Messages in this thread | ![/](/images/icornerl.gif) | | Subject | [cgroups] suspicious rcu_dereference_check() usage! | From | Mike Galbraith <> | Date | Mon, 20 Feb 2017 11:15:23 +0100 |
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Running LTP on master.today (v4.10) with a seriously bloated PREEMPT config inspired box to emit the below.
[ 7160.458996] =============================== [ 7160.463195] [ INFO: suspicious RCU usage. ] [ 7160.467387] 4.10.0-default #100 Tainted: G E [ 7160.472808] ------------------------------- [ 7160.476999] ./include/linux/cgroup.h:435 suspicious rcu_dereference_check() usage! [ 7160.484576] [ 7160.484576] other info that might help us debug this: [ 7160.484576] [ 7160.492577] [ 7160.492577] rcu_scheduler_active = 2, debug_locks = 1 [ 7160.499113] 1 lock held by pids_task1/19308: [ 7160.503390] #0: (&cgroup_threadgroup_rwsem){+++++.}, at: [<ffffffff81095b60>] _do_fork+0xf0/0x710 [ 7160.512450] [ 7160.512450] stack backtrace: [ 7160.516810] CPU: 5 PID: 19308 Comm: pids_task1 Tainted: G E 4.10.0-default #100 [ 7160.525239] Hardware name: IBM System x3550 M3 -[7944K3G]-/69Y5698 , BIOS -[D6E150AUS-1.10]- 12/15/2010 [ 7160.534965] Call Trace: [ 7160.537414] dump_stack+0x85/0xc9 [ 7160.540732] lockdep_rcu_suspicious+0xd5/0x110 [ 7160.545177] task_css.constprop.7+0x88/0x90 [ 7160.549357] pids_can_fork+0x132/0x160 [ 7160.553106] cgroup_can_fork+0x63/0xc0 [ 7160.556855] copy_process.part.30+0x17ef/0x21b0 [ 7160.561382] ? _do_fork+0xf0/0x710 [ 7160.564786] ? free_pages_and_swap_cache+0x9e/0xc0 [ 7160.569575] _do_fork+0xf0/0x710 [ 7160.572806] ? __this_cpu_preempt_check+0x13/0x20 [ 7160.577505] ? __percpu_counter_add+0x86/0xb0 [ 7160.581860] ? entry_SYSCALL_64_fastpath+0x5/0xc2 [ 7160.586562] ? do_syscall_64+0x2d/0x200 [ 7160.590395] SyS_clone+0x19/0x20 [ 7160.593623] do_syscall_64+0x6c/0x200 [ 7160.597283] entry_SYSCALL64_slow_path+0x25/0x25 [ 7160.601899] RIP: 0033:0x7fdaa3b881c4 [ 7160.605473] RSP: 002b:00007ffd21635d50 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 [ 7160.613036] RAX: ffffffffffffffda RBX: 0000000000004b6c RCX: 00007fdaa3b881c4 [ 7160.620162] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 [ 7160.627288] RBP: 00007ffd21635d90 R08: 0000000000000000 R09: 00007fdaa4052700 [ 7160.634414] R10: 00007fdaa40529d0 R11: 0000000000000246 R12: 00007ffd21635d50 [ 7160.641539] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
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