From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754974Ab1J1DhX (ORCPT ); Thu, 27 Oct 2011 23:37:23 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35002 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754369Ab1J1DhW convert rfc822-to-8bit (ORCPT ); Thu, 27 Oct 2011 23:37:22 -0400 Message-ID: <1319773015.6759.30.camel@deadeye> Subject: [PATCH 1/2] lockdep,rtmutex,bug: Show taint flags on error From: Ben Hutchings To: Peter Zijlstra , Ingo Molnar Cc: Nick Bowler , Greg KH , Dave Jones , Rusty Russell , Randy Dunlap , LKML , Debian kernel maintainers Date: Fri, 28 Oct 2011 04:36:55 +0100 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.0.3-2 Mime-Version: 1.0 X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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