Please could you ack or nak this?

Ben.

On Fri, Oct 28, 2011 at 04:36:55AM +0100, Ben Hutchings wrote:
> Currently lock debugging is disabled when the kernel is tainted, with
> a few exceptions.  It is already recognised that this can be useful
> for staging modules (TAINT_CRAP), but that also goes for out-of-tree
> modules (TAINT_OOT_MODULE) so long as core kernel developers don't
> have to spend time debugging them.  Also, there are several reasons
> for tainting that are unlikely to introduce false locking bug reports
> (e.g. TAINT_FIRMWARE_WORKAROUND).
> 
> Instead of disabling lock debugging, show the taint flags in all
> lockdep and rtmutex-debug error messages.
> 
> Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
> ---
>  kernel/lockdep.c       |   23 +++++++++++++++--------
>  kernel/panic.c         |   10 ----------
>  kernel/rtmutex-debug.c |    1 +
>  3 files changed, 16 insertions(+), 18 deletions(-)
> 
> diff --git a/kernel/lockdep.c b/kernel/lockdep.c
> index e69434b..b2c4537 100644
> --- a/kernel/lockdep.c
> +++ b/kernel/lockdep.c
> @@ -567,11 +567,12 @@ static void lockdep_print_held_locks(struct task_struct 
> *curr)
>       }
>  }
>  
> -static void print_kernel_version(void)
> +static void print_kernel_ident(void)
>  {
> -     printk("%s %.*s\n", init_utsname()->release,
> +     printk("%s %.*s %s\n", init_utsname()->release,
>               (int)strcspn(init_utsname()->version, " "),
> -             init_utsname()->version);
> +             init_utsname()->version,
> +             print_tainted());
>  }
>  
>  static int very_verbose(struct lock_class *class)
> @@ -1148,7 +1149,7 @@ print_circular_bug_header(struct lock_list *entry, 
> unsigned int depth,
>       printk("\n");
>       printk("======================================================\n");
>       printk("[ INFO: possible circular locking dependency detected ]\n");
> -     print_kernel_version();
> +     print_kernel_ident();
>       printk("-------------------------------------------------------\n");
>       printk("%s/%d is trying to acquire lock:\n",
>               curr->comm, task_pid_nr(curr));
> @@ -1487,7 +1488,7 @@ print_bad_irq_dependency(struct task_struct *curr,
>       printk("======================================================\n");
>       printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
>               irqclass, irqclass);
> -     print_kernel_version();
> +     print_kernel_ident();
>       printk("------------------------------------------------------\n");
>       printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
>               curr->comm, task_pid_nr(curr),
> @@ -1716,7 +1717,7 @@ print_deadlock_bug(struct task_struct *curr, struct 
> held_lock *prev,
>       printk("\n");
>       printk("=============================================\n");
>       printk("[ INFO: possible recursive locking detected ]\n");
> -     print_kernel_version();
> +     print_kernel_ident();
>       printk("---------------------------------------------\n");
>       printk("%s/%d is trying to acquire lock:\n",
>               curr->comm, task_pid_nr(curr));
> @@ -2223,7 +2224,7 @@ print_usage_bug(struct task_struct *curr, struct 
> held_lock *this,
>       printk("\n");
>       printk("=================================\n");
>       printk("[ INFO: inconsistent lock state ]\n");
> -     print_kernel_version();
> +     print_kernel_ident();
>       printk("---------------------------------\n");
>  
>       printk("inconsistent {%s} -> {%s} usage.\n",
> @@ -2288,7 +2289,7 @@ print_irq_inversion_bug(struct task_struct *curr,
>       printk("\n");
>       printk("=========================================================\n");
>       printk("[ INFO: possible irq lock inversion dependency detected ]\n");
> -     print_kernel_version();
> +     print_kernel_ident();
>       printk("---------------------------------------------------------\n");
>       printk("%s/%d just changed the state of lock:\n",
>               curr->comm, task_pid_nr(curr));
> @@ -3169,6 +3170,7 @@ print_unlock_inbalance_bug(struct task_struct *curr, 
> struct lockdep_map *lock,
>       printk("\n");
>       printk("=====================================\n");
>       printk("[ BUG: bad unlock balance detected! ]\n");
> +     print_kernel_ident();
>       printk("-------------------------------------\n");
>       printk("%s/%d is trying to release lock (",
>               curr->comm, task_pid_nr(curr));
> @@ -3613,6 +3615,7 @@ print_lock_contention_bug(struct task_struct *curr, 
> struct lockdep_map *lock,
>       printk("\n");
>       printk("=================================\n");
>       printk("[ BUG: bad contention detected! ]\n");
> +     print_kernel_ident();
>       printk("---------------------------------\n");
>       printk("%s/%d is trying to contend lock (",
>               curr->comm, task_pid_nr(curr));
> @@ -3987,6 +3990,7 @@ print_freed_lock_bug(struct task_struct *curr, const 
> void *mem_from,
>       printk("\n");
>       printk("=========================\n");
>       printk("[ BUG: held lock freed! ]\n");
> +     print_kernel_ident();
>       printk("-------------------------\n");
>       printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
>               curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
> @@ -4044,6 +4048,7 @@ static void print_held_locks_bug(struct task_struct 
> *curr)
>       printk("\n");
>       printk("=====================================\n");
>       printk("[ BUG: lock held at task exit time! ]\n");
> +     print_kernel_ident();
>       printk("-------------------------------------\n");
>       printk("%s/%d is exiting with locks still held!\n",
>               curr->comm, task_pid_nr(curr));
> @@ -4141,6 +4146,7 @@ void lockdep_sys_exit(void)
>               printk("\n");
>               printk("================================================\n");
>               printk("[ BUG: lock held when returning to user space! ]\n");
> +             print_kernel_ident();
>               printk("------------------------------------------------\n");
>               printk("%s/%d is leaving the kernel with locks still held!\n",
>                               curr->comm, curr->pid);
> @@ -4160,6 +4166,7 @@ void lockdep_rcu_suspicious(const char *file, const int 
> line, const char *s)
>       printk("\n");
>       printk("===============================\n");
>       printk("[ INFO: suspicious RCU usage. ]\n");
> +     print_kernel_ident();
>       printk("-------------------------------\n");
>       printk("%s:%d %s!\n", file, line, s);
>       printk("\nother info that might help us debug this:\n\n");
> diff --git a/kernel/panic.c b/kernel/panic.c
> index b2659360..ad03fb5 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -233,16 +233,6 @@ unsigned long get_taint(void)
>  
>  void add_taint(unsigned flag)
>  {
> -     /*
> -      * Can't trust the integrity of the kernel anymore.
> -      * We don't call directly debug_locks_off() because the issue
> -      * is not necessarily serious enough to set oops_in_progress to 1
> -      * Also we want to keep up lockdep for staging development and
> -      * post-warning case.
> -      */
> -     if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
> -             printk(KERN_WARNING "Disabling lock debugging due to kernel 
> taint\n");
> -
>       set_bit(flag, &tainted_mask);
>  }
>  EXPORT_SYMBOL(add_taint);
> diff --git a/kernel/rtmutex-debug.c b/kernel/rtmutex-debug.c
> index a2e7e72..077257f 100644
> --- a/kernel/rtmutex-debug.c
> +++ b/kernel/rtmutex-debug.c
> @@ -101,6 +101,7 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter 
> *waiter)
>  
>       printk("\n============================================\n");
>       printk(  "[ BUG: circular locking deadlock detected! ]\n");
> +     printk("%s\n", print_tainted());
>       printk(  "--------------------------------------------\n");
>       printk("%s/%d is deadlocking current task %s/%d\n\n",
>              task->comm, task_pid_nr(task),
> -- 
> 1.7.7
> 
> 
> 

-- 
Ben Hutchings
We get into the habit of living before acquiring the habit of thinking.
                                                              - Albert Camus


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