From 199e371f59d31c828345b0d959d27d752827b517 Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Tue, 23 Apr 2013 12:34:03 -0400 Subject: [PATCH] lockdep: Print out additional debugging advice when we hit lockdep BUGs We occasionally get reports of these BUGs being hit, and the stack trace doesn't necessarily always tell us what we need to know about why we are hitting those limits. If users start attaching /proc/lock_stats to reports we may have more of a clue what's going on. Signed-off-by: Dave Jones Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20130423163403.GA12839@redhat.com Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/lockdep.c b/kernel/lockdep.c index e5deddadeab1..c5d1e6bbdb3e 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -411,6 +411,7 @@ static int save_trace(struct stack_trace *trace) printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); printk("turning off the locking correctness validator.\n"); + printk("Attach output of /proc/lock_stat to bug report\n"); dump_stack(); return 0; @@ -765,6 +766,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); printk("turning off the locking correctness validator.\n"); + printk("Attach output of /proc/lock_stat to bug report\n"); dump_stack(); return NULL; } @@ -836,6 +838,7 @@ static struct lock_list *alloc_list_entry(void) printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); printk("turning off the locking correctness validator.\n"); + printk("Attach output of /proc/lock_stat to bug report\n"); dump_stack(); return NULL; } @@ -2050,6 +2053,7 @@ static inline int lookup_chain_cache(struct task_struct *curr, printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); printk("turning off the locking correctness validator.\n"); + printk("Attach output of /proc/lock_stat to bug report\n"); dump_stack(); return 0; } @@ -3191,6 +3195,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, printk("BUG: MAX_LOCK_DEPTH too low, depth: %i max: %lu!\n", curr->lockdep_depth, MAX_LOCK_DEPTH); printk("turning off the locking correctness validator.\n"); + printk("Attach output of /proc/lock_stat to bug report\n"); lockdep_print_held_locks(current); debug_show_all_locks();