Messages in this thread Patch in this message | | | From | Semen Protsenko <> | Subject | [PATCH] genirq: check irq_ack callback in handle_edge_irq() before calling | Date | Tue, 21 Apr 2015 16:09:12 +0300 |
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Direct calling of .irq_ack callback (from struct irq_chip) leads to NULL pointer dereference in some cases. E.g. this was observed for MAX732X driver on hibernation:
Unable to handle kernel NULL pointer dereference at virtual address 0 Backtrace: (handle_edge_irq) from (resend_irqs) (resend_irqs) from (tasklet_action) (tasklet_action) from (__do_softirq) (__do_softirq) from (run_ksoftirqd) (run_ksoftirqd) from (smpboot_thread_fn) (smpboot_thread_fn) from (kthread) (kthread) from (ret_from_fork)
This patch checks if .irq_ack was set, so in case it wasn't (i.e. it's NULL) we wouldn't have NULL pointer dereference. This check seems to be pretty common in kernel/irq/chip.c, but it was missed for handle_edge_irq() function.
Signed-off-by: Semen Protsenko <semen.protsenko@globallogic.com> --- kernel/irq/chip.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index eb9a4ea..3889b02 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -586,7 +586,8 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc) kstat_incr_irqs_this_cpu(irq, desc); /* Start handling the irq */ - desc->irq_data.chip->irq_ack(&desc->irq_data); + if (desc->irq_data.chip->irq_ack) + desc->irq_data.chip->irq_ack(&desc->irq_data); do { if (unlikely(!desc->action)) { -- 1.7.9.5
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