Date: Sun, 13 May 2012 22:29:20 +0200 From: Mateusz Guzik <mjguzik@gmail.com> To: Andrey Zonov <andrey@zonov.org> Cc: trasz@freebsd.org, freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: panic with overcommit and RACCT Message-ID: <20120513202920.GA18238@dft-labs.eu> In-Reply-To: <4FAFEEEF.3040706@zonov.org> References: <4FAFEEEF.3040706@zonov.org>
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On Sun, May 13, 2012 at 09:27:11PM +0400, Andrey Zonov wrote: > Hi, > > I've got a repeatable panic on latest 9.0-STABLE and HEAD with > turned on overcommit (vm.overcommit=1) and RACCT. > > kgdb trace on today's HEAD: > > #10 0xffffffff80bc3513 in calltrap () > at /usr/src/sys/amd64/amd64/exception.S:228 > #11 0xffffffff808aab71 in racct_set_locked (p=0xfffffe0005d684a0, > resource=0, > amount=2680) at /usr/src/sys/kern/kern_racct.c:372 > #12 0xffffffff808ab645 in racct_proc_exit (p=0xfffffe0005d684a0) > at /usr/src/sys/kern/kern_racct.c:615 > #13 0xffffffff80880d69 in fork1 (td=0xfffffe0005b2c460, flags=20, pages=4, > procp=0xffffff811a36bb00, procdescp=Variable "procdescp" is not > available. > ) at /usr/src/sys/kern/kern_fork.c:943 > #14 0xffffffff80882362 in sys_fork (td=0xfffffe0005b2c460, > uap=Variable "uap" is not available. > ) > at /usr/src/sys/kern/kern_fork.c:110 > #15 0xffffffff80bd7a89 in amd64_syscall (td=0xfffffe0005b2c460, traced=0) > at subr_syscall.c:135 > #16 0xffffffff80bc37f7 in Xfast_syscall () > at /usr/src/sys/amd64/amd64/exception.S:387 > #17 0x00000008024729fc in ?? () > Previous frame inner to this frame (corrupt stack?) > (kgdb) > > Unread portion of the kernel message buffer: > Kernel page fault with the following non-sleepable locks held: > exclusive sleep mutex racct lock (racct lock) r = 0 > (0xffffffff8128a7c0) locked @ /usr/src/sys/kern/kern_racct.c:614 > exclusive sleep mutex process lock (process lock) r = 0 > (0xfffffe0005d68598) locked @ /usr/src/sys/kern/kern_racct.c:603 > It looks like racct_proc_exit can be called for processes without properly initialized racct structure, which in turn results in this panic. Can you please test this patch: http://student.agh.edu.pl/~mjguzik/patches/racct-fork.patch ? I was unable to reproduce panic you describe, so it was tested only by manually injecting error. Nevertheless I think you should try it. :) -- Mateusz Guzik <mjguzik gmail.com>
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