On Thu, Sep 01, 2016 at 06:21:30PM +0800, kernel test robot wrote: > > FYI, we noticed the following commit: > > https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git > wb-buf-throttle > commit 8bc4ad9498f81d6689da42457615db0989e720d3 ("writeback: throttle > buffered writeback") > > in testcase: boot > > on test machine: qemu-system-x86_64 -enable-kvm -cpu Westmere -m 512M > > caused below changes: > > > +--------------------------------------+------------+------------+ > | | b2e4e4e34d | 8bc4ad9498 | > +--------------------------------------+------------+------------+ > | boot_successes | 6 | 0 | > | boot_failures | 0 | 8 | > | INFO:suspicious_RCU_usage | 0 | 8 | > | message:INFO:suspicious_RCU_usage | 0 | 0.0 | > | pattern:INFO:suspicious_RCU_usage | 0 | 0 | > | calltrace:disk_events_workfn | 0 | 8 | > | message:calltrace:disk_events_workfn | 0 | 0.0 | > | pattern:calltrace:disk_events_workfn | 0 | 0 | > +--------------------------------------+------------+------------+ > > > > [ 7.389264] stack backtrace: > [ 7.391300] CPU: 0 PID: 19 Comm: kworker/0:1 Not tainted > 4.8.0-rc4-00008-g8bc4ad9 #1 > [ 7.395279] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > Debian-1.8.2-1 04/01/2014 > [ 7.398012] Workqueue: events_freezable_power_ disk_events_workfn > [ 7.399933] 0000000000000000 ffff88003db1f8e8 ffffffff8178ed3b > ffff88003db184c0 > [ 7.404348] 0000000000000001 ffff88003db1f918 ffffffff81123472 > ffff88003db184c0 > [ 7.407158] ffffffff84091180 0000000000000003 ffff880039d4c400 > ffff88003db1f938 > [ 7.410074] Call Trace: > [ 7.411328] [<ffffffff8178ed3b>] dump_stack+0x82/0xb8 > [ 7.413982] [<ffffffff81123472>] lockdep_rcu_suspicious+0xf7/0x100 > [ 7.415828] [<ffffffff817873f4>] bio_blkcg+0x89/0x93 > [ 7.417336] [<ffffffff817891f0>] check_blkcg_changed+0x58/0x1b8
Hmm... can't reproduce here on qemu with v4.8-rc5 and the same kernel config. Can you please check whether it reproduces on v4.8-rc5? If so, is there any way I can get the qemu image and command line used? Thanks. -- tejun
