diff options
| -rw-r--r-- | include/linux/lockdep.h | 20 | ||||
| -rw-r--r-- | include/linux/sched.h | 3 | ||||
| -rw-r--r-- | kernel/locking/lockdep.c | 52 |
3 files changed, 70 insertions, 5 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index e1e0fcd99613..c75eedd55af5 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -284,6 +284,26 @@ struct held_lock { */ struct hist_lock { /* + * Id for each entry in the ring buffer. This is used to + * decide whether the ring buffer was overwritten or not. + * + * For example, + * + * |<----------- hist_lock ring buffer size ------->| + * pppppppppppppppppppppiiiiiiiiiiiiiiiiiiiiiiiiiiiii + * wrapped > iiiiiiiiiiiiiiiiiiiiiiiiiii....................... + * + * where 'p' represents an acquisition in process + * context, 'i' represents an acquisition in irq + * context. + * + * In this example, the ring buffer was overwritten by + * acquisitions in irq context, that should be detected on + * rollback or commit. + */ + unsigned int hist_id; + + /* * Seperate stack_trace data. This will be used at commit step. */ struct stack_trace trace; diff --git a/include/linux/sched.h b/include/linux/sched.h index 5235fba537fc..772c5f643764 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -854,6 +854,9 @@ struct task_struct { unsigned int xhlock_idx; /* For restoring at history boundaries */ unsigned int xhlock_idx_hist[XHLOCK_CTX_NR]; + unsigned int hist_id; + /* For overwrite check at each context exit */ + unsigned int hist_id_save[XHLOCK_CTX_NR]; #endif #ifdef CONFIG_UBSAN diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 56f69cc53ddc..eda8114ef793 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4681,6 +4681,17 @@ EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); static atomic_t cross_gen_id; /* Can be wrapped */ /* + * Make an entry of the ring buffer invalid. + */ +static inline void invalidate_xhlock(struct hist_lock *xhlock) +{ + /* + * Normally, xhlock->hlock.instance must be !NULL. + */ + xhlock->hlock.instance = NULL; +} + +/* * Lock history stacks; we have 3 nested lock history stacks: * * Hard IRQ @@ -4712,14 +4723,28 @@ static atomic_t cross_gen_id; /* Can be wrapped */ */ void crossrelease_hist_start(enum xhlock_context_t c) { - if (current->xhlocks) - current->xhlock_idx_hist[c] = current->xhlock_idx; + struct task_struct *cur = current; + + if (cur->xhlocks) { + cur->xhlock_idx_hist[c] = cur->xhlock_idx; + cur->hist_id_save[c] = cur->hist_id; + } } void crossrelease_hist_end(enum xhlock_context_t c) { - if (current->xhlocks) - current->xhlock_idx = current->xhlock_idx_hist[c]; + struct task_struct *cur = current; + + if (cur->xhlocks) { + unsigned int idx = cur->xhlock_idx_hist[c]; + struct hist_lock *h = &xhlock(idx); + + cur->xhlock_idx = idx; + + /* Check if the ring was overwritten. */ + if (h->hist_id != cur->hist_id_save[c]) + invalidate_xhlock(h); + } } static int cross_lock(struct lockdep_map *lock) @@ -4765,6 +4790,7 @@ static inline int depend_after(struct held_lock *hlock) * Check if the xhlock is valid, which would be false if, * * 1. Has not used after initializaion yet. + * 2. Got invalidated. * * Remind hist_lock is implemented as a ring buffer. */ @@ -4796,6 +4822,7 @@ static void add_xhlock(struct held_lock *hlock) /* Initialize hist_lock's members */ xhlock->hlock = *hlock; + xhlock->hist_id = current->hist_id++; xhlock->trace.nr_entries = 0; xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES; @@ -4934,6 +4961,7 @@ static int commit_xhlock(struct cross_lock *xlock, struct hist_lock *xhlock) static void commit_xhlocks(struct cross_lock *xlock) { unsigned int cur = current->xhlock_idx; + unsigned int prev_hist_id = xhlock(cur).hist_id; unsigned int i; if (!graph_lock()) @@ -4952,6 +4980,17 @@ static void commit_xhlocks(struct cross_lock *xlock) break; /* + * Filter out the cases that the ring buffer was + * overwritten and the previous entry has a bigger + * hist_id than the following one, which is impossible + * otherwise. + */ + if (unlikely(before(xhlock->hist_id, prev_hist_id))) + break; + + prev_hist_id = xhlock->hist_id; + + /* * commit_xhlock() returns 0 with graph_lock already * released if fail. */ @@ -5024,9 +5063,12 @@ void lockdep_init_task(struct task_struct *task) int i; task->xhlock_idx = UINT_MAX; + task->hist_id = 0; - for (i = 0; i < XHLOCK_CTX_NR; i++) + for (i = 0; i < XHLOCK_CTX_NR; i++) { task->xhlock_idx_hist[i] = UINT_MAX; + task->hist_id_save[i] = 0; + } task->xhlocks = kzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR, GFP_KERNEL); |