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Subject: Re: svn commit: r326758 - in head/sys/i386: conf include
To: Eugene Grosbein <eugen@grosbein.net>,
 Konstantin Belousov <kostikbel@gmail.com>, Conrad Meyer <cem@FreeBSD.org>
References: <201712110432.vBB4WbnE021090@repo.freebsd.org>
 <20171211091943.GF2272@kib.kiev.ua> <5A2E5D44.9030904@grosbein.net>
 <4a9c76c9-8063-9420-b198-14487b089840@FreeBSD.org>
 <5A30378A.3040609@grosbein.net>
Cc: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
From: John Baldwin <jhb@FreeBSD.org>
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Date: Tue, 12 Dec 2017 16:55:56 -0500
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On 12/12/17 3:09 PM, Eugene Grosbein wrote:
> On 13.12.2017 02:32, John Baldwin wrote:
> 
>> Certainly for MIPS I have found that compiling with clang
>> instead of gcc for mips64 gives a kernel that panics for stack overflow for any
>> use of NFS.  It might be that this is due to something MIPS-specific, but it
>> might be worthwhile retesting with kstack_pages=2 and building the kernel
>> with CROSS_TOOLCHAIN=i386-gcc after installing the appropriate package.
> 
> You may want to check NFS code that uses stack heavily.
> Here are numbers for i386 (bytes-on-stack, module, what function):
> 
> 1344 nfs_nfsdport.o <nfssvc_nfsd>:
> 1152 nfs_nfsdserv.o <nfsrvd_lockt>:
> 1128 nfs_nfsdserv.o <nfsrvd_lock>:
> 952 nfs_nfsdserv.o <nfsrvd_rename>:
> 664 nfs_nfsdserv.o <nfsrvd_open>:
> 640 nfs_nfsdserv.o <nfsrvd_link>:
> 624 nfs_nfsdserv.o <nfsrvd_create>:
> 608 nfs_nfsdserv.o <nfsrvd_mknod>:
> 600 nfs_clvfsops.o <nfs_mount>:

My point is that you should compare gcc with clang as 10.x switched to
clang and that may be a factor in the stack overflows beginning with 10.x.

-- 
John Baldwin