Commit a304e1b82808904c561b7b149b467e338c53fcce
Committed by
Linus Torvalds
Linus Torvalds
1 parent
f9e4acf3be
Exists in
master
and in
4 other branches
[PATCH] Debug shared irqs
Drivers registering IRQ handlers with SA_SHIRQ really ought to be able to handle an interrupt happening before request_irq() returns. They also ought to be able to handle an interrupt happening during the start of their call to free_irq(). Let's test that hypothesis.... [bunk@stusta.de: Kconfig fixes] Signed-off-by: David Woodhouse <dwmw2@infradead.org> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Showing 2 changed files with 42 additions and 0 deletions Side-by-side Diff
kernel/irq/manage.c
| ... | ... | @@ -357,6 +357,7 @@ |
| 357 | 357 | struct irq_desc *desc; |
| 358 | 358 | struct irqaction **p; |
| 359 | 359 | unsigned long flags; |
| 360 | + irqreturn_t (*handler)(int, void *) = NULL; | |
| 360 | 361 | |
| 361 | 362 | WARN_ON(in_interrupt()); |
| 362 | 363 | if (irq >= NR_IRQS) |
| ... | ... | @@ -396,6 +397,8 @@ |
| 396 | 397 | |
| 397 | 398 | /* Make sure it's not being used on another CPU */ |
| 398 | 399 | synchronize_irq(irq); |
| 400 | + if (action->flags & IRQF_SHARED) | |
| 401 | + handler = action->handler; | |
| 399 | 402 | kfree(action); |
| 400 | 403 | return; |
| 401 | 404 | } |
| ... | ... | @@ -403,6 +406,17 @@ |
| 403 | 406 | spin_unlock_irqrestore(&desc->lock, flags); |
| 404 | 407 | return; |
| 405 | 408 | } |
| 409 | +#ifdef CONFIG_DEBUG_SHIRQ | |
| 410 | + if (handler) { | |
| 411 | + /* | |
| 412 | + * It's a shared IRQ -- the driver ought to be prepared for it | |
| 413 | + * to happen even now it's being freed, so let's make sure.... | |
| 414 | + * We do this after actually deregistering it, to make sure that | |
| 415 | + * a 'real' IRQ doesn't run in parallel with our fake | |
| 416 | + */ | |
| 417 | + handler(irq, dev_id); | |
| 418 | + } | |
| 419 | +#endif | |
| 406 | 420 | } |
| 407 | 421 | EXPORT_SYMBOL(free_irq); |
| 408 | 422 | |
| ... | ... | @@ -474,6 +488,25 @@ |
| 474 | 488 | action->dev_id = dev_id; |
| 475 | 489 | |
| 476 | 490 | select_smp_affinity(irq); |
| 491 | + | |
| 492 | +#ifdef CONFIG_DEBUG_SHIRQ | |
| 493 | + if (irqflags & IRQF_SHARED) { | |
| 494 | + /* | |
| 495 | + * It's a shared IRQ -- the driver ought to be prepared for it | |
| 496 | + * to happen immediately, so let's make sure.... | |
| 497 | + * We do this before actually registering it, to make sure that | |
| 498 | + * a 'real' IRQ doesn't run in parallel with our fake | |
| 499 | + */ | |
| 500 | + if (irqflags & IRQF_DISABLED) { | |
| 501 | + unsigned long flags; | |
| 502 | + | |
| 503 | + local_irq_save(flags); | |
| 504 | + handler(irq, dev_id); | |
| 505 | + local_irq_restore(flags); | |
| 506 | + } else | |
| 507 | + handler(irq, dev_id); | |
| 508 | + } | |
| 509 | +#endif | |
| 477 | 510 | |
| 478 | 511 | retval = setup_irq(irq, action); |
| 479 | 512 | if (retval) |
lib/Kconfig.debug
| ... | ... | @@ -77,6 +77,15 @@ |
| 77 | 77 | Say Y here if you are developing drivers or trying to debug and |
| 78 | 78 | identify kernel problems. |
| 79 | 79 | |
| 80 | +config DEBUG_SHIRQ | |
| 81 | + bool "Debug shared IRQ handlers" | |
| 82 | + depends on DEBUG_KERNEL && GENERIC_HARDIRQS | |
| 83 | + help | |
| 84 | + Enable this to generate a spurious interrupt as soon as a shared | |
| 85 | + interrupt handler is registered, and just before one is deregistered. | |
| 86 | + Drivers ought to be able to handle interrupts coming in at those | |
| 87 | + points; some don't and need to be caught. | |
| 88 | + | |
| 80 | 89 | config LOG_BUF_SHIFT |
| 81 | 90 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL |
| 82 | 91 | range 12 21 |