linux-sg2042/kernel/irq
Jarek Poplawski 59845b1ffd request_irq: fix DEBUG_SHIRQ handling
Mariusz Kozlowski reported lockdep's warning:

> =================================
> [ INFO: inconsistent lock state ]
> 2.6.23-rc2-mm1 #7
> ---------------------------------
> inconsistent {in-hardirq-W} -> {hardirq-on-W} usage.
> ifconfig/5492 [HC0[0]:SC0[0]:HE1:SE1] takes:
>  (&tp->lock){+...}, at: [<de8706e0>] rtl8139_interrupt+0x27/0x46b [8139too]
> {in-hardirq-W} state was registered at:
>   [<c0138eeb>] __lock_acquire+0x949/0x11ac
>   [<c01397e7>] lock_acquire+0x99/0xb2
>   [<c0452ff3>] _spin_lock+0x35/0x42
>   [<de8706e0>] rtl8139_interrupt+0x27/0x46b [8139too]
>   [<c0147a5d>] handle_IRQ_event+0x28/0x59
>   [<c01493ca>] handle_level_irq+0xad/0x10b
>   [<c0105a13>] do_IRQ+0x93/0xd0
>   [<c010441e>] common_interrupt+0x2e/0x34
...
> other info that might help us debug this:
> 1 lock held by ifconfig/5492:
>  #0:  (rtnl_mutex){--..}, at: [<c0451778>] mutex_lock+0x1c/0x1f
>
> stack backtrace:
...
>  [<c0452ff3>] _spin_lock+0x35/0x42
>  [<de8706e0>] rtl8139_interrupt+0x27/0x46b [8139too]
>  [<c01480fd>] free_irq+0x11b/0x146
>  [<de871d59>] rtl8139_close+0x8a/0x14a [8139too]
>  [<c03bde63>] dev_close+0x57/0x74
...

This shows that a driver's irq handler was running both in hard interrupt
and process contexts with irqs enabled. The latter was done during
free_irq() call and was possible only with CONFIG_DEBUG_SHIRQ enabled.
This was fixed by another patch.

But similar problem is possible with request_irq(): any locks taken from
irq handler could be vulnerable - especially with soft interrupts. This
patch fixes it by disabling local interrupts during handler's run. (It
seems, disabling softirqs should be enough, but it needs more checking
on possible races or other special cases).

Reported-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31 01:42:23 -07:00
..
Makefile [PATCH] sort the devres mess out 2007-02-11 11:18:07 -08:00
autoprobe.c [PATCH] genirq: add handle_bad_irq() 2006-06-29 10:26:24 -07:00
chip.c genirq: cleanup mismerge artifact 2007-08-12 11:05:45 -07:00
devres.c rip some includes from linux/interrupt.h 2007-07-28 19:42:22 -07:00
handle.c Fix Linuxdoc comment 2007-05-09 12:30:48 -07:00
internals.h [PATCH] genirq: more verbose debugging on unexpected IRQ vectors 2006-06-29 10:26:25 -07:00
manage.c request_irq: fix DEBUG_SHIRQ handling 2007-08-31 01:42:23 -07:00
migration.c [PATCH] genirq: Mask irqs when migrating them. 2007-02-26 10:34:08 -08:00
proc.c x86_64: Report the pending irq if available in smp_affinity 2007-07-21 18:37:07 -07:00
resend.c genirq: suppress resend of level interrupts 2007-08-12 11:05:45 -07:00
spurious.c Improve behaviour of spurious IRQ detect 2007-07-16 09:05:46 -07:00