summaryrefslogtreecommitdiff
path: root/kernel/irq/msi.c
diff options
context:
space:
mode:
authorMarc Zyngier <marc.zyngier@arm.com>2015-01-26 19:10:19 +0000
committerThomas Gleixner <tglx@linutronix.de>2015-04-08 23:28:28 +0200
commitfe0c52fc003bc046380e52fe6799c96d770770cc (patch)
treec9f6d9550edb84d205b0beb3aab8269e355ff0a8 /kernel/irq/msi.c
parent462b69b1e43ceccab68a47d65b1e46520cd0fdc0 (diff)
genirq: MSI: Fix freeing of unallocated MSI
While debugging an unrelated issue with the GICv3 ITS driver, the following trace triggered: WARNING: CPU: 1 PID: 1 at kernel/irq/irqdomain.c:1121 irq_domain_free_irqs+0x160/0x17c() NULL pointer, cannot free irq Modules linked in: CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 3.19.0-rc6+ #3690 Hardware name: FVP Base (DT) Call trace: [<ffffffc000089398>] dump_backtrace+0x0/0x13c [<ffffffc0000894e4>] show_stack+0x10/0x1c [<ffffffc00066d134>] dump_stack+0x74/0x94 [<ffffffc0000a92f8>] warn_slowpath_common+0x9c/0xd4 [<ffffffc0000a938c>] warn_slowpath_fmt+0x5c/0x80 [<ffffffc0000ee04c>] irq_domain_free_irqs+0x15c/0x17c [<ffffffc0000ef918>] msi_domain_free_irqs+0x58/0x74 [<ffffffc000386f58>] free_msi_irqs+0xb4/0x1c0 // The msi_prepare callback fails here [<ffffffc0003872c0>] pci_enable_msix+0x25c/0x3d4 [<ffffffc00038746c>] pci_enable_msix_range+0x34/0x80 [<ffffffc0003924ac>] vp_try_to_find_vqs+0xec/0x528 [<ffffffc000392954>] vp_find_vqs+0x6c/0xa8 [<ffffffc0003ee2a8>] init_vq+0x120/0x248 [<ffffffc0003eefb0>] virtblk_probe+0xb0/0x6bc [<ffffffc00038fc34>] virtio_dev_probe+0x17c/0x214 [<ffffffc0003d4a04>] driver_probe_device+0x7c/0x23c [<ffffffc0003d4cb0>] __driver_attach+0x98/0xa0 [<ffffffc0003d2c60>] bus_for_each_dev+0x60/0xb4 [<ffffffc0003d455c>] driver_attach+0x1c/0x28 [<ffffffc0003d41b0>] bus_add_driver+0x150/0x208 [<ffffffc0003d54c0>] driver_register+0x64/0x130 [<ffffffc00038f9e8>] register_virtio_driver+0x24/0x68 [<ffffffc00091320c>] init+0x70/0xac [<ffffffc0000828f0>] do_one_initcall+0x94/0x1d0 [<ffffffc0008e9b00>] kernel_init_freeable+0x144/0x1e4 [<ffffffc00066a434>] kernel_init+0xc/0xd8 ---[ end trace f9ee562a77cc7bae ]--- The ITS msi_prepare callback having failed, we end-up trying to free MSIs that have never been allocated. Oddly enough, the kernel is pretty upset about it. It turns out that this behaviour was expected before the MSI domain was introduced (and dealt with in arch_teardown_msi_irqs). The obvious fix is to detect this early enough and bail out. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com> Link: http://lkml.kernel.org/r/1422299419-6051-1-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/irq/msi.c')
-rw-r--r--kernel/irq/msi.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 3e18163f336f..474de5cb394d 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -310,8 +310,15 @@ void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
struct msi_desc *desc;
for_each_msi_entry(desc, dev) {
- irq_domain_free_irqs(desc->irq, desc->nvec_used);
- desc->irq = 0;
+ /*
+ * We might have failed to allocate an MSI early
+ * enough that there is no IRQ associated to this
+ * entry. If that's the case, don't do anything.
+ */
+ if (desc->irq) {
+ irq_domain_free_irqs(desc->irq, desc->nvec_used);
+ desc->irq = 0;
+ }
}
}