Messages in this thread | | | Date | Wed, 19 Jan 2005 17:01:23 -0500 (EST) | From | linux-os <> | Subject | Re: 2.6.10-mm1 hang |
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On Wed, 19 Jan 2005, Andrew Morton wrote:
> Badari Pulavarty <pbadari@us.ibm.com> wrote: >> >> I was playing with kexec+kdump and ran into this on 2.6.10-mm1. >> I have seen similar behaviour on 2.6.10. >> >> I am using a 4-way P-III machine. I have a module which tries >> gets same spinlock twice. When I try to "insmod" this module, >> my system hangs. All my windows froze, no more new logins, >> console froze, doesn't respond to sysrq. I wasn't expecting >> a system hang. Why ? Ideas ? >> > > Maybe all the other CPUs are stuck trying to send an IPI to this one? An > NMI watchdog trace would tell. > >> #include <linux/init.h> >> #include <asm/uaccess.h> >> #include <linux/spinlock.h> >> spinlock_t mylock = SPIN_LOCK_UNLOCKED; >> static int __init panic_init(void) >> { >> spin_lock_irq(&mylock); >> spin_lock_irq(&mylock); >> return 1; >> } > -
What would you expect this to do? After the first lock is obtained, the second MUST fail forever or else the spin-lock doesn't work. The code, above, just proves that spin-locks work!
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