Processes spinning forever, apparently in lock_timer_base()?

Chuck Ebbert
2007-08-01T22:40:32Z

Looks like the same problem with spinlock unfairness we've seen
elsewhere: it seems to be looping here? Or is everyone stuck
just waiting for writeout?

lock_timer_base():
for (;;) {
tvec_base_t *prelock_base = timer->base;
base = tbase_get_base(prelock_base);
if (likely(base != NULL)) {
spin_lock_irqsave(&base->lock, *flags);
if (likely(prelock_base == timer->base))
return base;
/* The timer has migrated to another CPU */
spin_unlock_irqrestore(&base->lock, *flags);
}
cpu_relax();
}

The problem goes away completely if filesystem are mounted
*without* noatime. Has happened in 2.6.20 through 2.6.22...

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=249563

Part of sysrq-t listing:

mysqld D 000017c0 2196 23162 1562
e383fcb8 00000082 61650954 000017c0 e383fc9c 00000000 c0407208 e383f000
a12b0434 00004d1d c6ed2c00 c6ed2d9c c200fa80 00000000 c0724640 f6c60540
c4ff3c70 00000508 00000286 c042ffcb e383fcc8 00014926 00000000 00000286
Call Trace:
[<c0407208>] do_IRQ+0xbd/0xd1
[<c042ffcb>] lock_timer_base+0x19/0x35
[<c04300df>] __mod_timer+0x9a/0xa4
[<c060bb55>] schedule_timeout+0x70/0x8f
[<c042fd37>] process_timeout+0x0/0x5
[<c060bb50>] schedule_timeout+0x6b/0x8f
[<c060b67c>] io_schedule_timeout+0x39/0x5d
[<c0465eea>] congestion_wait+0x50/0x64
[<c0438539>] autoremove_wake_function+0x0/0x35
[<c04620e2>] balance_dirty_pages_ratelimited_nr+0x148/0x193
[<c045e7fd>] generic_file_buffered_write+0x4c7/0x5d3

named D 000017c0 2024 1454 1
f722acb0 00000082 6165ed96 000017c0 c1523e80 c16f0c00 c16f20e0 f722a000
a12be87d 00004d1d f768ac00 f768ad9c c200fa80 00000000 00000000 f75bda80
c0407208 00000508 00000286 c042ffcb f722acc0 00020207 00000000 00000286
Call Trace:
[<c0407208>] do_IRQ+0xbd/0xd1
[<c042ffcb>] lock_timer_base+0x19/0x35
[<c04300df>] __mod_timer+0x9a/0xa4
[<c060bb55>] schedule_timeout+0x70/0x8f
[<c042fd37>] process_timeout+0x0/0x5
[<c060bb50>] schedule_timeout+0x6b/0x8f
[<c060b67c>] io_schedule_timeout+0x39/0x5d
[<c0465eea>] congestion_wait+0x50/0x64
[<c0438539>] autoremove_wake_function+0x0/0x35
[<c04620e2>] balance_dirty_pages_ratelimited_nr+0x148/0x193
[<c045e7fd>] generic_file_buffered_write+0x4c7/0x5d3

mysqld D 000017c0 2196 23456 1562
e9293cb8 00000082 616692ed 000017c0 e9293c9c 00000000 e9293cc8 e9293000
a12c8dd0 00004d1d c3d5ac00 c3d5ad9c c200fa80 00000000 c0724640 f6c60540
e9293d10 c07e1f00 00000286 c042ffcb e9293cc8 0002b57f 00000000 00000286
Call Trace:
[<c042ffcb>] lock_timer_base+0x19/0x35
[<c04300df>] __mod_timer+0x9a/0xa4
[<c060bb55>] schedule_timeout+0x70/0x8f
[<c042fd37>] process_timeout+0x0/0x5
[<c060bb50>] schedule_timeout+0x6b/0x8f
[<c060b67c>] io_schedule_timeout+0x39/0x5d
[<c0465eea>] congestion_wait+0x50/0x64
[<c0438539>] autoremove_wake_function+0x0/0x35
[<c04620e2>] balance_dirty_pages_ratelimited_nr+0x148/0x193
[<c045e7fd>] generic_file_buffered_write+0x4c7/0x5d3