Messages in this thread | | | Date | Thu, 17 Mar 2011 15:27:29 +0100 | Subject | Re: um: WARNING: at kernel/futex.c:786 __unqueue_futex | From | richard -rw- weinberger <> |
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On Thu, Mar 17, 2011 at 3:08 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > On Thu, 2011-03-17 at 13:25 +0100, richard -rw- weinberger wrote: >> Lai, >> >> Your commit 2e12978a >> (futex,plist: Pass the real head of the priority list to plist_del()) >> triggers gazillions warnings on User Mode Linux (x86, Linus' tree as of today): >> >> ------------[ cut here ]------------ >> WARNING: at kernel/futex.c:786 __unqueue_futex+0x12/0x16() >> Modules linked in: >> 27d4cce8: [<081c13fe>] dump_stack+0x1c/0x20 >> 27d4cd00: [<08071aa0>] warn_slowpath_common+0x49/0x5f >> 27d4cd18: [<08071acb>] warn_slowpath_null+0x15/0x19 >> 27d4cd28: [<0808fdb8>] __unqueue_futex+0x12/0x16 >> 27d4cd38: [<0808fef3>] futex_wait+0x137/0x1ed >> 27d4cdd0: [<080910c3>] do_futex+0x78/0x7c4 >> 27d4cedc: [<080918e6>] sys_futex+0xd7/0xed >> 27d4cf28: [<0805abf6>] handle_syscall+0x7a/0x98 >> 27d4cf78: [<080685d9>] userspace+0x2c9/0x370 >> 27d4cfe0: [<08058be5>] fork_handler+0x53/0x5b >> 27d4cffc: [<00000000>] 0x0 >> >> ---[ end trace ed7709f235f82328 ]--- >> >> !spin_is_locked(q->lock_ptr) in the WARN_ON() at line 786 >> triggers the warnings. > > Crap, I bet you are running CONFIG_SMP=n. I'll test this. We may need to > make that a WARN_ON_SMP().
BTW: When using WARN_ON_SMP() the if-statement in __unqueue_futex will not longer work.
WARN_ON_SMP() is defined as "do { } while (0)" on non CONFIG_SMP systems.
> -- Steve > >> >> I'm not sure whether this shows a bug within UML >> or the WARN_ON() is wrong. >> >> What do you think? >> > > >
-- Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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