Re: 2.6.38.x: system hangs, iowait ~75, no resource-hogs, no logs
From: Kelly Anderson
Date: Thu Apr 07 2011 - 19:14:24 EST
On 04/07/11 16:21, Thomas Sattler wrote:
Hi there ...
I observed three system hangs since 2.6.38 (two times 2.6.38,
once 2.6.38.2). I have no idea what triggers the problem, I
cannot find the cause myself. I tried these:
top:
~~~~
- no cpu-hogg, still a bit free RAM, lots of free SWAP
- iowait is constantly high at ~75%, I don't know why
dmesg, /var/log/*:
~~~~~~~~~~~~~~~~~~
Nothing in 'dmesg', nothing in the logfiles.
pkill / iotop / ps:
~~~~~~~~~~~~~~~~~~~
they all hang quite soon, no reaction on Ctrl-C. While 'ps'
shows some lines of output, 'pkill' and 'iotop' just hang.
vmstat 1:
~~~~~~~~~
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 4 72 421008 54560 326652 0 0 0 0 518 1293 25 9 0 66
0 4 72 421008 54560 326652 0 0 0 0 311 535 13 4 0 83
2 4 72 420208 54560 326652 0 0 0 0 450 882 18 9 0 73
0 4 72 421008 54560 326652 0 0 0 0 377 914 19 5 0 76
(I collected about 90 lines, there's not much to be seen.)
I run 'strace -o dump command' with iotop, ps and su.
(And lost a tty to each of them.)
$ tail dump_*
==> dump_iotop<==
fstat64(9, {st_mode=S_IFREG|0644, st_size=2952, ...}) = 0
mmap2(NULL, 2952, PROT_READ, MAP_SHARED, 9, 0) = 0xb6d80000
_llseek(9, 2952, [2952], SEEK_SET) = 0
munmap(0xb6d80000, 2952) = 0
close(9) = 0
open("/proc/5904/cmdline", O_RDONLY|O_LARGEFILE) = 9
fstat64(9, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
fstat64(9, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6d80000
read(9,
==> dump_ps<==
stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2309, ...}) = 0
stat64("/proc/5904", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0
open("/proc/5904/stat", O_RDONLY) = 6
read(6, "5904 (thunderbird-bin) D 5900 58"..., 1023) = 242
close(6) = 0
open("/proc/5904/status", O_RDONLY) = 6
read(6, "Name:\tthunderbird-bin\nState:\tD ("..., 1023) = 836
close(6) = 0
open("/proc/5904/cmdline", O_RDONLY) = 6
read(6,
==> dump_su<==
stat64("/home/tsattler/.pam_environment", 0xbffdb3e0) = -1 ENOENT (No such
file or directory)
access("/usr/bin/xauth", X_OK) = 0
setuid32(1000) = 0
chdir("/home/tsattler") = 0
close(3) = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
child_tidptr=0xb75f3728) = 25247
rt_sigprocmask(SIG_BLOCK, ~[RTMIN RT_1], NULL, 8) = 0
rt_sigaction(SIGTERM, {0x8049ce0, [], 0}, NULL, 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [ALRM TERM], NULL, 8) = 0
waitpid(-1,
'top' showed constantly increasing sysload, I rebooted
(via Alt-SysRq-[S][U][B]) at a load of about 25-30.
My system is as follows:
~~~~~~~~~~~~~~~~~~~~~~~~
IBM T41p, 1.5GB RAM, 4GB SWAP (nearly unused), two HDs
160/80GB. Gentoo Linux, kernel 2.6.38.2 (vanilla sources).
I compiled the kernel myself. I skipped 2.6.37 but run
2.6.36.3 with sabayon's fourth version of a backport of
sched-automated-per-session-task-groups.patch for more
than two months without any problems.
CPU-Speed is 1700MHz (hardware) but I run the machine
at 1400MHz most of the time as the fans become loud
when running at full speed.
** Please CC: me, as I'm not on the list. **
Thomas
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Try the patch found in "Linux 2.6.38 freeze because of
sound/core/pcm_lib.c commit"
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