Date: Sun, 22 Feb 2015 15:00:25 -0800 From: Sean Bruno <sbruno@ignoranthack.me> To: freebsd-current@freebsd.org Subject: Re: panic on application core dump? Message-ID: <54EA5F89.1010102@ignoranthack.me> In-Reply-To: <54EA25FE.60401@ignoranthack.me> References: <54E8EA2A.7020904@ignoranthack.me> <20150221211712.GG74514@kib.kiev.ua> <54EA1325.6070009@ignoranthack.me> <20150222180425.GJ74514@kib.kiev.ua> <54EA241D.6020606@ignoranthack.me> <20150222185352.GL74514@kib.kiev.ua> <54EA25FE.60401@ignoranthack.me>
next in thread | previous in thread | raw e-mail | index | archive | help
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
On 02/22/15 10:54, Sean Bruno wrote:
> On 02/22/15 10:53, Konstantin Belousov wrote:
>> On Sun, Feb 22, 2015 at 10:46:53AM -0800, Sean Bruno wrote:
>>> Hmm ... looks unrelated to signals (maybe). This looks like a
>>> common ZFS deadlock that is yet undiagnosed. I do not have a
>>> show alllocks command available in db> . I will show each
>>> lock information below:
>> Add witness.
>
>>>
>>> db> show lockedvnods Locked vnodes
>>>
>>> 0xfffff801141a6588: tag zfs, type VDIR usecount 19, writecount
>>> 0, refcount 20 mountedhere 0 flags (VV_ROOT|VI_ACTIVE)
>>> v_object 0xfffff80079be4500 ref 0 pages 0 cleanbuf 0 dirtybuf 0
>>> lock type zfs: EXCL by thread 0xfffff801ca10c4a0 (pid 75907,
>>> sh, tid 101262) with exclusive waiters pending
>> Without backtraces of the acquisition, it is not useful. You
>> need DEBUG_VFS_LOCKS for this.
>
>
>
> Thank you. I will do so and restart my non-determinstic test and
> see what I can find.
>
> sean _______________________
Well, that was certainly enlightening. I was able to get a WITNESS
panic in imgact_binmisc.c in an hour or two. I need to *not* hold the
mtx protecting the list of activators over the bcopy in
imgact_binmisc_exec().
Jiles proposes that we switch to an sx lock here for simplicity of
change of the code.
Kernel page fault with the following non-sleepable locks held:
exclusive sleep mutex imgact_binmisc (imgact_binmisc) r = 0
(0xffffffff82012418) locked @
/usr/src/sys/modules/imgact_binmisc/../../kern/imgact_binmisc.c:596
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
0xfffffe046a236280
witness_warn() at witness_warn+0x4ae/frame 0xfffffe046a236350
trap_pfault() at trap_pfault+0x59/frame 0xfffffe046a2363f0
trap() at trap+0x45e/frame 0xfffffe046a236600
calltrap() at calltrap+0x8/frame 0xfffffe046a236600
- --- trap 0xc, rip = 0xffffffff80d21279, rsp = 0xfffffe046a2366c0, rbp
= 0xfffffe046a2366d0 ---
bcopy() at bcopy+0x39/frame 0xfffffe046a2366d0
imgact_binmisc_exec() at imgact_binmisc_exec+0x23d/frame
0xfffffe046a236720
kern_execve() at kern_execve+0x4c6/frame 0xfffffe046a236a80
sys_execve() at sys_execve+0x37/frame 0xfffffe046a236ae0
amd64_syscall() at amd64_syscall+0x27f/frame 0xfffffe046a236bf0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe046a236bf0
- --- syscall (59, FreeBSD ELF64, sys_execve), rip = 0x4297ba, rsp =
0x7fffffffdaf8, rbp = 0x7fffffffdb00 ---
Fatal trap 12: page fault while in kernel mode
cpuid = 13; apic id = 33
fault virtual address = 0xfffffe0456c01007
fault code = supervisor write data, page not present
instruction pointer = 0x20:0xffffffff80d21279
stack pointer = 0x28:0xfffffe046a2366c0
frame pointer = 0x28:0xfffffe046a2366d0
code segment = base 0x0, limit 0xfffff, type 0x1b
= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 27028 (cc)
[ thread pid 27028 tid 100872 ]
Stopped at bcopy+0x39: repe movsb (%rsi),%es:(%rdi)
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2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=
=MwoX
-----END PGP SIGNATURE-----
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?54EA5F89.1010102>