hello,

I'm getting this warning in dmesg since 2.6.28-next-20081229:

WARNING: at kernel/sched.c:4435 sub_preempt_count+0x7e/0x8f()
Hardware name: M68SM-S2L
Modules linked in:
Pid: 0, comm: swapper Not tainted 2.6.28-next-20090107-09542-gdbcea38 #71
Call Trace:
 [<c0224f35>] warn_slowpath+0x80/0xb6
 [<c024140d>] lock_acquire+0x76/0x7e
 [<c03be817>] _spin_unlock_irq+0x20/0x51
 [<c0240278>] trace_hardirqs_on_caller+0xf8/0x12e
 [<c03be81f>] _spin_unlock_irq+0x28/0x51
 [<c03be83c>] _spin_unlock_irq+0x45/0x51
 [<c022c865>] run_timer_softirq+0x178/0x180
 [<c022211c>] run_rebalance_domains+0x27/0x8f
 [<c023ef58>] trace_hardirqs_off_caller+0x2c/0x87
 [<c0220788>] sub_preempt_count+0x7e/0x8f
 <IRQ>  [<c024ef74>] handle_level_irq+0x0/0x9d
 [<c022950e>] irq_exit+0x43/0x87
 [<c0204d9e>] do_IRQ+0xec/0x102
 [<c02035ec>] common_interrupt+0x2c/0x34
 [<c02168dc>] native_safe_halt+0x2/0x3
 [<c04aadd3>] check_bugs+0x9f/0xd8
 [<c04a47e8>] start_kernel+0x2f9/0x306
---[ end trace 4eaa2a86a8e2da22 ]---

In previous releases (2.6.27-next-20081020 to 2.6.28-rc7-next-20081203), I was getting "WARNING: at kernel/sched.c:4354 do_softirq" with more or less the same stack trace:

Checking 'hlt' instruction... <4>------------[ cut here ]------------
WARNING: at kernel/sched.c:4332 do_softirq+0x61/0xb3()
Modules linked in:
Pid: 0, comm: swapper Not tainted 2.6.28-rc2-next-20081027-02513-g5362c2b #46
Call Trace:
 [<c02234b8>] warn_on_slowpath+0x40/0x59
 [<c023e07b>] trace_hardirqs_on_caller+0xe3/0x12d
 [<c03b295a>] _spin_unlock_irq+0x3c/0x48
 [<c0220deb>] run_rebalance_domains+0x29/0x96
 [<c022793f>] __do_softirq+0xc5/0xf9
 [<c022787a>] __do_softirq+0x0/0xf9
 <IRQ>  [<c024bf72>] handle_level_irq+0x0/0x9f
 [<c02279b6>] irq_exit+0x43/0x8b
 [<c0205eec>] do_IRQ+0xef/0x107
 [<c0204628>] common_interrupt+0x28/0x30
 [<c04cfadf>] check_bugs+0x91/0xbb
 [<c04c782c>] start_kernel+0x308/0x318
---[ end trace 4eaa2a86a8e2da22 ]---
OK.


Full dmesg and .config for 2.6.28-next-20090107 are attached (actually this is linux-next tree + reiser4 patches, but I verified that this WARNING does appear without reiser4 patches in 2.6.28-next-20081230).
 
~~
laurent