Date: Wed, 7 Aug 2019 16:37:57 +0800 From: Erich Dollansky <freebsd.ed.lists@sumeritec.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Daniel Eischen <deischen@freebsd.org>, freebsd-questions@freebsd.org, freebsd-threads@freebsd.org Subject: Re: mutex held in a thread which is cancelled stays busy Message-ID: <20190807163757.2b5d52fa.freebsd.ed.lists@sumeritec.com> In-Reply-To: <20190807071002.GF2731@kib.kiev.ua> References: <20190806165429.14bc4052.freebsd.ed.lists@sumeritec.com> <1FC05CEB-982F-484F-9E41-5A74FF564494@freebsd.org> <20190807071002.GF2731@kib.kiev.ua>
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Hi, On Wed, 7 Aug 2019 10:10:02 +0300 Konstantin Belousov <kostikbel@gmail.com> wrote: > On Tue, Aug 06, 2019 at 08:58:30PM -0400, Daniel Eischen wrote: > > > > > On Aug 6, 2019, at 4:54 AM, Erich Dollansky > > > <freebsd.ed.lists@sumeritec.com> wrote: > > > > > > Hi, > > > > > > for testing purpose, I did the following. > > > > > > Start a thread, initialise a mutex in a global variable, lock the > > > mutex and wait in that thread. > > > > > > Wait in the main program until above's thread waits and cancel it. > > > > > > Clean up behind the cancelled thread but leave intentional the > > > mutex locked. > > > > > > I would have expected now to get an error like 'EOWNERDEAD' doing > > > operations with that mutex. But I get 'EBUSY' as the error. > > > > Are you initializing the mutex as a robust mutex, via > > pthread_mutexattr_setrobust()? Are you using _lock() or > > _trylock()? > Robust mutexes only have special properties on the process > termination. They behave same as the normal mutexes if the owning > thread is terminated. > man says: [EOWNERDEAD] The argument mutex points to a robust mutex and the previous owning thread terminated while holding the mutex lock. Erich
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