Date: Sat, 24 Oct 2009 00:21:04 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Dylan Cochran <heliocentric@gmail.com> Cc: "freebsd-stable@freebsd.org" <freebsd-stable@freebsd.org> Subject: Re: Possible scheduler (SCHED_ULE) bug? Message-ID: <20091023212104.GH2160@deviant.kiev.zoral.com.ua> In-Reply-To: <bdf82f800910231328tfa4decfncd70ae0daad2bef6@mail.gmail.com> References: <CF092998EA82AE4D83AF9C9ECA9A8BDE02EB411A85@ATLAS.msg.local> <bdf82f800910231328tfa4decfncd70ae0daad2bef6@mail.gmail.com>
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--c5s4KQzYKKhDo6IA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 23, 2009 at 04:28:59PM -0400, Dylan Cochran wrote: > On 10/23/09, Jaime Bozza <jbozza@mindsites.com> wrote: > > I believe I found a problem with the ULE scheduler - At least the fact = that > > there is a problem, but I'm not sure where to go from here. The system > > locks all processes, but doesn't panic, so I have no output to give. > > > > I was able to duplicate this on three different machines and solved it = by > > switching to the scheduler to 4BSD. > > > > Here's the environment: > > > > FreeBSD 7.2 i386, installed from bootonly ISO, Custom install, minimal,= no > > other changes other than setting timezone, changing root password, and > > turning on sshd (allowing root and password connection). > > > > Running portsnap (fetch, then extract) to get latest ports tree. > > > > >From ports, make installs of lang/php5 and www/lighttpd, using default= s for > > all ports installed. > > > > Modified lighttpd.conf for PHP (attached diff), created a short script > > called uploadfile.php (attached). File was installed at > > /usr/local/www/data/uploadfile.php > > > > Start lighttpd (lighttpd_enable=3D"YES" in rc.conf, > > /usr/local/etc/rc.d/lighttpd start), connect and run script. > > > > As long as I upload a file less than 64K, everything works fine. If I = try > > to upload something larger than 64K, system no longer responds. Conso= le > > prompt at login will allow me to enter username/password, but nothing > > happens after that. Console prompt logged in will allow me to type a s= ingle > > line, but if I press enter, nothing after that. > > > > No errors get written anywhere - console, logs, etc. > > > > I'm at a loss of what to do next. Can anyone give me ideas of what els= e I > > can do? >=20 > Superficially, this seams identical to a deadlock I reported for > 7.1-RC1. Would you mind compiling a kernel with these options: >=20 > options DDB > options KDB > options SW_WATCHDOG > options DEBUG_VFS_LOCKS >=20 >=20 > then add the following to /etc/rc.conf: >=20 > watchdogd_enable=3D"YES" > watchdogd_flags=3D"-e 'ls -al /etc'" >=20 > This should force a panic when the lockup happens again, which will > drop to a debugger. >=20 > Please check the backtrace, and tell me if the call stack is the same > as this one (between the --- interrupt, and --- syscall sections): >=20 > KDB: stack backtrace: > db_trace_self_wrapper(c0b55b52,e66e0ae0,c07615e9,c0b50617,8ca93,...) > at db_trace_self_wrapper+0x26 > kdb_backtrace(c0b50617,8ca93,0,c41a7690,2,...) at kdb_backtrace+0x29 > hardclock(0,c07ff29d,0,0,4,...) at hardclock+0x1f9 > lapic_handle_timer(e66e0b08) at lapic_handle_timer+0x9c > Xtimerint() at Xtimerint+0x1f > --- interrupt, eip =3D 0xc07ff29d, esp =3D 0xe66e0b48, ebp =3D 0xe66e0c34= --- > kern_sendfile(c41a7690,e66e0cfc,0,0,0,...) at kern_sendfile+0x90d > do_sendfile(e66e0d2c,c0aba265,c41a7690,e66e0cfc,20,...) at do_sendfile+0x= b1 > sendfile(c41a7690,e66e0cfc,20,16,e66e0d2c,...) at sendfile+0x13 > syscall(e66e0d38) at syscall+0x335 > Xint0x80_syscall() at Xint0x80_syscall+0x20 > --- syscall (393, FreeBSD ELF32, sendfile), eip =3D 0x282cb0cb, esp =3D > 0xbfbfc7cc, ebp =3D 0xbfbfe848 --- > KDB: enter: watchdog timeout Can you look up the source line for kern_sendfile+0x90d in your kernel ? Do kgdb kernel.debug, then execute "list *(kern_sendfile+0x90d)". --c5s4KQzYKKhDo6IA Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkriHkAACgkQC3+MBN1Mb4i1YwCg4Mjn8r+5R1w+yPhgb7BTmAKb hy0AnAwMCgcB+au+TeqM3I1JQGjcxCkL =5VbK -----END PGP SIGNATURE----- --c5s4KQzYKKhDo6IA--
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