diff options
| author | Qian Cai <cai@lca.pw> | 2020-05-10 01:15:59 -0400 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-01-31 22:35:49 +1100 |
| commit | b5952f8125ae512420d5fc569adce591bea73bf5 (patch) | |
| tree | b3311d427b51935251f2e1eedcc8ddabcd2ac841 /arch/powerpc/mm | |
| parent | c9790fb5df461c91d3fff1d864c1acb8baf5ad5c (diff) | |
powerpc/mm/book3s64/iommu: fix some RCU-list locks
It is safe to traverse mm->context.iommu_group_mem_list with either
mem_list_mutex or the RCU read lock held. Silence a few RCU-list false
positive warnings and fix a few missing RCU read locks.
arch/powerpc/mm/book3s64/iommu_api.c:330 RCU-list traversed in non-reader section!!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
2 locks held by qemu-kvm/4305:
#0: c000000bc3fe4d68 (&container->lock){+.+.}-{3:3}, at: tce_iommu_ioctl.part.9+0xc7c/0x1870 [vfio_iommu_spapr_tce]
#1: c000000001501910 (mem_list_mutex){+.+.}-{3:3}, at: mm_iommu_get+0x50/0x190
====
arch/powerpc/mm/book3s64/iommu_api.c:132 RCU-list traversed in non-reader section!!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
2 locks held by qemu-kvm/4305:
#0: c000000bc3fe4d68 (&container->lock){+.+.}-{3:3}, at: tce_iommu_ioctl.part.9+0xc7c/0x1870 [vfio_iommu_spapr_tce]
#1: c000000001501910 (mem_list_mutex){+.+.}-{3:3}, at: mm_iommu_do_alloc+0x120/0x5f0
====
arch/powerpc/mm/book3s64/iommu_api.c:292 RCU-list traversed in non-reader section!!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
2 locks held by qemu-kvm/4312:
#0: c000000ecafe23c8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0xdc/0x950 [kvm]
#1: c000000045e6c468 (&kvm->srcu){....}-{0:0}, at: kvmppc_h_put_tce+0x88/0x340 [kvm]
====
arch/powerpc/mm/book3s64/iommu_api.c:424 RCU-list traversed in non-reader section!!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
2 locks held by qemu-kvm/4312:
#0: c000000ecafe23c8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0xdc/0x950 [kvm]
#1: c000000045e6c468 (&kvm->srcu){....}-{0:0}, at: kvmppc_h_put_tce+0x88/0x340 [kvm]
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200510051559.1959-1-cai@lca.pw
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/book3s64/iommu_api.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c index 685d7bb3d26f..cd18e94d0843 100644 --- a/arch/powerpc/mm/book3s64/iommu_api.c +++ b/arch/powerpc/mm/book3s64/iommu_api.c @@ -129,7 +129,8 @@ good_exit: mutex_lock(&mem_list_mutex); - list_for_each_entry_rcu(mem2, &mm->context.iommu_group_mem_list, next) { + list_for_each_entry_rcu(mem2, &mm->context.iommu_group_mem_list, next, + lockdep_is_held(&mem_list_mutex)) { /* Overlap? */ if ((mem2->ua < (ua + (entries << PAGE_SHIFT))) && (ua < (mem2->ua + @@ -289,6 +290,7 @@ struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm, { struct mm_iommu_table_group_mem_t *mem, *ret = NULL; + rcu_read_lock(); list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) { if ((mem->ua <= ua) && (ua + size <= mem->ua + @@ -297,6 +299,7 @@ struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm, break; } } + rcu_read_unlock(); return ret; } @@ -327,7 +330,8 @@ struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm, mutex_lock(&mem_list_mutex); - list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) { + list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next, + lockdep_is_held(&mem_list_mutex)) { if ((mem->ua == ua) && (mem->entries == entries)) { ret = mem; ++mem->used; @@ -421,6 +425,7 @@ bool mm_iommu_is_devmem(struct mm_struct *mm, unsigned long hpa, struct mm_iommu_table_group_mem_t *mem; unsigned long end; + rcu_read_lock(); list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) { if (mem->dev_hpa == MM_IOMMU_TABLE_INVALID_HPA) continue; @@ -437,6 +442,7 @@ bool mm_iommu_is_devmem(struct mm_struct *mm, unsigned long hpa, return true; } } + rcu_read_unlock(); return false; } |