iommu/arm-smmu: Defer probe of clients after smmu device bound

stable inclusion
from stable-v6.6.66
commit 4a9485918a042e3114890dfbe19839a1897f8b2c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IBLUBO

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4a9485918a042e3114890dfbe19839a1897f8b2c



--------------------------------

Null pointer dereference occurs due to a race between smmu
driver probe and client driver probe, when of_dma_configure()
for client is called after the iommu_device_register() for smmu driver
probe has executed but before the driver_bound() for smmu driver
has been called.

Following is how the race occurs:

T1:Smmu device probe		T2: Client device probe

really_probe()
arm_smmu_device_probe()
iommu_device_register()
					really_probe()
					platform_dma_configure()
					of_dma_configure()
					of_dma_configure_id()
					of_iommu_configure()
					iommu_probe_device()
					iommu_init_device()
					arm_smmu_probe_device()
					arm_smmu_get_by_fwnode()
						driver_find_device_by_fwnode()
						driver_find_device()
						next_device()
						klist_next()
						    /* null ptr
						       assigned to smmu */
					/* null ptr dereference
					   while smmu->streamid_mask */
driver_bound()
	klist_add_tail()

When this null smmu pointer is dereferenced later in
arm_smmu_probe_device, the device crashes.

Fix this by deferring the probe of the client device
until the smmu device has bound to the arm smmu driver.

Fixes: 021bb842 ("iommu/arm-smmu: Wire up generic configuration support")
Cc: stable@vger.kernel.org
Co-developed-by: Prakash Gupta <quic_guptap@quicinc.com>
Signed-off-by: Prakash Gupta <quic_guptap@quicinc.com>
Signed-off-by: Pratyush Brahma <quic_pbrahma@quicinc.com>
Link: https://lore.kernel.org/r/20241004090428.2035-1-quic_pbrahma@quicinc.com


[will: Add comment]
Signed-off-by: Will Deacon <will@kernel.org>
Conflicts:
drivers/iommu/arm/arm-smmu/arm-smmu.c
Signed-off-by: cuiyudong <cuiyudong@kylinos.cn>