[lkml]   [2004]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] fixes for rcu_offline_cpu, rcu_move_batch (2.6.8-rc2)

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.

This fixes the crash for me; does it look ok?

Signed-off-by: Nathan Lynch <>

diff -prauNX /home/nathanl/working/dontdiff 2.6.8-rc2/kernel/rcupdate.c 2.6.8-rc2-ntl/kernel/rcupdate.c
--- 2.6.8-rc2/kernel/rcupdate.c 2004-07-23 19:58:35.000000000 -0500
+++ 2.6.8-rc2-ntl/kernel/rcupdate.c 2004-07-26 13:41:15.000000000 -0500
@@ -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;

- 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;
@@ -233,11 +235,10 @@ static void rcu_offline_cpu(int cpu)
if (rcu_ctrlblk.cur != rcu_ctrlblk.completed)

- 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);

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 14:04    [W:0.066 / U:0.256 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site