZER(lockname) , .magic = &lockname +#else +# define __DEBUG_RWSEM_INITIALIZER(lockname) +#endif + #ifdef CONFIG_RWSEM_SPIN_ON_OWNER #define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED #else @@ -85,6 +94,7 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) .wait_list = LIST_HEAD_INIT((name).wait_list), \ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock) \ __RWSEM_OPT_INIT(name) \ + __DEBUG_RWSEM_INITIALIZER(name) \ __RWSEM_DEP_MAP_INIT(name) } #define DECLARE_RWSEM(name) \ -- cgit v1.2.3 From 5f35d5a66b3ec62cb5ec4ec2ad9aebe2ac325673 Mon Sep 17 00:00:00 2001 From: Mukesh Ojha Date: Wed, 31 Jul 2019 20:35:03 +0530 Subject: locking/mutex: Make __mutex_owner static to mutex.c __mutex_owner() should only be used by the mutex api's. So, to put this restiction let's move the __mutex_owner() function definition from linux/mutex.h to mutex.c file. There exist functions that uses __mutex_owner() like mutex_is_locked() and mutex_trylock_recursive(), So to keep legacy thing intact move them as well and export them. Move mutex_waiter structure also to keep it private to the file. Signed-off-by: Mukesh Ojha Signed-off-by: Peter Zijlstra (Intel) Cc: mingo@redhat.com Cc: will@kernel.org Link: https://lkml.kernel.org/r/1564585504-3543-1-git-send-email-mojha@codeaurora.org --- include/linux/mutex.h | 38 +++----------------------------------- 1 file changed, 3 insertions(+), 35 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mutex.h b/include/linux/mutex.h index dcd03fee6e01..eb8c62aba263 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -65,29 +65,6 @@ struct mutex { #endif }; -/* - * Internal helper function; C doesn't allow us to hide it :/ - * - * DO NOT USE (outside of mutex code). - */ -static inline struct task_struct *__mutex_owner(struct mutex *lock) -{ - return (struct task_struct *)(atomic_long_read(&lock->owner) & ~0x07); -} - -/* - * This is the control structure for tasks blocked on mutex, - * which resides on the blocked task's kernel stack: - */ -struct mutex_waiter { - struct list_head list; - struct task_struct *task; - struct ww_acquire_ctx *ww_ctx; -#ifdef CONFIG_DEBUG_MUTEXES - void *magic; -#endif -}; - #ifdef CONFIG_DEBUG_MUTEXES #define __DEBUG_MUTEX_INITIALIZER(lockname) \ @@ -144,10 +121,7 @@ extern void __mutex_init(struct mutex *lock, const char *name, * * Returns true if the mutex is locked, false if unlocked. */ -static inline bool mutex_is_locked(struct mutex *lock) -{ - return __mutex_owner(lock) != NULL; -} +extern bool mutex_is_locked(struct mutex *lock); /* * See kernel/locking/mutex.c for detailed documentation of these APIs. @@ -220,13 +194,7 @@ enum mutex_trylock_recursive_enum { * - MUTEX_TRYLOCK_SUCCESS - lock acquired, * - MUTEX_TRYLOCK_RECURSIVE - we already owned the lock. */ -static inline /* __deprecated */ __must_check enum mutex_trylock_recursive_enum -mutex_trylock_recursive(struct mutex *lock) -{ - if (unlikely(__mutex_owner(lock) == current)) - return MUTEX_TRYLOCK_RECURSIVE; - - return mutex_trylock(lock); -} +extern /* __deprecated */ __must_check enum mutex_trylock_recursive_enum +mutex_trylock_recursive(struct mutex *lock); #endif /* __LINUX_MUTEX_H */ -- cgit v1.2.3 From e57d143091f1c0b1a98140a4d2e63e113afb62c0 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 8 Aug 2019 08:47:14 +0200 Subject: mutex: Fix up mutex_waiter usage The patch moving bits into mutex.c was a little too much; by also moving struct mutex_waiter a few less common CONFIGs would no longer build. Fixes: 5f35d5a66b3e ("locking/mutex: Make __mutex_owner static to mutex.c") Signed-off-by: Peter Zijlstra (Intel) --- include/linux/mutex.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mutex.h b/include/linux/mutex.h index eb8c62aba263..aca8f36dfac9 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -65,6 +65,19 @@ struct mutex { #endif }; +/* + * This is the control structure for tasks blocked on mutex, + * which resides on the blocked task's kernel stack: + */ +struct mutex_waiter { + struct list_head list; + struct task_struct *task; + struct ww_acquire_ctx *ww_ctx; +#ifdef CONFIG_DEBUG_MUTEXES + void *magic; +#endif +}; + #ifdef CONFIG_DEBUG_MUTEXES #define __DEBUG_MUTEX_INITIALIZER(lockname) \ -- cgit v1.2.3