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I'm not sure I understand the issue, could you provide more details? thanks, jirka > > Found by cocci: > kernel/bpf/arena.c:245:6-25: WARNING: atomic_dec_and_test variation before object free at line 249. > > Fixes: b90d77e5fd78 ("bpf: Fix remap of arena.") > Reported-by: kernel test robot > Closes: https://lore.kernel.org/oe-kbuild-all/202412292037.LXlYSHKl-lkp@intel.com/ > Signed-off-by: Pei Xiao > --- > kernel/bpf/arena.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c > index 945a5680f6a5..8caf56a308d9 100644 > --- a/kernel/bpf/arena.c > +++ b/kernel/bpf/arena.c > @@ -218,7 +218,7 @@ static u64 arena_map_mem_usage(const struct bpf_map *map) > struct vma_list { > struct vm_area_struct *vma; > struct list_head head; > - atomic_t mmap_count; > + refcount_t mmap_count; > }; > > static int remember_vma(struct bpf_arena *arena, struct vm_area_struct *vma) > @@ -228,7 +228,7 @@ static int remember_vma(struct bpf_arena *arena, struct vm_area_struct *vma) > vml = kmalloc(sizeof(*vml), GFP_KERNEL); > if (!vml) > return -ENOMEM; > - atomic_set(&vml->mmap_count, 1); > + refcount_set(&vml->mmap_count, 1); > vma->vm_private_data = vml; > vml->vma = vma; > list_add(&vml->head, &arena->vma_list); > @@ -239,7 +239,7 @@ static void arena_vm_open(struct vm_area_struct *vma) > { > struct vma_list *vml = vma->vm_private_data; > > - atomic_inc(&vml->mmap_count); > + refcount_inc(&vml->mmap_count); > } > > static void arena_vm_close(struct vm_area_struct *vma) > @@ -248,7 +248,7 @@ static void arena_vm_close(struct vm_area_struct *vma) > struct bpf_arena *arena = container_of(map, struct bpf_arena, map); > struct vma_list *vml = vma->vm_private_data; > > - if (!atomic_dec_and_test(&vml->mmap_count)) > + if (!refcount_dec_and_test(&vml->mmap_count)) > return; > guard(mutex)(&arena->lock); > /* update link list under lock */ > -- > 2.25.1 > >