The patch titled genirq: warn when IRQF_DISABLED may be ignored has been added to the -mm tree. Its filename is genirq-warn-when-irqf_disabled-may-be-ignored.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: genirq: warn when IRQF_DISABLED may be ignored From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx> We periodically waste time tracking down problems from the genirq framework not respecting IRQF_DISABLED for some shared IRQ cases. Linus views this as "will not fix", but we're still left with the bugs caused by this misbehavior. This patch adds a nag message in request_irq(), so that drivers can fix their IRQ handlers to avoid this problem. Note that developers will never see the relevant bugs when they run with LOCKDEP, so it's no wonder these bugs are hard to find. (That also means LOCKDEP is overlooking some IRQ-related bugs involving IRQ handlers that don't set IRQF_DISABLED...) Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/irq/manage.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff -puN kernel/irq/manage.c~genirq-warn-when-irqf_disabled-may-be-ignored kernel/irq/manage.c --- a/kernel/irq/manage.c~genirq-warn-when-irqf_disabled-may-be-ignored +++ a/kernel/irq/manage.c @@ -635,6 +635,18 @@ int request_irq(unsigned int irq, irq_ha struct irq_desc *desc; int retval; + /* + * handle_IRQ_event() always ignores IRQF_DISABLED except for + * the _first_ irqaction (sigh). That can cause oopsing, but + * the behavior is classified as "will not fix" so we need to + * start nudging drivers away from using that idiom. + */ + if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) + == (IRQF_SHARED|IRQF_DISABLED)) + pr_warning("IRQ %d/%s: IRQF_DISABLED is not " + "guaranteed on shared IRQs\n", + irq, devname); + #ifdef CONFIG_LOCKDEP /* * Lockdep wants atomic interrupt handlers: _ Patches currently in -mm which might be from dbrownell@xxxxxxxxxxxxxxxxxxxxx are linux-next.patch spi_gpio-driver.patch spi_gpio-driver-cleanups.patch rtc-ds1307-remove-legacy-probe-checks.patch genirq-warn-when-irqf_disabled-may-be-ignored.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html