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bpf: Fix percpu address space issues

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In arraymap.c:

In bpf_array_map_seq_start() and bpf_array_map_seq_next()
cast return values from the __percpu address space to
the generic address space via uintptr_t [1].

Correct the declaration of pptr pointer in __bpf_array_map_seq_show()
to void __percpu * and cast the value from the generic address
space to the __percpu address space via uintptr_t [1].

In hashtab.c:

Assign the return value from bpf_mem_cache_alloc() to void pointer
and cast the value to void __percpu ** (void pointer to percpu void
pointer) before dereferencing.

In memalloc.c:

Explicitly declare __percpu variables.

Cast obj to void __percpu **.

In helpers.c:

Cast ptr in BPF_CALL_1 and BPF_CALL_2 from generic address space
to __percpu address space via const uintptr_t [1].

Found by GCC's named address space checks.

There were no changes in the resulting object files.

[1] https://sparse.docs.kernel.org/en/latest/annotations.html#address-space-name

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240811161414.56744-1-ubizjak@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Uros Bizjak
2024-08-11 18:13:33 +02:00
committed by Alexei Starovoitov
parent 5148f19ac4
commit 6d641ca50d
4 changed files with 17 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
kernel/bpf/arraymap.c
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@@ -600,7 +600,7 @@ static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
array = container_of(map, struct bpf_array, map);
index = info->index & array->index_mask;
if (info->percpu_value_buf)
return array->pptrs[index];
return (void *)(uintptr_t)array->pptrs[index];
return array_map_elem_ptr(array, index);
}
@@ -619,7 +619,7 @@ static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
array = container_of(map, struct bpf_array, map);
index = info->index & array->index_mask;
if (info->percpu_value_buf)
return array->pptrs[index];
return (void *)(uintptr_t)array->pptrs[index];
return array_map_elem_ptr(array, index);
}
@@ -632,7 +632,7 @@ static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
struct bpf_iter_meta meta;
struct bpf_prog *prog;
int off = 0, cpu = 0;
void __percpu **pptr;
void __percpu *pptr;
u32 size;
meta.seq = seq;
@@ -648,7 +648,7 @@ static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
if (!info->percpu_value_buf) {
ctx.value = v;
} else {
pptr = v;
pptr = (void __percpu *)(uintptr_t)v;
size = array->elem_size;
for_each_possible_cpu(cpu) {
copy_map_value_long(map, info->percpu_value_buf + off,