Messages in this thread | | | Date | Tue, 8 May 2007 16:40:47 +0400 | From | Oleg Nesterov <> | Subject | Re: 2.6.21-mm1 hwsusp: BUG at workqueue.c:106 |
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On 05/08, Jarek Poplawski wrote: > > On 08-05-2007 12:55, Oleg Nesterov wrote: > > On 05/08, Andrew Morton wrote: > >> On Tue, 08 May 2007 10:57:35 +0200 Jiri Slaby <jirislaby@gmail.com> wrote: > >> > >>> this occured in dmesg during resuming from hwsusp in 2.6.21-mm1 (captured > >>> through netconsole). Perfectly reproducible, it simply happens each time I > >>> try it. > >> Let's cc Oleg. > >> > >>> usb_endpoint usbdev5.1_ep00: PM: resume from 0, parent usb5 still 2 > >>> ------------[ cut here ]------------ > >>> kernel BUG at /home/l/latest/xxx/kernel/workqueue.c:106! > >>> invalid opcode: 0000 [#1] > >>> SMP > >>> Modules linked in: ipv6 floppy ohci1394 ieee1394 parport_pc parport usbhid > >>> ehci_hcd pata_acpi ff_memless sr_mod cdrom > ... > > queue_delayed_work(). > > > > Probably, cancel_delayed_work(&delayed_work->work) was called with the ->timer > > pending. This is wrong, cancel_delayed_work() clears _PENDING unconditionally, > > Maybe I miss your point, but clearing is conditional: on timer delete... > > I think more suspicious is calling cancel_work_sync() for a delayed work > (with timer pending). Or maybe some race profits from _PENDING cleared > without locking?
Yes, of course, I meant cancel_work_sync(), sorry for the confusion.
Thanks!
So, once again, cancel_work_sync(&dwork->work) is wrong unless the timer was stopped.
Before make-cancel_rearming_delayed_work-reliable.patch
it requires that the @work can't be re-queued.
After works, but waits for the timer expiration in a busy-wait loop.
Oleg.
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