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authorJarek Poplawski <jarkao2@o2.pl>2007-08-30 23:56:34 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-08-31 01:42:23 -0700
commit59845b1ffd9121e5ef474ea5f27405fd7a83c85b (patch)
tree9f7c073327138b7c5bb0193229244dbdd5444113 /kernel
parent2aeb3db17fc33443d21b11d7121c5627d55717c6 (diff)
downloadlinux-linaro-59845b1ffd9121e5ef474ea5f27405fd7a83c85b.tar.gz
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/manage.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 853aefbd184..7230d914eaa 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -547,14 +547,11 @@ int request_irq(unsigned int irq, irq_handler_t handler,
* We do this before actually registering it, to make sure that
* a 'real' IRQ doesn't run in parallel with our fake
*/
- if (irqflags & IRQF_DISABLED) {
- unsigned long flags;
+ unsigned long flags;
- local_irq_save(flags);
- handler(irq, dev_id);
- local_irq_restore(flags);
- } else
- handler(irq, dev_id);
+ local_irq_save(flags);
+ handler(irq, dev_id);
+ local_irq_restore(flags);
}
#endif