Messages in this thread Patch in this message | | | From | "zhaoyang.huang" <> | Subject | [RFC PATCH] kernel/locking: introduce stack_handle for tracing the callstack | Date | Fri, 20 Jan 2023 16:48:22 +0800 |
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From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
When deadlock happens, sometimes it is hard to know how the owner get the lock especially the owner is running when snapshot(ramdump). Introduce stack_handle to record the trace.
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com> --- include/linux/rwsem.h | 9 ++++++++- kernel/locking/rwsem.c | 18 ++++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index efa5c32..ad4c591 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -16,6 +16,11 @@ #include <linux/atomic.h> #include <linux/err.h> +#define CONFIG_TRACE_RWSEMS +#ifdef CONFIG_TRACE_RWSEMS +typedef u32 depot_stack_handle_t; +#endif + #ifdef CONFIG_DEBUG_LOCK_ALLOC # define __RWSEM_DEP_MAP_INIT(lockname) \ .dep_map = { \ @@ -31,7 +36,6 @@ #ifdef CONFIG_RWSEM_SPIN_ON_OWNER #include <linux/osq_lock.h> #endif - /* * For an uncontended rwsem, count and owner are the only fields a task * needs to touch when acquiring the rwsem. So they are put next to each @@ -60,6 +64,9 @@ struct rw_semaphore { #ifdef CONFIG_DEBUG_RWSEMS void *magic; #endif +#ifdef CONFIG_TRACE_RWSEMS + depot_stack_handle_t trace_handle; +#endif #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map dep_map; #endif diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 4487359..a12766e 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -28,6 +28,7 @@ #include <linux/rwsem.h> #include <linux/atomic.h> #include <trace/events/lock.h> +#include <linux/stacktrace.h> #ifndef CONFIG_PREEMPT_RT #include "lock_events.h" @@ -74,6 +75,7 @@ list_empty(&(sem)->wait_list) ? "" : "not ")) \ debug_locks_off(); \ } while (0) +#define MAX_TRACE 16 #else # define DEBUG_RWSEMS_WARN_ON(c, sem) #endif @@ -174,6 +176,9 @@ static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem, (atomic_long_read(&sem->owner) & RWSEM_NONSPINNABLE); atomic_long_set(&sem->owner, val); +#ifdef CONFIG_TRACE_RWSEMS + sem->trace_handle = owner ? set_track_prepare() : NULL; +#endif } static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) @@ -397,6 +402,19 @@ enum rwsem_wake_type { return false; } +#ifdef CONFIG_TRACE_RWSEMS +static inline depot_stack_handle_t set_track_prepare(void) +{ + depot_stack_handle_t trace_handle; + unsigned long entries[MAX_TRACE]; + unsigned int nr_entries; + + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3); + trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT); + + return trace_handle; +} +#endif /* * handle the lock release when processes blocked on it that can now run * - if we come here from up_xxxx(), then the RWSEM_FLAG_WAITERS bit must -- 1.9.1
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