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Date:      Thu, 09 Mar 2017 10:43:14 +0100
From:      Alexandre Martins <alexandre.martins@stormshield.eu>
To:        freebsd-current <freebsd-current@freebsd.org>
Subject:   smp_rendezvous_action: Are atomics correctly used ?
Message-ID:  <2092905.6A8RAGlt18@pc-alex>

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Hello,

I'm curently reading the code of the function smp_rendezvous_action, in=
=20
kern/subr_smp.c file. In that function, i see that the variable smp_rv_=
waiters=20
is read in some while() loop in a non-atomic way.

https://svnweb.freebsd.org/base/head/sys/kern/subr_smp.c?view=3Dannotat=
e#l412
https://svnweb.freebsd.org/base/head/sys/kern/subr_smp.c?view=3Dannotat=
e#l458
https://svnweb.freebsd.org/base/head/sys/kern/subr_smp.c?view=3Dannotat=
e#l472

I suspect one of my freeze to be due by that.

Should this function be patched to use=20
"atomic_load_acq_int(&smp_rv_waiters[])" ?

Best regards

=2D-=20
Alexandre Martins
STORMSHIELD


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