Date: Thu, 22 Aug 2013 12:13:41 +0200 From: Yamagi Burmeister <lists@yamagi.org> To: freebsd-fs@freebsd.org Cc: trociny@freebsd.org Subject: Re: 9.2-RC1: LORs / Deadlock with SU+J on HAST in "memsync" mode Message-ID: <20130822121341.0f27cb5e372d12bab8725654@yamagi.org> In-Reply-To: <20130819115101.ae9c0cf788f881dc4de464c5@yamagi.org> References: <20130819115101.ae9c0cf788f881dc4de464c5@yamagi.org>
next in thread | previous in thread | raw e-mail | index | archive | help
--Signature=_Thu__22_Aug_2013_12_13_41_+0200_1edTGGGYQbPa+y4n Content-Type: text/plain; charset=US-ASCII Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello Mikolaj and Pawel, I've been told that the issue below is most likely a problem with HAST. Since it's your pet your're my next victims. :) A short summary: After having some systems upgraded to FreeBSD 9.2-RC1/RC2 and switched HAST to the new "memsync" mode I've seen processes getting stuck when accessing files on UFS filesystems with SU+J enabled. Testing showed that this only seems to happen (while I couldn't reproduce it in other combinations I'm not quite sure if its really the case) when HAST is running in "memsync" mode and the UFS filesystem on HAST has SU+J enabled. It can be reproduced easily with the instructions below.=20 Since my first mail I've done another DDB session, bit I'm not sure if it's helpfull since I focused on deadlocks. It can be found here: http://deponie.yamagi.org/freebsd/debug/lor_hast/ddb2.txt Some help with this issue would be appreciated. At leats for me HAST is currently usable when running in "memsync" mode with UFS and SU+J on it. As said before, more information can be provided. Ciao, Yamagi On Mon, 19 Aug 2013 11:51:01 +0200 Yamagi Burmeister <lists@yamagi.org> wrote: > Hello, > in the last week I've seen several deadlocked processes (stucked in > state "vofflock" or "wswbuf0" on an UFS2 filesystem with SU+J on HAST > with "memsync" mode. TheThe deadlock disappear if either SU+J is > disabled (only SU are active) or HAST is switched to "fullsync" mode. >=20 > The system is: > FreeBSD tvtransfer.local 9.2-RC1 FreeBSD 9.2-RC1 #0 r254355M: > Fri Aug 16 12:35:30 UTC 2013 > support@tvtransfer.local:/usr/obj/usr/src/sys/GENERIC amd64 >=20 > I've build a kernel with full debugging support and seen this two LOR > beside the known false positive between bufwait and dirhash: >=20 > lock order reversal: > 1st 0xfffffe0197310d68 ufs (ufs) @ /usr/src/sys/kern/vfs_subr.c:2223 > 2nd 0xffffff87be8be0f8 bufwait (bufwait) > @ /usr/src/sys/ufs/ffs/ffs_vnops.c:261 3rd 0xfffffe019746f098 ufs (ufs) > @ /usr/src/sys/kern/vfs_subr.c:2223 KDB: stack backtrace: > db_trace_self_wrapper() at db_trace_self_wrapper+0x2a/frame > 0xffffff88715dcd50 kdb_backtrace() at kdb_backtrace+0x37/frame > 0xffffff88715dce10 _witness_debugger() at _witness_debugger+0x2c/frame > 0xffffff88715dce30 witness_checkorder() at witness_checkorder > +0x875/frame 0xffffff88715dcef0 __lockmgr_args() at __lockmgr_args > +0x1141/frame 0xffffff88715dcfd0 ffs_lock() at ffs_lock+0x9c/frame > 0xffffff88715dd020 VOP_LOCK1_APV() at VOP_LOCK1_APV+0xe3/frame > 0xffffff88715dd050 _vn_lock() at _vn_lock+0x55/frame 0xffffff88715dd0b0 > vget() at vget+0x7b/frame 0xffffff88715dd100 > vfs_hash_get() at vfs_hash_get+0xd5/frame 0xffffff88715dd150 > ffs_vgetf() at ffs_vgetf+0x48/frame 0xffffff88715dd1d0 > softdep_sync_buf() at softdep_sync_buf+0x547/frame 0xffffff88715dd2a0 > ffs_syncvnode() at ffs_syncvnode+0x2c1/frame 0xffffff88715dd310 > ffs_truncate() at ffs_truncate+0x10bb/frame 0xffffff88715dd560 > ufs_direnter() at ufs_direnter+0x550/frame 0xffffff88715dd630 > ufs_makeinode() at ufs_makeinode+0x355/frame 0xffffff88715dd7f0 > VOP_CREATE_APV() at VOP_CREATE_APV+0x102/frame 0xffffff88715dd820 > vn_open_cred() at vn_open_cred+0x45e/frame 0xffffff88715dd990 > kern_openat() at kern_openat+0x20a/frame 0xffffff88715ddb10 > amd64_syscall() at amd64_syscall+0x2f9/frame 0xffffff88715ddc30 > Xfast_syscall() at Xfast_syscall+0xf7/frame 0xffffff88715ddc30 > --- syscall (5, FreeBSD ELF64, sys_open), rip =3D 0x800b38d3c, rsp =3D > 0x7fffffffd128, rbp =3D 0x7fffffffda40 ---=20 >=20 > lock order reversal: > 1st 0xfffffe0035dfbf30 so_snd_sx (so_snd_sx) > @ /usr/src/sys/kern/uipc_sockbuf.c:145 2nd 0xfffffe02ead2b328 ufs (ufs) > @ /usr/src/sys/kern/uipc_syscalls.c:2062 KDB: stack backtrace: > db_trace_self_wrapper() at db_trace_self_wrapper+0x2a/frame > 0xffffff8871515530 kdb_backtrace() at kdb_backtrace+0x37/frame > 0xffffff88715155f0 _witness_debugger() at _witness_debugger+0x2c/frame > 0xffffff8871515610 witness_checkorder() at witness_checkorder > +0x875/frame 0xffffff88715156d0 __lockmgr_args() at __lockmgr_args > +0x1446/frame 0xffffff88715157b0 ffs_lock() at ffs_lock+0x9c/frame > 0xffffff8871515800 VOP_LOCK1_APV() at VOP_LOCK1_APV+0xe3/frame > 0xffffff8871515830 _vn_lock() at _vn_lock+0x55/frame 0xffffff8871515890 > kern_sendfile() at kern_sendfile+0x8e7/frame 0xffffff8871515ab0 > do_sendfile() at do_sendfile+0xdc/frame 0xffffff8871515b10 > amd64_syscall() at amd64_syscall+0x2f9/frame 0xffffff8871515c30 > Xfast_syscall() at Xfast_syscall+0xf7/frame 0xffffff8871515c30 > --- syscall (393, FreeBSD ELF64, sys_sendfile), rip =3D 0x8022075bc, rsp > =3D 0x7fffffffb268, rbp =3D 0x7fffffffd570 --- >=20 > Both LORs can be found in a more readable format here: > http://deponie.yamagi.org/freebsd/debug/lor_hast/lor.txt >=20 > The transcript of a DDB session with all informations requested in > chapter "10.7. Debugging Deadlocks" of the developers handbook can > be found here: > http://deponie.yamagi.org/freebsd/debug/lor_hast/ddb.txt >=20 > Reproducing this problem is easy: > 1. Create a HAST setup in "memsync" mode with both primary and > secondary connected > 2. "newfs -U -j /dev/hast/$device" on the primary > 3. mount "mount /dev/hast/$device /mnt" > 4. Create some load on /mnt. For example copy /usr/ports in > an endless loop. Sooner or later processes accessing /mnt > will deadlock. This may be easer to reproduce while HAST > is performing the initial sync. >=20 > More information can be provided if necessary. >=20 > Thanks, > Yamagi >=20 > --=20 > Homepage: www.yamagi.org > XMPP: yamagi@yamagi.org > GnuPG/GPG: 0xEFBCCBCB --=20 Homepage: www.yamagi.org XMPP: yamagi@yamagi.org GnuPG/GPG: 0xEFBCCBCB --Signature=_Thu__22_Aug_2013_12_13_41_+0200_1edTGGGYQbPa+y4n Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) iEYEARECAAYFAlIV5FsACgkQWTjlg++8y8vAsQCePDi5/Xerr+f03wsHtkNzPYfI kYgAnim9Z/ZEw3zBIz38W9qNBw4epFma =Iecv -----END PGP SIGNATURE----- --Signature=_Thu__22_Aug_2013_12_13_41_+0200_1edTGGGYQbPa+y4n--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20130822121341.0f27cb5e372d12bab8725654>