On Thu, 17 Jun 2010 09:29:50 +0300 Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> wrote: > Fix > > BUG: using smp_processor_id() in preemptible [00000000] code: > s2disk/3392 caller is nr_iowait_cpu+0xe/0x1e > Pid: 3392, comm: s2disk Not tainted 2.6.35-rc3-dbg-00106-ga75e02b #2 > Call Trace: > [<c1184c55>] debug_smp_processor_id+0xa5/0xbc > [<c10282a5>] nr_iowait_cpu+0xe/0x1e > [<c104ab7c>] update_ts_time_stats+0x32/0x6c > [<c104ac73>] get_cpu_idle_time_us+0x36/0x58 > [<c124229b>] get_cpu_idle_time+0x12/0x74 > [<c1242963>] cpufreq_governor_dbs+0xc3/0x2dc > [<c1240437>] __cpufreq_governor+0x51/0x85 > [<c1241190>] __cpufreq_set_policy+0x10c/0x13d > [<c12413d3>] cpufreq_add_dev_interface+0x212/0x233 > [<c1241b1e>] ? handle_update+0x0/0xd > [<c1241a18>] cpufreq_add_dev+0x34b/0x35a > [<c103c973>] ? schedule_delayed_work_on+0x11/0x13 > [<c12c14db>] cpufreq_cpu_callback+0x59/0x63 > [<c1042f39>] notifier_call_chain+0x26/0x48 > [<c1042f7d>] __raw_notifier_call_chain+0xe/0x10 > [<c102efb9>] __cpu_notify+0x15/0x29 > [<c102efda>] cpu_notify+0xd/0xf > [<c12bfb30>] _cpu_up+0xaf/0xd2 > [<c12b3ad4>] enable_nonboot_cpus+0x3d/0x94 > [<c1055eef>] hibernation_snapshot+0x104/0x1a2 > [<c1058b49>] snapshot_ioctl+0x24b/0x53e > [<c1028ad1>] ? sub_preempt_count+0x7c/0x89 > [<c10ab91d>] vfs_ioctl+0x2e/0x8c > [<c10588fe>] ? snapshot_ioctl+0x0/0x53e > [<c10ac2c7>] do_vfs_ioctl+0x42f/0x45a > [<c10a0ba5>] ? fsnotify_modify+0x4f/0x5a > [<c11e9dc3>] ? tty_write+0x0/0x1d0 > [<c10a12d6>] ? vfs_write+0xa2/0xda > [<c10ac333>] sys_ioctl+0x41/0x62 > [<c10027d3>] sysenter_do_call+0x12/0x2d > > The initial fix was to use get_cpu/put_cpu in nr_iowait_cpu. However, > Arjan stated that "the bug is that it needs to be nr_iowait_cpu(int > cpu)". > > This patch introduces nr_iowait_cpu(int cpu) and changes to its > callers. > > Arjan also pointed out that we can't use get_cpu/put_cpu in > update_ts_time_stats since we "pick the current cpu, rather than the > one denoted by ts" in that case. To match given *ts and cpu denoted > by *ts we use new field in the struct tick_sched: int cpu. > > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> Acked-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
