Date: Fri, 12 Dec 2008 12:06:28 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/kern kern_prot.c kern_sysctl.c Message-ID: <200812121206.mBCC6g0r021827@repoman.freebsd.org>
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kib 2008-12-12 12:06:28 UTC
FreeBSD src repository
Modified files:
sys/kern kern_prot.c kern_sysctl.c
Log:
SVN rev 185983 on 2008-12-12 12:06:28Z by kib
The userland_sysctl() function retries sysctl_root() until returned
error is not EAGAIN. Several sysctls that inspect another process use
p_candebug() for checking access right for the curproc. p_candebug()
returns EAGAIN for some reasons, in particular, for the process doing
exec() now. If execing process tries to lock Giant, we get a livelock,
because sysctl handlers are covered by Giant, and often do not sleep.
Break the livelock by dropping Giant and allowing other threads to
execute in the EAGAIN loop.
Also, do not return EAGAIN from p_candebug() when process is executing,
use more appropriate EBUSY error [1].
Reported and tested by: pho
Suggested by: rwatson [1]
Reviewed by: rwatson, des
MFC after: 1 week
Revision Changes Path
1.215 +1 -1 src/sys/kern/kern_prot.c
1.181 +8 -2 src/sys/kern/kern_sysctl.c
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