Messages in this thread |  | | Date | Thu, 24 Aug 2000 23:38:02 +0200 | From | almesber@lrc ... | Subject | Re: [FIX] Make deadlock detection work for file locking |
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BTW, this is a little off-topic, I kind of wonder what the right semantics for deadlock detection are with threads. POSIX 1003.1 1996-07-12 says:
"A potential for deadlock occurs if a process controlling a locked region is put to sleep by attempting to lock the locked region of another process. If the system detects that sleeping until a locked region is unlocked would cause a deadlock, the fcntl() function shall fail with an [EDEADLK] error."
Okay, that's a little vague already. Now let's make it more interesting by adding threads:
Process Thread Action (executed in this order) A 1 grab lock X B 1 grab lock Y A 2 try to get lock Y B 2 try to get lock X
Solaris 2.5.1 thinks this is a deadlock. Linux 2.4.0-test1-ac16 thinks it isn't. I haven't found any definition of what "putting a process to sleep" means in POSIX.1.
Opinions ?
- Werner
-- _________________________________________________________________________ / Werner Almesberger, ICA, EPFL, CH werner.almesberger@ica.epfl.ch / /_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_____________________/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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