Commits
David S. Miller committed ab5c780913b
sparc64: Do irq_{enter,exit}() around generic_smp_call_function*().
Otherwise rcu_irq_{enter,exit}() do not happen and we get dumps like:
====================
[ 188.275021] ===============================
[ 188.309351] [ INFO: suspicious RCU usage. ]
[ 188.343737] 3.18.0-rc3-00068-g20f3963-dirty #54 Not tainted
[ 188.394786] -------------------------------
[ 188.429170] include/linux/rcupdate.h:883 rcu_read_lock() used
illegally while idle!
[ 188.505235]
other info that might help us debug this:
[ 188.554230]
RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
[ 188.637587] RCU used illegally from extended quiescent state!
[ 188.690684] 3 locks held by swapper/7/0:
[ 188.721932] #0: (&x->wait#11){......}, at: [<0000000000495de8>] complete+0x8/0x60
[ 188.797994] #1: (&p->pi_lock){-.-.-.}, at: [<000000000048510c>] try_to_wake_up+0xc/0x400
[ 188.881343] #2: (rcu_read_lock){......}, at: [<000000000048a910>] select_task_rq_fair+0x90/0xb40
[ 188.973043]stack backtrace:
[ 188.993879] CPU: 7 PID: 0 Comm: swapper/7 Not tainted 3.18.0-rc3-00068-g20f3963-dirty #54
[ 189.076187] Call Trace:
[ 189.089719] [0000000000499360] lockdep_rcu_suspicious+0xe0/0x100
[ 189.147035] [000000000048a99c] select_task_rq_fair+0x11c/0xb40
[ 189.202253] [00000000004852d8] try_to_wake_up+0x1d8/0x400
[ 189.252258] [000000000048554c] default_wake_function+0xc/0x20
[ 189.306435] [0000000000495554] __wake_up_common+0x34/0x80
[ 189.356448] [00000000004955b4] __wake_up_locked+0x14/0x40
[ 189.406456] [0000000000495e08] complete+0x28/0x60
[ 189.448142] [0000000000636e28] blk_end_sync_rq+0x8/0x20
[ 189.496057] [0000000000639898] __blk_mq_end_request+0x18/0x60
[ 189.550249] [00000000006ee014] scsi_end_request+0x94/0x180
[ 189.601286] [00000000006ee334] scsi_io_completion+0x1d4/0x600
[ 189.655463] [00000000006e51c4] scsi_finish_command+0xc4/0xe0
[ 189.708598] [00000000006ed958] scsi_softirq_done+0x118/0x140
[ 189.761735] [00000000006398ec] __blk_mq_complete_request_remote+0xc/0x20
[ 189.827383] [00000000004c75d0] generic_smp_call_function_single_interrupt+0x150/0x1c0
[ 189.906581] [000000000043e514] smp_call_function_single_client+0x14/0x40
====================
Based almost entirely upon a patch by Paul E. McKenney.
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>