From: Nathan Lynch rcu_offline_cpu and rcu_move_batch have been broken since the list_head's in struct rcu_head and struct rcu_data were replaced with singly-linked lists: CC kernel/rcupdate.o kernel/rcupdate.c: In function `rcu_move_batch': kernel/rcupdate.c:222: warning: passing arg 2 of `list_add_tail' from incompatible pointer type kernel/rcupdate.c: In function `rcu_offline_cpu': kernel/rcupdate.c:239: warning: passing arg 1 of `rcu_move_batch' from incompatible pointer type kernel/rcupdate.c:240: warning: passing arg 1 of `rcu_move_batch' from incompatible pointer type kernel/rcupdate.c:236: warning: label `unlock' defined but not used Kernel crashes when you try to offline a cpu, not surprisingly. It also looks like rcu_move_batch isn't preempt-safe so I touched that up, and got rid of an unused label in rcu_offline_cpu. Signed-off-by: Nathan Lynch Signed-off-by: Andrew Morton --- 25-akpm/kernel/rcupdate.c | 21 +++++++++++---------- 1 files changed, 11 insertions(+), 10 deletions(-) diff -puN kernel/rcupdate.c~fixes-for-rcu_offline_cpu-rcu_move_batch-268-rc2 kernel/rcupdate.c --- 25/kernel/rcupdate.c~fixes-for-rcu_offline_cpu-rcu_move_batch-268-rc2 2004-07-26 16:59:32.624172752 -0700 +++ 25-akpm/kernel/rcupdate.c 2004-07-26 16:59:32.627172296 -0700 @@ -210,16 +210,18 @@ static void rcu_check_quiescent_state(vo * locking requirements, the list it's pulling from has to belong to a cpu * which is dead and hence not processing interrupts. */ -static void rcu_move_batch(struct list_head *list) +static void rcu_move_batch(struct rcu_head *list) { - struct list_head *entry; - int cpu = smp_processor_id(); + int cpu; local_irq_disable(); - while (!list_empty(list)) { - entry = list->next; - list_del(entry); - list_add_tail(entry, &RCU_nxtlist(cpu)); + + cpu = smp_processor_id(); + + while (list != NULL) { + *RCU_nxttail(cpu) = list; + RCU_nxttail(cpu) = &list->next; + list = list->next; } local_irq_enable(); } @@ -233,11 +235,10 @@ static void rcu_offline_cpu(int cpu) spin_lock_bh(&rcu_state.mutex); if (rcu_ctrlblk.cur != rcu_ctrlblk.completed) cpu_quiet(cpu); -unlock: spin_unlock_bh(&rcu_state.mutex); - rcu_move_batch(&RCU_curlist(cpu)); - rcu_move_batch(&RCU_nxtlist(cpu)); + rcu_move_batch(RCU_curlist(cpu)); + rcu_move_batch(RCU_nxtlist(cpu)); tasklet_kill_immediate(&RCU_tasklet(cpu), cpu); } _