[RFC 1/6] powerpc/mm/book3s64: unlock RCU before returning from mm_iommu_is_devmem()
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From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Date: 2026-09-28 10:45:05
Also in:
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Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Clang's context analysis reports:
iommu_api.c:380:1: error: __ctx_lock_RCU 'RCU' is not held on every path through here [-Werror,-Wthread-safety-analysis]
mm_iommu_is_devmem() takes the RCU read lock to walk the preregistered
device-memory list. On a match it returned true from inside the loop and
skipped rcu_read_unlock(). Hence fix it.
Fixes: b5952f8125ae ("powerpc/mm/book3s64/iommu: fix some RCU-list locks")
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
---
arch/powerpc/mm/book3s64/iommu_api.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c
index 60d00c9e7f19..56d9aa6cc8e2 100644
--- a/arch/powerpc/mm/book3s64/iommu_api.c
+++ b/arch/powerpc/mm/book3s64/iommu_api.c@@ -356,6 +356,7 @@ bool mm_iommu_is_devmem(struct mm_struct *mm, unsigned long hpa, { struct mm_iommu_table_group_mem_t *mem; unsigned long end; + bool ret = false; rcu_read_lock(); list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
@@ -371,12 +372,13 @@ bool mm_iommu_is_devmem(struct mm_struct *mm, unsigned long hpa, * and the caller needs to distinguish this situation. */ *size = min(1UL << pageshift, end - hpa); - return true; + ret = true; + break; } } rcu_read_unlock(); - return false; + return ret; } EXPORT_SYMBOL_GPL(mm_iommu_is_devmem);
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2.39.5