Re: [patch] warn on release_region() from irq context

From: Ingo Molnar
Date: Sat Jan 28 2006 - 10:15:12 EST


the rationale for this patch is that the lock validator (which now
tracks rwlock dependencies too, see output below) noticed that floppy.c
does a release_region() from softirq context -> ouch. I'm working on the
floppy.c fix for that.

Ingo

============================
[ BUG: illegal lock usage! ]
----------------------------
illegal {softirq-on} -> {in-softirq} usage.
rcu_torture_rea/264 [HC0[0]:SC1[2]:HE1:SE0] takes:
(resource_lock){+-}, at: [<c0123997>] __release_region+0x37/0xf0
{softirq-on} state was registered at:
[<c0122c85>] irq_exit+0x45/0x50
hardirqs last enabled at: [<c011d39e>] vprintk+0x32e/0x3e0
softirqs last enabled at: [<c0122c85>] irq_exit+0x45/0x50

other info that might help us debug this:
no locks held by rcu_torture_rea/264.

stack backtrace:
[<c010432d>] show_trace+0xd/0x10
[<c0104347>] dump_stack+0x17/0x20
[<c0139078>] print_usage_bug+0x1d8/0x230
[<c0139436>] mark_lock+0x366/0x3a0
[<c0139903>] debug_lock_chain+0x493/0x1090
[<c013a53d>] debug_lock_chain_spin+0x3d/0x60
[<c0268522>] _raw_write_lock+0x32/0x1a0
[<c04dc158>] _write_lock+0x8/0x10
[<c0123997>] __release_region+0x37/0xf0
[<c02f5010>] floppy_release_irq_and_dma+0x140/0x200
[<c02f3577>] set_dor+0xc7/0x1b0
[<c02f65e1>] motor_off_callback+0x21/0x30
[<c01276c5>] run_timer_softirq+0xf5/0x1f0
[<c0122fc7>] __do_softirq+0x97/0x130
[<c01054a9>] do_softirq+0x69/0x100
=======================
[<c0122c85>] irq_exit+0x45/0x50
[<c010f504>] smp_apic_timer_interrupt+0x54/0x60
[<c010393b>] apic_timer_interrupt+0x27/0x2c
[<c0266b79>] __delay+0x9/0x10
[<c0266be1>] __udelay+0x31/0x40
[<c01445e3>] rcu_torture_reader+0x83/0x140
[<c0131cca>] kthread+0xca/0xd0
[<c0100ef5>] kernel_thread_helper+0x5/0x10
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