6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Song Liu <song@xxxxxxxxxx>
[ Upstream commit cf094baa3e0f19f1f80ceaf205c80402b024386c ]
arch_prepare_bpf_trampoline() for s390 currently returns 0 on success. This
is not a problem for regular trampoline. However, struct_ops relies on the
return value to advance "image" pointer:
bpf_struct_ops_map_update_elem() {
...
for_each_member(i, t, member) {
...
err = bpf_struct_ops_prepare_trampoline();
...
image += err;
}
}
When arch_prepare_bpf_trampoline returns 0 on success, all members of the
struct_ops will point to the same trampoline (the last one).
Fix this by returning the program size in arch_prepare_bpf_trampoline (on
success). This is the same behavior as other architectures.
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Fixes: 528eb2cb87bc ("s390/bpf: Implement arch_prepare_bpf_trampoline()")
Reviewed-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230919060258.3237176-2-song@xxxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/s390/net/bpf_jit_comp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index de2fb12120d2e..2861e3360affc 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -2513,7 +2513,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
return -E2BIG;
}
- return ret;
+ return tjit.common.prg;
}
bool bpf_jit_supports_subprog_tailcalls(void)
--
2.40.1
