mirror of https://github.com/torvalds/linux.git
b150654f74
Commit <d74169ceb0d2> ("iommu/vt-d: Allocate DMAR fault interrupts
locally") moved the call to enable_drhd_fault_handling() to a code
path that does not hold any lock while traversing the drhd list. Fix
it by ensuring the dmar_global_lock lock is held when traversing the
drhd list.
Without this fix, the following warning is triggered:
=============================
WARNING: suspicious RCU usage
6.14.0-rc3 #55 Not tainted
-----------------------------
drivers/iommu/intel/dmar.c:2046 RCU-list traversed in non-reader section!!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 1
2 locks held by cpuhp/1/23:
#0: ffffffff84a67c50 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0
#1: ffffffff84a6a380 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0
stack backtrace:
CPU: 1 UID: 0 PID: 23 Comm: cpuhp/1 Not tainted 6.14.0-rc3 #55
Call Trace:
<TASK>
dump_stack_lvl+0xb7/0xd0
lockdep_rcu_suspicious+0x159/0x1f0
? __pfx_enable_drhd_fault_handling+0x10/0x10
enable_drhd_fault_handling+0x151/0x180
cpuhp_invoke_callback+0x1df/0x990
cpuhp_thread_fun+0x1ea/0x2c0
smpboot_thread_fn+0x1f5/0x2e0
? __pfx_smpboot_thread_fn+0x10/0x10
kthread+0x12a/0x2d0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x4a/0x60
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
Holding the lock in enable_drhd_fault_handling() triggers a lockdep splat
about a possible deadlock between dmar_global_lock and cpu_hotplug_lock.
This is avoided by not holding dmar_global_lock when calling
iommu_device_register(), which initiates the device probe process.
Fixes:
|
||
|---|---|---|
| .. | ||
| amd | ||
| arm | ||
| intel | ||
| iommufd | ||
| riscv | ||
| Kconfig | ||
| Makefile | ||
| apple-dart.c | ||
| dma-iommu.c | ||
| dma-iommu.h | ||
| exynos-iommu.c | ||
| fsl_pamu.c | ||
| fsl_pamu.h | ||
| fsl_pamu_domain.c | ||
| fsl_pamu_domain.h | ||
| hyperv-iommu.c | ||
| io-pgfault.c | ||
| io-pgtable-arm-v7s.c | ||
| io-pgtable-arm.c | ||
| io-pgtable-arm.h | ||
| io-pgtable-dart.c | ||
| io-pgtable.c | ||
| iommu-debugfs.c | ||
| iommu-pages.h | ||
| iommu-priv.h | ||
| iommu-sva.c | ||
| iommu-sysfs.c | ||
| iommu-traces.c | ||
| iommu.c | ||
| iova.c | ||
| ipmmu-vmsa.c | ||
| irq_remapping.c | ||
| irq_remapping.h | ||
| msm_iommu.c | ||
| msm_iommu.h | ||
| msm_iommu_hw-8xxx.h | ||
| mtk_iommu.c | ||
| mtk_iommu_v1.c | ||
| of_iommu.c | ||
| omap-iommu-debug.c | ||
| omap-iommu.c | ||
| omap-iommu.h | ||
| omap-iopgtable.h | ||
| rockchip-iommu.c | ||
| s390-iommu.c | ||
| sprd-iommu.c | ||
| sun50i-iommu.c | ||
| tegra-smmu.c | ||
| virtio-iommu.c | ||