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2020-10-01debugobjects: Free per CPU pool after CPU unplugZqiang
If a CPU is offlined the debug objects per CPU pool is not cleaned up. If the CPU is never onlined again then the objects in the pool are wasted. Add a CPU hotplug callback which is invoked after the CPU is dead to free the pool. [ tglx: Massaged changelog and added comment about remote access safety ] Signed-off-by: Zqiang <qiang.zhang@windriver.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Link: https://lore.kernel.org/r/20200908062709.11441-1-qiang.zhang@windriver.com
2020-09-24debugobjects: Allow debug_obj_descr to be constStephen Boyd
The debugobject core could be slightly harder to corrupt if the debug_obj_descr would be a pointer to const memory. Depending on the architecture, const data structures are placed into read-only memory and thus are harder to corrupt or hijack. This descriptor is used to fix up stuff like timers and workqueues when core kernel data structures are busted, so moving the descriptors to read-only memory will make debugobjects more resilient to something going wrong and then corrupting the function pointers inside struct debug_obj_descr. Signed-off-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200815004027.2046113-2-swboyd@chromium.org
2020-07-17debugobjects: Convert to DEFINE_SHOW_ATTRIBUTEQinglang Miao
Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code. [ tglx: Distangled it from the mess in -next ] Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: hch@lst.de Link: https://lkml.kernel.org/r/20200716084747.8034-1-miaoqinglang@huawei.com
2020-01-17debugobjects: Fix various data racesMarco Elver
The counters obj_pool_free, and obj_nr_tofree, and the flag obj_freeing are read locklessly outside the pool_lock critical sections. If read with plain accesses, this would result in data races. This is addressed as follows: * reads outside critical sections become READ_ONCE()s (pairing with WRITE_ONCE()s added); * writes become WRITE_ONCE()s (pairing with READ_ONCE()s added); since writes happen inside critical sections, only the write and not the read of RMWs needs to be atomic, thus WRITE_ONCE(var, var +/- X) is sufficient. The data races were reported by KCSAN: BUG: KCSAN: data-race in __free_object / fill_pool write to 0xffffffff8beb04f8 of 4 bytes by interrupt on cpu 1: __free_object+0x1ee/0x8e0 lib/debugobjects.c:404 __debug_check_no_obj_freed+0x199/0x330 lib/debugobjects.c:969 debug_check_no_obj_freed+0x3c/0x44 lib/debugobjects.c:994 slab_free_hook mm/slub.c:1422 [inline] read to 0xffffffff8beb04f8 of 4 bytes by task 1 on cpu 2: fill_pool+0x3d/0x520 lib/debugobjects.c:135 __debug_object_init+0x3c/0x810 lib/debugobjects.c:536 debug_object_init lib/debugobjects.c:591 [inline] debug_object_activate+0x228/0x320 lib/debugobjects.c:677 debug_rcu_head_queue kernel/rcu/rcu.h:176 [inline] BUG: KCSAN: data-race in __debug_object_init / fill_pool read to 0xffffffff8beb04f8 of 4 bytes by task 10 on cpu 6: fill_pool+0x3d/0x520 lib/debugobjects.c:135 __debug_object_init+0x3c/0x810 lib/debugobjects.c:536 debug_object_init_on_stack+0x39/0x50 lib/debugobjects.c:606 init_timer_on_stack_key kernel/time/timer.c:742 [inline] write to 0xffffffff8beb04f8 of 4 bytes by task 1 on cpu 3: alloc_object lib/debugobjects.c:258 [inline] __debug_object_init+0x717/0x810 lib/debugobjects.c:544 debug_object_init lib/debugobjects.c:591 [inline] debug_object_activate+0x228/0x320 lib/debugobjects.c:677 debug_rcu_head_queue kernel/rcu/rcu.h:176 [inline] BUG: KCSAN: data-race in free_obj_work / free_object read to 0xffffffff9140c190 of 4 bytes by task 10 on cpu 6: free_object+0x4b/0xd0 lib/debugobjects.c:426 debug_object_free+0x190/0x210 lib/debugobjects.c:824 destroy_timer_on_stack kernel/time/timer.c:749 [inline] write to 0xffffffff9140c190 of 4 bytes by task 93 on cpu 1: free_obj_work+0x24f/0x480 lib/debugobjects.c:313 process_one_work+0x454/0x8d0 kernel/workqueue.c:2264 worker_thread+0x9a/0x780 kernel/workqueue.c:2410 Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200116185529.11026-1-elver@google.com
2019-06-14debugobjects: Move printk out of db->lock critical sectionsWaiman Long
The db->lock is a raw spinlock and so the lock hold time is supposed to be short. This will not be the case when printk() is being involved in some of the critical sections. In order to avoid the long hold time, in case some messages need to be printed, the debug_object_is_on_stack() and debug_print_object() calls are now moved out of those critical sections. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org> Cc: Qian Cai <cai@gmx.us> Cc: Zhong Jiang <zhongjiang@huawei.com> Link: https://lkml.kernel.org/r/20190520141450.7575-6-longman@redhat.com
2019-06-14debugobjects: Less aggressive freeing of excess debug objectsWaiman Long
After a system bootup and 3 parallel kernel builds, a partial output of the debug objects stats file was: pool_free :5101 pool_pcp_free :4181 pool_min_free :220 pool_used :104172 pool_max_used :171920 on_free_list :0 objs_allocated:39268280 objs_freed :39160031 More than 39 millions debug objects had since been allocated and then freed. The pool_max_used, however, was only about 172k. So this is a lot of extra overhead in freeing and allocating objects from slabs. It may also causes the slabs to be more fragmented and harder to reclaim. Make the freeing of excess debug objects less aggressive by freeing them at a maximum frequency of 10Hz and about 1k objects at each round of freeing. With that change applied, the partial output of the debug objects stats file after similar actions became: pool_free :5901 pool_pcp_free :3742 pool_min_free :1022 pool_used :104805 pool_max_used :168081 on_free_list :0 objs_allocated:5796864 objs_freed :5687182 Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org> Cc: Qian Cai <cai@gmx.us> Cc: Zhong Jiang <zhongjiang@huawei.com> Link: https://lkml.kernel.org/r/20190520141450.7575-5-longman@redhat.com
2019-06-14debugobjects: Reduce number of pool_lock acquisitions in fill_pool()Waiman Long
In fill_pool(), the pool_lock is acquired and then released once per debug object. If many objects are to be filled, the constant lock and unlock operations are extra overhead. To reduce the overhead, batch them up and do an allocation of 4 objects per lock/unlock sequence. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org> Cc: Qian Cai <cai@gmx.us> Cc: Zhong Jiang <zhongjiang@huawei.com> Link: https://lkml.kernel.org/r/20190520141450.7575-4-longman@redhat.com
2019-06-14debugobjects: Percpu pool lookahead freeing/allocationWaiman Long
Most workloads will allocate a bunch of memory objects, work on them and then freeing all or most of them. So just having a percpu free pool may not reduce the pool_lock contention significantly if large number of objects are being used. To help those situations, we are now doing lookahead allocation and freeing of the debug objects into and out of the percpu free pool. This will hopefully reduce the number of times the pool_lock needs to be taken and hence its contention level. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org> Cc: Qian Cai <cai@gmx.us> Cc: Zhong Jiang <zhongjiang@huawei.com> Link: https://lkml.kernel.org/r/20190520141450.7575-3-longman@redhat.com
2019-06-14debugobjects: Add percpu free poolsWaiman Long
When a multi-threaded workload does a lot of small memory object allocations and deallocations, it may cause the allocation and freeing of many debug objects. This will make the global pool_lock a bottleneck in the performance of the workload. Since interrupts are disabled when acquiring the pool_lock, it may even cause hard lockups to happen. To reduce contention of the global pool_lock, add a percpu debug object free pool that can be used to buffer some of the debug object allocation and freeing requests without acquiring the pool_lock. Each CPU will now have a percpu free pool that can hold up to a maximum of 64 debug objects. Allocation and freeing requests will go to the percpu free pool first. If that fails, the pool_lock will be taken and the global free pool will be used. The presence or absence of obj_cache is used as a marker to see if the percpu cache should be used. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org> Cc: Qian Cai <cai@gmx.us> Cc: Zhong Jiang <zhongjiang@huawei.com> Link: https://lkml.kernel.org/r/20190520141450.7575-2-longman@redhat.com
2019-06-14debugobjects: No need to check return value of debugfs_create()Greg Kroah-Hartman
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Qian Cai <cai@gmx.us> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Waiman Long <longman@redhat.com> Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org> Cc: Zhong Jiang <zhongjiang@huawei.com> Link: https://lkml.kernel.org/r/20190612153513.GA21082@kroah.com
2018-12-28debugobjects: call debug_objects_mem_init earilerQian Cai
The current value of the early boot static pool size, 1024 is not big enough for systems with large number of CPUs with timer or/and workqueue objects selected. As the results, systems have 60+ CPUs with both timer and workqueue objects enabled could trigger "ODEBUG: Out of memory. ODEBUG disabled". Some debug objects are allocated during the early boot. Enabling some options like timers or workqueue objects may increase the size required significantly with large number of CPUs. For example, CONFIG_DEBUG_OBJECTS_TIMERS: No. CPUs x 2 (worker pool) objects: start_kernel workqueue_init_early init_worker_pool init_timer_key debug_object_init plus No. CPUs objects (CONFIG_HIGH_RES_TIMERS): sched_init hrtick_rq_init hrtimer_init CONFIG_DEBUG_OBJECTS_WORK: No. CPUs objects: vmalloc_init __init_work plus No. CPUs x 6 (workqueue) objects: workqueue_init_early alloc_workqueue __alloc_workqueue_key alloc_and_link_pwqs init_pwq Also, plus No. CPUs objects: perf_event_init __init_srcu_struct init_srcu_struct_fields init_srcu_struct_nodes __init_work However, none of the things are actually used or required before debug_objects_mem_init() is invoked, so just move the call right before vmalloc_init(). According to tglx, "the reason why the call is at this place in start_kernel() is historical. It's because back in the days when debugobjects were added the memory allocator was enabled way later than today." Link: http://lkml.kernel.org/r/20181126102407.1836-1-cai@gmx.us Signed-off-by: Qian Cai <cai@gmx.us> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-30debugobjects: avoid recursive calls with kmemleakQian Cai
CONFIG_DEBUG_OBJECTS_RCU_HEAD does not play well with kmemleak due to recursive calls. fill_pool kmemleak_ignore make_black_object put_object __call_rcu (kernel/rcu/tree.c) debug_rcu_head_queue debug_object_activate debug_object_init fill_pool kmemleak_ignore make_black_object ... So add SLAB_NOLEAKTRACE to kmem_cache_create() to not register newly allocated debug objects at all. Link: http://lkml.kernel.org/r/20181126165343.2339-1-cai@gmx.us Signed-off-by: Qian Cai <cai@gmx.us> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Waiman Long <longman@redhat.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-02debugobjects: Remove redundant NULL pointer checkZhong Jiang
kmem_cache_destroy() has a built in NULL pointer check, so the one at the call can be removed. Signed-off-by: Zhong Jiang <zhongjiang@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: <longman@redhat.com> Cc: <arnd@arndb.de> Cc: <yang.shi@linux.alibaba.com> Link: https://lkml.kernel.org/r/1533054298-35824-1-git-send-email-zhongjiang@huawei.com
2018-07-30debugobjects: Make stack check warning more informativeJoel Fernandes (Google)
While debugging an issue debugobject tracking warned about an annotation issue of an object on stack. It turned out that the issue was due to the object in concern being on a different stack which was due to another issue. Thomas suggested to print the pointers and the location of the stack for the currently running task. This helped to figure out that the object was on the wrong stack. As this is general useful information for debugging similar issues, make the error message more informative by printing the pointers. [ tglx: Massaged changelog ] Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Waiman Long <longman@redhat.com> Acked-by: Yang Shi <yang.shi@linux.alibaba.com> Cc: kernel-team@android.com Cc: Arnd Bergmann <arnd@arndb.de> Cc: astrachan@google.com Link: https://lkml.kernel.org/r/20180723212531.202328-1-joel@joelfernandes.org
2018-03-14debugobjects: Avoid another unused variable warningArnd Bergmann
debug_objects_maxchecked is only updated in __debug_check_no_obj_freed(), and only read in debug_objects_maxchecked, unfortunately both of these are optional and depend on different Kconfig symbols. When both CONFIG_DEBUG_OBJECTS_FREE and CONFIG_DEBUG_FS are disabled this warning is emitted: lib/debugobjects.c:56:14: error: 'debug_objects_maxchecked' defined but not used [-Werror=unused-variable] Rather than trying to add more complex #ifdef protections, mark the variable as __maybe_unused so it can be silently dropped when usused. Fixes: bd9dcd046509 ("debugobjects: Export max loops counter") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Yang Shi <yang.shi@linux.alibaba.com> Cc: Waiman Long <longman@redhat.com> Link: https://lkml.kernel.org/r/20180313131857.158876-1-arnd@arndb.de
2018-02-22debugobjects: Fix debug_objects_freed accountingArnd Bergmann
The removal of the batched object freeing has caused the debug_objects_freed to become read-only, and the reading is inside an ifdef, so gcc warns that it is completely unused without CONFIG_DEBUG_FS: lib/debugobjects.c:71:14: error: 'debug_objects_freed' defined but not used [-Werror=unused-variable] Assuming we are still interested in this number, this adds back code to keep track of the freed objects. Fixes: 636e1970fd7d ("debugobjects: Use global free list in free_object()") Suggested-by: Waiman Long <longman@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Waiman Long <longman@redhat.com> Link: https://lkml.kernel.org/r/20180222155335.1647466-1-arnd@arndb.de
2018-02-13debugobjects: Use global free list in __debug_check_no_obj_freed()Yang Shi
__debug_check_no_obj_freed() iterates over the to be freed memory region in chunks and iterates over the corresponding hash bucket list for each chunk. This can accumulate to hundred thousands of checked objects. In the worst case this can trigger the soft lockup detector: NMI watchdog: BUG: soft lockup - CPU#15 stuck for 22s! CPU: 15 PID: 110342 Comm: stress-ng-getde Call Trace: [<ffffffff8141177e>] debug_check_no_obj_freed+0x13e/0x220 [<ffffffff811f8751>] __free_pages_ok+0x1f1/0x5c0 [<ffffffff811fa785>] __free_pages+0x25/0x40 [<ffffffff812638db>] __free_slab+0x19b/0x270 [<ffffffff812639e9>] discard_slab+0x39/0x50 [<ffffffff812679f7>] __slab_free+0x207/0x270 [<ffffffff81269966>] ___cache_free+0xa6/0xb0 [<ffffffff8126c267>] qlist_free_all+0x47/0x80 [<ffffffff8126c5a9>] quarantine_reduce+0x159/0x190 [<ffffffff8126b3bf>] kasan_kmalloc+0xaf/0xc0 [<ffffffff8126b8a2>] kasan_slab_alloc+0x12/0x20 [<ffffffff81265e8a>] kmem_cache_alloc+0xfa/0x360 [<ffffffff812abc8f>] ? getname_flags+0x4f/0x1f0 [<ffffffff812abc8f>] getname_flags+0x4f/0x1f0 [<ffffffff812abe42>] getname+0x12/0x20 [<ffffffff81298da9>] do_sys_open+0xf9/0x210 [<ffffffff81298ede>] SyS_open+0x1e/0x20 [<ffffffff817d6e01>] entry_SYSCALL_64_fastpath+0x1f/0xc2 The code path might be called in either atomic or non-atomic context, but in_atomic() can't tell if the current context is atomic or not on a PREEMPT=n kernel, so cond_resched() can't be used to prevent the softlockup. Utilize the global free list to shorten the loop execution time. [ tglx: Massaged changelog ] Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: longman@redhat.com Link: https://lkml.kernel.org/r/1517872708-24207-5-git-send-email-yang.shi@linux.alibaba.com
2018-02-13debugobjects: Use global free list in free_object()Yang Shi
The newly added global free list allows to avoid lengthy pool_list iterations in free_obj_work() by putting objects either into the pool list when the fill level of the pool is below the maximum or by putting them on the global free list immediately. As the pool is now guaranteed to never exceed the maximum fill level this allows to remove the batch removal from pool list in free_obj_work(). Split free_object() into two parts, so the actual queueing function can be reused without invoking schedule_work() on every invocation. [ tglx: Remove the batch removal from pool list and massage changelog ] Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: longman@redhat.com Link: https://lkml.kernel.org/r/1517872708-24207-4-git-send-email-yang.shi@linux.alibaba.com
2018-02-13debugobjects: Add global free list and the counterYang Shi
free_object() adds objects to the pool list and schedules work when the pool list is larger than the pool size. The worker handles the actual kfree() of the object by iterating the pool list until the pool size is below the maximum pool size again. To iterate the pool list, pool_lock has to be held and the objects which should be freed() need to be put into temporary storage so pool_lock can be dropped for the actual kmem_cache_free() invocation. That's a pointless and expensive exercise if there is a large number of objects to free. In such a case its better to evaulate the fill level of the pool in free_objects() and queue the object to free either in the pool list or if it's full on a separate global free list. The worker can then do the following simpler operation: - Move objects back from the global free list to the pool list if the pool list is not longer full. - Remove the remaining objects in a single list move operation from the global free list and do the kmem_cache_free() operation lockless from the temporary list head. In fill_pool() the global free list is checked as well to avoid real allocations from the kmem cache. Add the necessary list head and a counter for the number of objects on the global free list and export that counter via sysfs: max_chain :79 max_loops :8147 warnings :0 fixups :0 pool_free :1697 pool_min_free :346 pool_used :15356 pool_max_used :23933 on_free_list :39 objs_allocated:32617 objs_freed :16588 Nothing queues objects on the global free list yet. This happens in a follow up change. [ tglx: Simplified implementation and massaged changelog ] Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: longman@redhat.com Link: https://lkml.kernel.org/r/1517872708-24207-3-git-send-email-yang.shi@linux.alibaba.com
2018-02-13debugobjects: Export max loops counterYang Shi
__debug_check_no_obj_freed() can be an expensive operation depending on the size of memory freed. It already exports the maximum chain walk length via debugfs, but this only records the maximum of a single memory chunk. Though there is no information about the total number of objects inspected for a __debug_check_no_obj_freed() operation, which might be significantly larger when a huge memory region is freed. Aggregate the number of objects inspected for a single invocation of __debug_check_no_obj_freed() and export it via sysfs. The resulting output of /sys/kernel/debug/debug_objects/stats looks like: max_chain :121 max_checked :543267 warnings :0 fixups :0 pool_free :1764 pool_min_free :341 pool_used :86438 pool_max_used :268887 objs_allocated:6068254 objs_freed :5981076 [ tglx: Renamed the variable to max_checked and adjusted changelog ] Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: longman@redhat.com Link: https://lkml.kernel.org/r/1517872708-24207-2-git-send-email-yang.shi@linux.alibaba.com
2017-08-14debugobjects: Make kmemleak ignore debug objectsWaiman Long
The allocated debug objects are either on the free list or in the hashed bucket lists. So they won't get lost. However if both debug objects and kmemleak are enabled and kmemleak scanning is done while some of the debug objects are transitioning from one list to the others, false negative reporting of memory leaks may happen for those objects. For example, [38687.275678] kmemleak: 12 new suspected memory leaks (see /sys/kernel/debug/kmemleak) unreferenced object 0xffff92e98aabeb68 (size 40): comm "ksmtuned", pid 4344, jiffies 4298403600 (age 906.430s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 d0 bc db 92 e9 92 ff ff ................ 01 00 00 00 00 00 00 00 38 36 8a 61 e9 92 ff ff ........86.a.... backtrace: [<ffffffff8fa5378a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff8f47c019>] kmem_cache_alloc+0xe9/0x320 [<ffffffff8f62ed96>] __debug_object_init+0x3e6/0x400 [<ffffffff8f62ef01>] debug_object_activate+0x131/0x210 [<ffffffff8f330d9f>] __call_rcu+0x3f/0x400 [<ffffffff8f33117d>] call_rcu_sched+0x1d/0x20 [<ffffffff8f4a183c>] put_object+0x2c/0x40 [<ffffffff8f4a188c>] __delete_object+0x3c/0x50 [<ffffffff8f4a18bd>] delete_object_full+0x1d/0x20 [<ffffffff8fa535c2>] kmemleak_free+0x32/0x80 [<ffffffff8f47af07>] kmem_cache_free+0x77/0x350 [<ffffffff8f453912>] unlink_anon_vmas+0x82/0x1e0 [<ffffffff8f440341>] free_pgtables+0xa1/0x110 [<ffffffff8f44af91>] exit_mmap+0xc1/0x170 [<ffffffff8f29db60>] mmput+0x80/0x150 [<ffffffff8f2a7609>] do_exit+0x2a9/0xd20 The references in the debug objects may also hide a real memory leak. As there is no point in having kmemleak to track debug object allocations, kmemleak checking is now disabled for debug objects. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1502718733-8527-1-git-send-email-longman@redhat.com
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar
<linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-10debugobjects: Improve variable namingWaiman Long
As suggested by Ingo, the debug_objects_alloc counter is now renamed to debug_objects_allocated with minor twist in comment and debug output. Signed-off-by: Waiman Long <longman@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1486503630-1501-1-git-send-email-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-05debugobjects: Reduce contention on the global pool_lockWaiman Long
On a large SMP system with many CPUs, the global pool_lock may become a performance bottleneck as all the CPUs that need to allocate or free debug objects have to take the lock. That can sometimes cause soft lockups like: NMI watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [rcuos/1:21] ... RIP: 0010:[<ffffffff817c216b>] [<ffffffff817c216b>] _raw_spin_unlock_irqrestore+0x3b/0x60 ... Call Trace: [<ffffffff813f40d1>] free_object+0x81/0xb0 [<ffffffff813f4f33>] debug_check_no_obj_freed+0x193/0x220 [<ffffffff81101a59>] ? trace_hardirqs_on_caller+0xf9/0x1c0 [<ffffffff81284996>] ? file_free_rcu+0x36/0x60 [<ffffffff81251712>] kmem_cache_free+0xd2/0x380 [<ffffffff81284960>] ? fput+0x90/0x90 [<ffffffff81284996>] file_free_rcu+0x36/0x60 [<ffffffff81124c23>] rcu_nocb_kthread+0x1b3/0x550 [<ffffffff81124b71>] ? rcu_nocb_kthread+0x101/0x550 [<ffffffff81124a70>] ? sync_exp_work_done.constprop.63+0x50/0x50 [<ffffffff810c59d1>] kthread+0x101/0x120 [<ffffffff81101a59>] ? trace_hardirqs_on_caller+0xf9/0x1c0 [<ffffffff817c2d32>] ret_from_fork+0x22/0x50 To reduce the amount of contention on the pool_lock, the actual kmem_cache_free() of the debug objects will be delayed if the pool_lock is busy. This will temporarily increase the amount of free objects available at the free pool when the system is busy. As a result, the number of kmem_cache allocation and freeing is reduced. To further reduce the lock operations free debug objects in batches of four. Signed-off-by: Waiman Long <longman@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: "Du Changbin" <changbin.du@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jan Stancek <jstancek@redhat.com> Link: http://lkml.kernel.org/r/1483647425-4135-4-git-send-email-longman@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-02-04debugobjects: Scale thresholds with # of CPUsWaiman Long
On a large SMP systems with hundreds of CPUs, the current thresholds for allocating and freeing debug objects (256 and 1024 respectively) may not work well. This can cause a lot of needless calls to kmem_aloc() and kmem_free() on those systems. To alleviate this thrashing problem, the object freeing threshold is now increased to "1024 + # of CPUs * 32". Whereas the object allocation threshold is increased to "256 + # of CPUs * 4". That should make the debug objects subsystem scale better with the number of CPUs available in the system. Signed-off-by: Waiman Long <longman@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: "Du Changbin" <changbin.du@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jan Stancek <jstancek@redhat.com> Link: http://lkml.kernel.org/r/1483647425-4135-3-git-send-email-longman@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-02-04debugobjects: Track number of kmem_cache_alloc/kmem_cache_free doneWaiman Long
New debugfs stat counters are added to track the numbers of kmem_cache_alloc() and kmem_cache_free() function calls to get a sense of how the internal debug objects cache management is performing. Signed-off-by: Waiman Long <longman@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: "Du Changbin" <changbin.du@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jan Stancek <jstancek@redhat.com> Link: http://lkml.kernel.org/r/1483647425-4135-2-git-send-email-longman@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-13Merge branch 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds
Pull workqueue updates from Tejun Heo: "Mostly patches to initialize workqueue subsystem earlier and get rid of keventd_up(). The patches were headed for the last merge cycle but got delayed due to a bug found late minute, which is fixed now. Also, to help debugging, destroy_workqueue() is more chatty now on a sanity check failure." * 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: move wq_numa_init() to workqueue_init() workqueue: remove keventd_up() debugobj, workqueue: remove keventd_up() usage slab, workqueue: remove keventd_up() usage power, workqueue: remove keventd_up() usage tty, workqueue: remove keventd_up() usage mce, workqueue: remove keventd_up() usage workqueue: make workqueue available early during boot workqueue: dump workqueue state on sanity check failures in destroy_workqueue()
2016-11-30lib/debugobjects: export for use in modulesChris Wilson
Drivers, or other modules, that use a mixture of objects (especially objects embedded within other objects) would like to take advantage of the debugobjects facilities to help catch misuse. Currently, the debugobjects interface is only available to builtin drivers and requires a set of EXPORT_SYMBOL_GPL for use by modules. I am using the debugobjects in i915.ko to try and catch some invalid operations on embedded objects. The problem currently only presents itself across module unload so forcing i915 to be builtin is not an option. Link: http://lkml.kernel.org/r/20161122143039.6433-1-chris@chris-wilson.co.uk Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: "Du, Changbin" <changbin.du@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-17debugobj, workqueue: remove keventd_up() usageTejun Heo
Now that workqueue can handle work item queueing from very early during boot, there is no need to gate schedule_work() while !keventd_up(). Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org>
2016-05-19debugobjects: insulate non-fixup logic related to static obj from fixup ↵Du, Changbin
callbacks When activating a static object we need make sure that the object is tracked in the object tracker. If it is a non-static object then the activation is illegal. In previous implementation, each subsystem need take care of this in their fixup callbacks. Actually we can put it into debugobjects core. Thus we can save duplicated code, and have *pure* fixup callbacks. To achieve this, a new callback "is_static_object" is introduced to let the type specific code decide whether a object is static or not. If yes, we take it into object tracker, otherwise give warning and invoke fixup callback. This change has paassed debugobjects selftest, and I also do some test with all debugobjects supports enabled. At last, I have a concern about the fixups that can it change the object which is in incorrect state on fixup? Because the 'addr' may not point to any valid object if a non-static object is not tracked. Then Change such object can overwrite someone's memory and cause unexpected behaviour. For example, the timer_fixup_activate bind timer to function stub_timer. Link: http://lkml.kernel.org/r/1462576157-14539-1-git-send-email-changbin.du@intel.com [changbin.du@intel.com: improve code comments where invoke the new is_static_object callback] Link: http://lkml.kernel.org/r/1462777431-8171-1-git-send-email-changbin.du@intel.com Signed-off-by: Du, Changbin <changbin.du@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Triplett <josh@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tejun Heo <tj@kernel.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19debugobjects: correct the usage of fixup call resultsDu, Changbin
If debug_object_fixup() return non-zero when problem has been fixed. But the code got it backwards, it taks 0 as fixup successfully. So fix it. Signed-off-by: Du, Changbin <changbin.du@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Triplett <josh@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tejun Heo <tj@kernel.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19debugobjects: make fixup functions return bool instead of intDu, Changbin
I am going to introduce debugobjects infrastructure to USB subsystem. But before this, I found the code of debugobjects could be improved. This patchset will make fixup functions return bool type instead of int. Because fixup only need report success or no. boolean is the 'real' type. This patch (of 7): The object debugging infrastructure core provides some fixup callbacks for the subsystem who use it. These callbacks are called from the debug code whenever a problem in debug_object_init is detected. And debugobjects core suppose them returns 1 when the fixup was successful, otherwise 0. So the return type is boolean. A bad thing is that debug_object_fixup use the return value for arithmetic operation. It confused me that what is the reall return type. Reading over the whole code, I found some place do use the return value incorrectly(see next patch). So why use bool type instead? Signed-off-by: Du, Changbin <changbin.du@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Triplett <josh@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tejun Heo <tj@kernel.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-27debugobjects: Allow bigger number of early boot objectsChristian Borntraeger
On my bigger s390 systems I always get "Out of memory. ODEBUG disabled". Since the number of objects is needed at compile time, we can not change the size dynamically before the caches etc are available. Doubling the size seems to do the trick. Since it is init data it will be freed anyway, this should be ok. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Link: http://lkml.kernel.org/r/1453905478-13409-1-git-send-email-borntraeger@de.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-06-04lib/debugobjects.c: convert printk(KERN_DEBUG to pr_debugFabian Frederick
Direct conversion of one KERN_DEBUG message without DEBUG definition (suggested by Josh Triplett) That message will now be disabled by default. (see Documentation/CodingStyle Chapter 13) Signed-off-by: Fabian Frederick <fabf@skynet.be> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04lib/debugobjects.c: add pr_fmt to loggingFabian Frederick
Add ODEBUG: prefix to pr_fmt Signed-off-by: Fabian Frederick <fabf@skynet.be> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04lib/debugobjects.c: convert printk to pr_foo()Fabian Frederick
Convert all printk to pr_foo() except KERN_DEBUG (see Documentation/CodingStyle Chapter 13) Signed-off-by: Fabian Frederick <fabf@skynet.be> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13lib/debugobjects.c: remove unnecessary work pending testXie XiuQi
Remove unnecessary work pending test before calling schedule_work(). It has been tested in queue_work_on() already. No functional changed. Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Reviewed-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-08-18debugobjects: Make debug_object_activate() return statusPaul E. McKenney
In order to better respond to things like duplicate invocations of call_rcu(), RCU needs to see the status of a call to debug_object_activate(). This would allow RCU to leak the callback in order to avoid adding freelist-reuse mischief to the duplicate invoations. This commit therefore makes debug_object_activate() return status, zero for success and -EINVAL for failure. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Sedat Dilek <sedat.dilek@gmail.com> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-02-27hlist: drop the node parameter from iteratorsSasha Levin
I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-18debugobjects: Fill_pool() returns void nowDan Carpenter
There was a return missed in 1fda107d44 "debugobjects: Remove unused return value from fill_pool()". It makes gcc complain: lib/debugobjects.c: In function ‘fill_pool’: lib/debugobjects.c:98:4: warning: ‘return’ with a value, in function returning void [enabled by default] Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Link: http://lkml.kernel.org/r/20120418112810.GA2669@elgon.mountain Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-11debugobjects: printk with irqs enabledThomas Gleixner
No point in keeping interrupts disabled here. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-11debugobjects: Remove unused return value from fill_pool()Thomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-05debugobjects: Fix selftest for static warningsStephen Boyd
debugobjects is now printing a warning when a fixup for a NOTAVAILABLE object is run. This causes the selftest to fail like: ODEBUG: selftest warnings failed 4 != 5 We could just increase the number of warnings that the selftest is expecting to see because that is actually what has changed. But, it turns out that fixup_activate() was written with inverted logic and thus a fixup for a static object returned 1 indicating the object had been fixed, and 0 otherwise. Fix the logic to be correct and update the counts to reflect that nothing needed fixing for a static object. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-23debugobjects: Extend to assert that an object is initializedChristine Chan
Calling del_timer_sync() on an uninitialized timer leads to a never ending loop in lock_timer_base() that spins checking for a non-NULL timer base. Add an assertion to debugobjects to catch usage of uninitialized objects so that we can initialize timers in the del_timer_sync() path before it calls lock_timer_base(). [ sboyd@codeaurora.org: Clarify commit message ] Signed-off-by: Christine Chan <cschan@codeaurora.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1320724108-20788-3-git-send-email-sboyd@codeaurora.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-11-23debugobjects: Be smarter about static objectsStephen Boyd
Make debugobjects use the return code from the fixup function. That allows us better diagnostics in the activate check than relying on a WARN_ON() in the object specific code. [ tglx@linutronix.de: Split out the debugobjects vs. the timer change ] Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Christine Chan <cschan@codeaurora.org> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1320724108-20788-2-git-send-email-sboyd@codeaurora.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-06-20debugobjects: Fix boot crash when kmemleak and debugobjects enabledMarcin Slusarz
Order of initialization look like this: ... debugobjects kmemleak ...(lots of other subsystems)... workqueues (through early initcall) ... debugobjects use schedule_work for batch freeing of its data and kmemleak heavily use debugobjects, so when it comes to freeing and workqueues were not initialized yet, kernel crashes: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff810854d1>] __queue_work+0x29/0x41a [<ffffffff81085910>] queue_work_on+0x16/0x1d [<ffffffff81085abc>] queue_work+0x29/0x55 [<ffffffff81085afb>] schedule_work+0x13/0x15 [<ffffffff81242de1>] free_object+0x90/0x95 [<ffffffff81242f6d>] debug_check_no_obj_freed+0x187/0x1d3 [<ffffffff814b6504>] ? _raw_spin_unlock_irqrestore+0x30/0x4d [<ffffffff8110bd14>] ? free_object_rcu+0x68/0x6d [<ffffffff8110890c>] kmem_cache_free+0x64/0x12c [<ffffffff8110bd14>] free_object_rcu+0x68/0x6d [<ffffffff810b58bc>] __rcu_process_callbacks+0x1b6/0x2d9 ... because system_wq is NULL. Fix it by checking if workqueues susbystem was initialized before using. Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: stable@kernel.org Link: http://lkml.kernel.org/r/20110528112342.GA3068@joi.lan Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-08debugobjects: Add hint for better object identificationStanislaw Gruszka
In complex subsystems like mac80211 structures can contain several timers and work structs, so identifying a specific instance from the call trace and object type output of debugobjects can be hard. Allow the subsystems which support debugobjects to provide a hint function. This function returns a pointer to a kernel address (preferrably the objects callback function) which is printed along with the debugobjects type. Add hint methods for timer_list, work_struct and hrtimer. [ tglx: Massaged changelog, made it compile ] Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> LKML-Reference: <20110307085809.GA9334@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-18Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits) rcu: remove all rcu head initializations, except on_stack initializations rcu head introduce rcu head init on stack Debugobjects transition check rcu: fix build bug in RCU_FAST_NO_HZ builds rcu: RCU_FAST_NO_HZ must check RCU dyntick state rcu: make SRCU usable in modules rcu: improve the RCU CPU-stall warning documentation rcu: reduce the number of spurious RCU_SOFTIRQ invocations rcu: permit discontiguous cpu_possible_mask CPU numbering rcu: improve RCU CPU stall-warning messages rcu: print boot-time console messages if RCU configs out of ordinary rcu: disable CPU stall warnings upon panic rcu: enable CPU_STALL_VERBOSE by default rcu: slim down rcutiny by removing rcu_scheduler_active and friends rcu: refactor RCU's context-switch handling rcu: rename rcutiny rcu_ctrlblk to rcu_sched_ctrlblk rcu: shrink rcutiny by making synchronize_rcu_bh() be inline rcu: fix now-bogus rcu_scheduler_active comments. rcu: Fix bogus CONFIG_PROVE_LOCKING in comments to reflect reality. rcu: ignore offline CPUs in last non-dyntick-idle CPU check ...
2010-05-18Merge branch 'core-debugobjects-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: debugobjects: Section mismatch cleanup
2010-05-10Debugobjects transition checkMathieu Desnoyers
Implement a basic state machine checker in the debugobjects. This state machine checker detects races and inconsistencies within the "active" life of a debugobject. The checker only keeps track of the current state; all the state machine logic is kept at the object instance level. The checker works by adding a supplementary "unsigned int astate" field to the debug_obj structure. It keeps track of the current "active state" of the object. The only constraints that are imposed on the states by the debugobjects system is that: - activation of an object sets the current active state to 0, - deactivation of an object expects the current active state to be 0. For the rest of the states, the state mapping is determined by the specific object instance. Therefore, the logic keeping track of the state machine is within the specialized instance, without any need to know about it at the debugobject level. The current object active state is changed by calling: debug_object_active_state(addr, descr, expect, next) where "expect" is the expected state and "next" is the next state to move to if the expected state is found. A warning is generated if the expected is not found. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: David S. Miller <davem@davemloft.net> CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> CC: akpm@linux-foundation.org CC: mingo@elte.hu CC: laijs@cn.fujitsu.com CC: dipankar@in.ibm.com CC: josh@joshtriplett.org CC: dvhltc@us.ibm.com CC: niv@us.ibm.com CC: peterz@infradead.org CC: rostedt@goodmis.org CC: Valdis.Kletnieks@vt.edu CC: dhowells@redhat.com CC: eric.dumazet@gmail.com CC: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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