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authorJoerg Roedel <jroedel@suse.de>2017-07-26 14:17:55 +0200
committerJoerg Roedel <jroedel@suse.de>2017-07-26 15:39:14 +0200
commit74ddda71f44c84af62f736a77fb9fcebe5bb436a (patch)
treee19eadd2ac8823acde106fa91fd7962f28f92d6b
parentefe6f241602cb61466895f6816b8ea6b90f04d4e (diff)
downloadlinux-stericsson-74ddda71f44c84af62f736a77fb9fcebe5bb436a.tar.gz
iommu/amd: Fix schedule-while-atomic BUG in initialization code
The register_syscore_ops() function takes a mutex and might sleep. In the IOMMU initialization code it is invoked during irq-remapping setup already, where irqs are disabled. This causes a schedule-while-atomic bug: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747 in_atomic(): 0, irqs_disabled(): 1, pid: 1, name: swapper/0 no locks held by swapper/0/1. irq event stamp: 304 hardirqs last enabled at (303): [<ffffffff818a87b6>] _raw_spin_unlock_irqrestore+0x36/0x60 hardirqs last disabled at (304): [<ffffffff8235d440>] enable_IR_x2apic+0x79/0x196 softirqs last enabled at (36): [<ffffffff818ae75f>] __do_softirq+0x35f/0x4ec softirqs last disabled at (31): [<ffffffff810c1955>] irq_exit+0x105/0x120 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.13.0-rc2.1.el7a.test.x86_64.debug #1 Hardware name: PowerEdge C6145 /040N24, BIOS 3.5.0 10/28/2014 Call Trace: dump_stack+0x85/0xca ___might_sleep+0x22a/0x260 __might_sleep+0x4a/0x80 __mutex_lock+0x58/0x960 ? iommu_completion_wait.part.17+0xb5/0x160 ? register_syscore_ops+0x1d/0x70 ? iommu_flush_all_caches+0x120/0x150 mutex_lock_nested+0x1b/0x20 register_syscore_ops+0x1d/0x70 state_next+0x119/0x910 iommu_go_to_state+0x29/0x30 amd_iommu_enable+0x13/0x23 Fix it by moving the register_syscore_ops() call to the next initialization step, which runs with irqs enabled. Reported-by: Artem Savkov <asavkov@redhat.com> Tested-by: Artem Savkov <asavkov@redhat.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Fixes: 2c0ae1720c09 ('iommu/amd: Convert iommu initialization to state machine') Signed-off-by: Joerg Roedel <jroedel@suse.de>
-rw-r--r--drivers/iommu/amd_iommu_init.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 5cc597b383c7..372303700566 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -2440,11 +2440,11 @@ static int __init state_next(void)
break;
case IOMMU_ACPI_FINISHED:
early_enable_iommus();
- register_syscore_ops(&amd_iommu_syscore_ops);
x86_platform.iommu_shutdown = disable_iommus;
init_state = IOMMU_ENABLED;
break;
case IOMMU_ENABLED:
+ register_syscore_ops(&amd_iommu_syscore_ops);
ret = amd_iommu_init_pci();
init_state = ret ? IOMMU_INIT_ERROR : IOMMU_PCI_INIT;
enable_iommus_v2();