Date: Mon, 3 Oct 2005 13:06:29 -0400 From: John Baldwin <jhb@FreeBSD.org> To: Roman Kurakin <rik@cronyx.ru> Cc: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net>, freebsd-current@FreeBSD.org, FreeBSD current mailing list <current@FreeBSD.org> Subject: Re: LOR: kern_descrip.c:2277,2278 Message-ID: <200510031306.31314.jhb@FreeBSD.org> In-Reply-To: <4340E785.3030705@cronyx.ru> References: <Pine.BSF.4.53.0501172204330.70426@e0-0.zab2.int.zabbadoz.net> <200501181124.19323.jhb@FreeBSD.org> <4340E785.3030705@cronyx.ru>
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On Monday 03 October 2005 04:10 am, Roman Kurakin wrote: > Hi, > > Could you check: > > http://lists.freebsd.org/pipermail/freebsd-current/2005-September/056078.ht >ml > > Best regards, > rik If it doesn't trigger any other LORs then it is probably fine. > John Baldwin wrote: > >On Monday 17 January 2005 05:07 pm, Bjoern A. Zeeb wrote: > >>Hi, > >> > >>I have added the following as LOR #055 to "the LOR page"[1]. > >> > >>lock order reversal > >> 1st 0xffffffff80c3a9e8 sleep mtxpool (sleep mtxpool) @ > >>sys/kern/kern_descrip.c:2277 2nd 0xffffff00222d8a48 filedesc structure > >>(filedesc structure) @ sys/kern/kern_descrip.c:2278 KDB: stack backtrace: > >>witness_checkorder() at witness_checkorder+0x5f1 > >>_mtx_lock_flags() at _mtx_lock_flags+0x4a > >>dupfdopen() at dupfdopen+0x320 > >>kern_open() at kern_open+0x5de > >>syscall() at syscall+0x4ab > >>Xfast_syscall() at Xfast_syscall+0xa8 > >>--- syscall (5, FreeBSD ELF64, open), rip = 0x80077e7d0, rsp = > >>0x7fffffffe6f8, rbp = 0x7fffffffec70 --- > >> > >>I can easily reproduce it every boot. It seems to be triggered by > >>Capi4BSD[2] framework which I incorporated in my private tree. > >> > >>Can someone please comment on this ? > > > >The problem is that FILEDESC_UNLOCK() actually includes an entirely > > separate lock of its own (it's like an sx lock sort of). One possible > > fix might be to change struct file to either use a dedicated mutex pool > > (instead of the more generic mtxpool_sleep one that is intended only for > > leaf-lock usage) or to have each struct file include its own mutex rather > > than using a pool lock. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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