Re: [PATCH] x86,nmi: Fix section mismatch warnings on 32-bit
From: Don Zickus
Date: Wed Jun 06 2012 - 14:28:47 EST
On Wed, Jun 06, 2012 at 05:45:50PM +0200, Ingo Molnar wrote:
>
> btw., to hijack a NMI watchdog thread, I'm sometimes getting
> these:
Sure. :-)
>
> initcall flow_cache_init_global+0x0/0x17a returned 0 after 346 usecs
> calling pg_init+0x0/0x31b @ 1
> pktgen: Packet Generator for packet performance testing. Version: 2.74
> hub 2-0:1.0: state 7 ports 10 chg 0000 evt 0000
> ------------[ cut here ]------------
> WARNING: at kernel/watchdog.c:242 watchdog_overflow_callback+0xa4/0xd0()
> Watchdog detected hard LOCKUP on cpu 1Pid: 93, comm: kworker/u:1 Not tainted 3.5.0-rc1-01411-gb2f5ce5-dirty #188912
> Call Trace:
> <NMI> [<ffffffff810ada34>] ? watchdog_overflow_callback+0xa4/0xd0
> [<ffffffff8104a09b>] warn_slowpath_common+0x6b/0x90
> [<ffffffff8104a126>] warn_slowpath_fmt+0x46/0x50
> [<ffffffff810ad990>] ? proc_dohung_task_timeout_secs+0x40/0x40
> [<ffffffff810ada34>] watchdog_overflow_callback+0xa4/0xd0
> [<ffffffff810e0bb8>] __perf_event_overflow+0x158/0x240
> [<ffffffff810de220>] ? perf_event_task_disable+0x90/0x90
> [<ffffffff810e1624>] perf_event_overflow+0x14/0x20
> [<ffffffff810142a3>] x86_pmu_handle_irq+0xe3/0x130
> [<ffffffff81012749>] perf_event_nmi_handler+0x19/0x20
> [<ffffffff81006539>] nmi_handle.isra.1+0x89/0xd0
> [<ffffffff810064b0>] ? die+0x80/0x80
> [<ffffffff81006b51>] do_nmi+0x331/0x350
> [<ffffffff81ca7c62>] end_repeat_nmi+0x1a/0x1e
> [<ffffffff8102250c>] ? early_serial_putc+0x2c/0x50
> [<ffffffff8102250c>] ? early_serial_putc+0x2c/0x50
> [<ffffffff8102250c>] ? early_serial_putc+0x2c/0x50
> <<EOE>> [<ffffffff8102256c>] early_serial_write+0x3c/0x50
> [<ffffffff8104b8b7>] console_unlock+0x267/0x360
> [<ffffffff8104bf13>] vprintk_emit+0x533/0x540
> [<ffffffff81c8dab3>] printk+0x4d/0x4f
> [<ffffffff81794bf0>] ? ata_port_probe+0x40/0x40
> [<ffffffff810751f9>] async_run_entry_fn+0x99/0x160
> [<ffffffff81065621>] process_one_work+0x2c1/0x550
> [<ffffffff81065570>] ? process_one_work+0x210/0x550
> [<ffffffff81097eee>] ? put_lock_stats.isra.16+0xe/0x40
> [<ffffffff81075160>] ? __async_schedule+0x180/0x180
> [<ffffffff81065d3a>] worker_thread+0x18a/0x290
> [<ffffffff81065bb0>] ? rescuer_thread+0x2c0/0x2c0
> [<ffffffff8106c002>] kthread+0xb2/0xc0
> [<ffffffff81ca9154>] kernel_thread_helper+0x4/0x10
> [<ffffffff8106bf50>] ? kthread_flush_work_fn+0x20/0x20
> [<ffffffff81ca9150>] ? gs_change+0xb/0xb
> ---[ end trace 34a2acc48c10e4d7 ]---
> initcall pg_init+0x0/0x31b returned 0 after 49580351 usecs
49 seconds eh? Sounds like a candidate.
> calling init_net_drop_monitor+0x0/0x164 @ 1
> drop_monitor: Initializing network drop monitor service
> initcall init_net_drop_monitor+0x0/0x164 returned 0 after 96956 usecs
> ata1.00: ATA-6: HDS722525VLAT80, V36OA60A, max UDMA/100
> calling llc_init+0x0/0x20 @ 1
>
> Which I suspect is the pg_init() in net/core/pktgen.c.
>
> So it does its performance testing with all irqs disabled?
It seems worker_thread disables irqs, so maybe the pkt generator is
ignorant of it. But it seems like this should have always been a problem.
I am not sure how that code is supposed to work, but I suspect the person
who wrote the test did not expect it to run for 49 seconds?
Ingo, how many cpus do you have on your machine?
Cheers,
Don
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