Messages in this thread | | | Date | Sun, 27 Sep 2015 18:16:15 +0200 | Subject | Re: [GIT PULL rcu/urgent] Fix two more 4.3 regressions | From | Sedat Dilek <> |
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On Sun, Sep 27, 2015 at 6:02 PM, Sedat Dilek <sedat.dilek@gmail.com> wrote: > On Sun, Sep 27, 2015 at 5:58 PM, Sedat Dilek <sedat.dilek@gmail.com> wrote: >> On Sun, Sep 27, 2015 at 5:55 PM, Sedat Dilek <sedat.dilek@gmail.com> wrote: >>> On Sun, Sep 27, 2015 at 5:49 PM, Paul E. McKenney >>> <paulmck@linux.vnet.ibm.com> wrote: >>>> On Sun, Sep 27, 2015 at 09:37:05AM +0200, Sedat Dilek wrote: >>>>> On Sun, Sep 27, 2015 at 9:32 AM, Paul E. McKenney >>>>> <paulmck@linux.vnet.ibm.com> wrote: >>>>> > On Sun, Sep 27, 2015 at 08:28:39AM +0200, Sedat Dilek wrote: >>>>> >> Hi, >>>>> >> >>>>> >> as I have observed here some lockdep issues (one could be solved in >>>>> >> netdev) I wanted to try this patchset. >>>>> >> >>>>> >> Unfortunately, you cannot pull from... >>>>> >> >>>>> >> "These changes are available in the git repository at: >>>>> >> >>>>> >> git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git for-mingo >>>>> >> >>>>> >> for you to fetch changes up to 19a5ecde086a6a5287978b12ae948fa691b197b7: >>>>> >> >>>>> >> rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex >>>>> >> (2015-09-20 21:01:22 -0700) >>>>> >> >>>>> >> ---------------------------------------------------------------- >>>>> >> Oleg Nesterov (1): >>>>> >> rcu: Change _wait_rcu_gp() to work around GCC bug 67055 >>>>> >> >>>>> >> Paul E. McKenney (1): >>>>> >> rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex >>>>> >> >>>>> >> include/linux/rcupdate.h | 11 +++++------ >>>>> >> kernel/rcu/tree.c | 5 +++++ >>>>> >> 2 files changed, 10 insertions(+), 6 deletions(-)" >>>>> >> >>>>> >> So, I have stolen them from linux-next.git. >>>>> >> >>>>> >> Please look at this, Thanks. >>>>> > >>>>> > Does it work better now? (Forgot to actually push the new name...) >>>>> >>>>> Hi Paul, >>>>> >>>>> now for-mingo Git branch has this two fixes. >>>> >>>> Whew!!! Apologies for the hassle! >>>> >>>>> I just booted into my new kernel with the "stolen" rcu.fixes from -next. >>>>> >>>>> For the lockdep problems I will do a CONFIG_DEBUG_LOCKDEP=y to see if >>>>> I get some more infos on the workqueue trouble. >>>>> >>>>> [ 23.874836] BUG: sleeping function called from invalid context at >>>>> kernel/workqueue.c:2678 >>>>> [ 23.874902] in_atomic(): 0, irqs_disabled(): 1, pid: 1411, name: acpid >>>> >>>> Did you get a stack trace? There are quite a few potential callers of >>>> start_flush_work() via flush_work(). >>>> >>> >>> Hi Paul :-), >>> >>> Here is the stack trace. >>> >>> [ 23.045871] BUG: sleeping function called from invalid context at >>> kernel/workqueue.c:2678 >>> [ 23.045982] in_atomic(): 0, irqs_disabled(): 1, pid: 1399, name: acpid >>> [ 23.046064] 3 locks held by acpid/1399: >>> [ 23.046066] #0: (&evdev->mutex){+.+...}, at: [<ffffffff8174ac7c>] >>> evdev_release+0xbc/0xf0 >>> [ 23.046081] #1: (&dev->mutex#2){+.+...}, at: [<ffffffff81742397>] >>> input_close_device+0x27/0x70 >>> [ 23.046093] #2: (hid_open_mut){+.+...}, at: [<ffffffffa0056388>] >>> usbhid_close+0x28/0xb0 [usbhid] >>> [ 23.046106] irq event stamp: 3306 >>> [ 23.046109] hardirqs last enabled at (3305): [<ffffffff8192ae32>] >>> _raw_spin_unlock_irq+0x32/0x60 >>> [ 23.046115] hardirqs last disabled at (3306): [<ffffffff81121017>] >>> del_timer_sync+0x37/0x110 >>> [ 23.046122] softirqs last enabled at (2704): [<ffffffff818b12c9>] >>> local_bh_enable+0x9/0x20 >>> [ 23.046128] softirqs last disabled at (2702): [<ffffffff818b12a9>] >>> local_bh_disable+0x9/0x20 >>> [ 23.046136] CPU: 2 PID: 1399 Comm: acpid Not tainted >>> 4.3.0-rc3-3-llvmlinux-amd64 #1 >>> [ 23.046139] Hardware name: SAMSUNG ELECTRONICS CO., LTD. >>> 530U3BI/530U4BI/530U4BH/530U3BI/530U4BI/530U4BH, BIOS 13XK 03/28/2013 >>> [ 23.046143] ffff8800d36ee948 0000000000000092 0000000000000000 >>> ffff8800bbacfae8 >>> [ 23.046151] ffffffff8149adad ffff8800bbacfb18 ffffffff810cd1ea >>> ffffffff81c56f0a >>> [ 23.046158] ffff8800c22dc400 0000000000000000 0000000000000a76 >>> ffff8800bbacfb58 >>> [ 23.046165] Call Trace: >>> [ 23.046172] [<ffffffff8149adad>] dump_stack+0x7d/0xa0 >>> [ 23.046177] [<ffffffff810cd1ea>] ___might_sleep+0x28a/0x2a0 >>> [ 23.046182] [<ffffffff810cceef>] __might_sleep+0x4f/0xc0 >>> [ 23.046187] [<ffffffff810afbff>] start_flush_work+0x2f/0x290 >>> [ 23.046192] [<ffffffff810afbac>] flush_work+0x5c/0x80 >>> [ 23.046195] [<ffffffff810afb6a>] ? flush_work+0x1a/0x80 >>> [ 23.046202] [<ffffffff810eed0d>] ? trace_hardirqs_off+0xd/0x10 >>> [ 23.046206] [<ffffffff810aecc8>] ? try_to_grab_pending+0x48/0x360 >>> [ 23.046211] [<ffffffff8192ac53>] ? _raw_spin_lock_irqsave+0x73/0x80 >>> [ 23.046216] [<ffffffff810afff9>] __cancel_work_timer+0x179/0x260 >>> [ 23.046221] [<ffffffff8192add2>] ? _raw_spin_unlock_irqrestore+0x52/0x80 >>> [ 23.046226] [<ffffffff81120fcd>] ? try_to_del_timer_sync+0xad/0xc0 >>> [ 23.046230] [<ffffffff810afe78>] cancel_work_sync+0x18/0x20 >>> [ 23.046237] [<ffffffffa00563d5>] usbhid_close+0x75/0xb0 [usbhid] >>> [ 23.046245] [<ffffffffa00394d1>] hidinput_close+0x31/0x40 [hid] >>> [ 23.046251] [<ffffffffa00394a0>] ? hidinput_open+0x40/0x40 [hid] >>> [ 23.046256] [<ffffffff817423b8>] input_close_device+0x48/0x70 >>> [ 23.046261] [<ffffffff8174ac96>] evdev_release+0xd6/0xf0 >>> [ 23.046267] [<ffffffff812728c7>] __fput+0x107/0x240 >>> [ 23.046271] [<ffffffff81272756>] ____fput+0x16/0x20 >>> [ 23.046276] [<ffffffff810b945c>] task_work_run+0x6c/0xe0 >>> [ 23.046282] [<ffffffff81003aa7>] prepare_exit_to_usermode+0x117/0x120 >>> [ 23.046287] [<ffffffff81003ce1>] syscall_return_slowpath+0x231/0x2a0 >>> [ 23.046292] [<ffffffff8126efa5>] ? filp_close+0x65/0x90 >>> [ 23.046298] [<ffffffff810ef1c9>] ? trace_hardirqs_on_caller+0x19/0x290 >>> [ 23.046303] [<ffffffff81003017>] ? trace_hardirqs_on_thunk+0x17/0x19 >>> [ 23.046308] [<ffffffff8192bb62>] int_ret_from_sys_call+0x25/0x9f >>> >>> Can you give help on how to "debug" this? >>> >>> I switched from full-dynticks to simple cpu-accounting which did not help. >>> But this was only a suspicion as Jiri pointed to the possibility >>> del_timer_sync() could have get some mis-optimization. >>> >>> So, more empty head here. >>> >> >> Forgot to attach dmesg-log and my kernel-config. >> Sorry about that. >> > > Time for a pause! > > Forgot to attach disassembled kernel/workqueue.o. >
When looking at start_flush_work() in kernel/workqueue.c... ...I remembered the comments of Lai Jiangshan concerning the might_sleep() check there.
I tried to move the might_sleep() line to __cancel_work_timer() as requested, but that did not help or narrowed down whatever.
Please see [1] for more details.
- Sedat -
[1] http://marc.info/?l=linux-kernel&m=144184707824750&w=2
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