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bpf: Migrate dynptr file to kmalloc_nolock

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Replace bpf_mem_alloc/bpf_mem_free with kmalloc_nolock/kfree_nolock for
bpf_dynptr_file_impl, continuing the migration away from bpf_mem_alloc
now that kmalloc can be used from NMI context.

freader_cleanup() runs before kfree_nolock() while the dynptr still
holds exclusive access, so plain kfree_nolock() is safe — no concurrent
readers can access the object.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260330-kmalloc_special-v2-2-c90403f92ff0@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Mykyta Yatsenko
2026-03-30 15:27:57 -07:00
committed by Alexei Starovoitov
parent 90f51ebff2
commit cc878b4144
1 changed files with 2 additions and 2 deletions
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4
kernel/bpf/helpers.c
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@@ -4565,7 +4565,7 @@ static int make_file_dynptr(struct file *file, u32 flags, bool may_sleep,
return -EINVAL;
}
state = bpf_mem_alloc(&bpf_global_ma, sizeof(struct bpf_dynptr_file_impl));
state = kmalloc_nolock(sizeof(*state), 0, NUMA_NO_NODE);
if (!state) {
bpf_dynptr_set_null(ptr);
return -ENOMEM;
@@ -4597,7 +4597,7 @@ __bpf_kfunc int bpf_dynptr_file_discard(struct bpf_dynptr *dynptr)
return 0;
freader_cleanup(&df->freader);
bpf_mem_free(&bpf_global_ma, df);
kfree_nolock(df);
bpf_dynptr_set_null(ptr);
return 0;
}