From: Jouni Malinen j@w1.fi
[ Upstream commit bebe4681d0e7e1be2608282dc86645728bc7f623 ]
The conversion of UML to use epoll based IRQ controller claimed that clone_one_chan() can safely call um_free_irq() while starting to ignore the delay_free_irq parameter that explicitly noted that the IRQ cannot be freed because this is being called from chan_interrupt(). This resulted in free_irq() getting called in interrupt context ("Trying to free IRQ 6 from IRQ context!").
Fix this by restoring previously used delay_free_irq processing.
Fixes: ff6a17989c08 ("Epoll based IRQ controller") Signed-off-by: Jouni Malinen j@w1.fi Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: Sasha Levin sashal@kernel.org --- arch/um/drivers/chan_kern.c | 52 +++++++++++++++++++++++++++++++------ arch/um/kernel/irq.c | 4 +++ 2 files changed, 48 insertions(+), 8 deletions(-)
diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c index 05588f9466c7f..13ba195f9c9c8 100644 --- a/arch/um/drivers/chan_kern.c +++ b/arch/um/drivers/chan_kern.c @@ -171,19 +171,55 @@ int enable_chan(struct line *line) return err; }
+/* Items are added in IRQ context, when free_irq can't be called, and + * removed in process context, when it can. + * This handles interrupt sources which disappear, and which need to + * be permanently disabled. This is discovered in IRQ context, but + * the freeing of the IRQ must be done later. + */ +static DEFINE_SPINLOCK(irqs_to_free_lock); +static LIST_HEAD(irqs_to_free); + +void free_irqs(void) +{ + struct chan *chan; + LIST_HEAD(list); + struct list_head *ele; + unsigned long flags; + + spin_lock_irqsave(&irqs_to_free_lock, flags); + list_splice_init(&irqs_to_free, &list); + spin_unlock_irqrestore(&irqs_to_free_lock, flags); + + list_for_each(ele, &list) { + chan = list_entry(ele, struct chan, free_list); + + if (chan->input && chan->enabled) + um_free_irq(chan->line->driver->read_irq, chan); + if (chan->output && chan->enabled) + um_free_irq(chan->line->driver->write_irq, chan); + chan->enabled = 0; + } +} + static void close_one_chan(struct chan *chan, int delay_free_irq) { + unsigned long flags; + if (!chan->opened) return;
- /* we can safely call free now - it will be marked - * as free and freed once the IRQ stopped processing - */ - if (chan->input && chan->enabled) - um_free_irq(chan->line->driver->read_irq, chan); - if (chan->output && chan->enabled) - um_free_irq(chan->line->driver->write_irq, chan); - chan->enabled = 0; + if (delay_free_irq) { + spin_lock_irqsave(&irqs_to_free_lock, flags); + list_add(&chan->free_list, &irqs_to_free); + spin_unlock_irqrestore(&irqs_to_free_lock, flags); + } else { + if (chan->input && chan->enabled) + um_free_irq(chan->line->driver->read_irq, chan); + if (chan->output && chan->enabled) + um_free_irq(chan->line->driver->write_irq, chan); + chan->enabled = 0; + } if (chan->ops->close != NULL) (*chan->ops->close)(chan->fd, chan->data);
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c index 6b7f3827d6e4a..2753718d31b9d 100644 --- a/arch/um/kernel/irq.c +++ b/arch/um/kernel/irq.c @@ -21,6 +21,8 @@ #include <irq_user.h>
+extern void free_irqs(void); + /* When epoll triggers we do not know why it did so * we can also have different IRQs for read and write. * This is why we keep a small irq_fd array for each fd - @@ -100,6 +102,8 @@ void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs) } } } + + free_irqs(); }
static int assign_epoll_events_to_irq(struct irq_entry *irq_entry)