Messages in this thread | | | Date | Fri, 16 Jan 2009 10:48:38 -0800 | From | Mike Travis <> | Subject | Re: new (common) WARNING message? |
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Stefan Richter wrote: > Mike Travis wrote: >> I've been seeing these on and off for a while now. They don't >> seem to affect anything but perhaps I should track them down? >> >> Do you know what it means? (I'm asking you because evidently >> debugobjects.c is from you? I read the good explanation in the >> changelog of 3ac7fe5a, but it didn't clue me into what's going >> on. ;-) >> >> Thanks, >> Mike >> -- >> >> [ 1294.973592] ODEBUG: object is on stack, but not annotated >> [ 1294.974067] ------------[ cut here ]------------ >> [ 1294.974067] WARNING: at /mdata/lwork/polaris3/travis/workareas/ingo-latest/linux-2.6-for-ingo/lib/debugobjects.c:253 __debug_object_init+0x27c/0x2f0() >> [ 1294.974067] Hardware name: X7DBT >> [ 1294.974067] Pid: 4150, comm: offline-test Tainted: G W 2.6.29-rc1-4k-defconfig.01151634-00255-gc99dbbe-dirty #89 >> [ 1294.974067] Call Trace: >> [ 1294.974067] [<ffffffff81047e3f>] warn_slowpath+0xd3/0xf2 >> [ 1294.974067] [<ffffffff8106c64f>] ? trace_hardirqs_off+0xd/0xf >> [ 1294.974067] [<ffffffff815ca6ac>] ? _spin_unlock_irqrestore+0x3d/0x4c >> [ 1294.974067] [<ffffffff8125bebe>] ? __debug_check_no_obj_freed+0xf6/0x14c >> [ 1294.974067] [<ffffffff81048d3c>] ? printk+0x6c/0x6e >> [ 1294.974067] [<ffffffff8125c449>] ? __debug_object_init+0xf9/0x2f0 >> [ 1294.974067] [<ffffffff8125b3ae>] ? _raw_spin_unlock+0xc7/0xf6 >> [ 1294.974067] [<ffffffff8125c5cc>] __debug_object_init+0x27c/0x2f0 >> [ 1294.974067] [<ffffffff8125c66d>] debug_object_init+0x14/0x17 >> [ 1294.974067] [<ffffffff81052320>] init_timer+0x1d/0x2a >> [ 1294.974067] [<ffffffff81025077>] hpet_cpuhp_notify+0xad/0x124 >> [ 1294.974067] [<ffffffff81025233>] ? hpet_work+0x0/0x21a >> [ 1294.974067] [<ffffffff81062057>] notifier_call_chain+0x33/0x5b >> [ 1294.974067] [<ffffffff810620ad>] __raw_notifier_call_chain+0xe/0x10 >> [ 1294.974067] [<ffffffff810620c3>] raw_notifier_call_chain+0x14/0x16 >> [ 1294.974067] [<ffffffff815c5190>] _cpu_up+0x115/0x155 >> [ 1294.974067] [<ffffffff815c527c>] cpu_up+0x65/0x73 >> [ 1294.974067] [<ffffffff815ac21d>] store_online+0x52/0x7b >> [ 1294.974067] [<ffffffff812ff775>] sysdev_store+0x20/0x22 >> [ 1294.974067] [<ffffffff81134f6b>] sysfs_write_file+0xe9/0x11e >> [ 1294.974067] [<ffffffff810e0da5>] vfs_write+0xea/0x148 >> [ 1294.974067] [<ffffffff810e0ec7>] sys_write+0x4c/0x72 >> [ 1294.974067] [<ffffffff8100c6cb>] system_call_fastpath+0x16/0x1b >> [ 1294.974067] ---[ end trace 4eaa2a86a8e2da24 ]--- >> -- > > The warning tells us that arch/x86/kernel/hpet.c::hpet_cpuhp_notify() > allocates a timer on the stack. In particular, it allocates a struct > hpet_work_struct on the stack which incorporates a timer. > > Now, a timer instance on a stack would be wrong if the function which > defined that timer exits too early. But in case of hpet_cpuhp_notify(), > this is OK since > - it waits for the work be done, > - the work does not rearm itself. > IOW the work and thus the timer won't be accessed anymore when > hpet_cpuhp_notify() returns. > > So, hpet_cpuhp_notify() apparently needs a variant of INIT_DELAYED_WORK > which uses init_timer_on_stack instead of init_timer, to say "trust me, > I know what I'm doing".
Hi Stefan,
Thanks for the great explanation!
Cheers, Mike
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