6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Song Liu song@kernel.org
[ 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@kernel.org Fixes: 528eb2cb87bc ("s390/bpf: Implement arch_prepare_bpf_trampoline()") Reviewed-by: Ilya Leoshkevich iii@linux.ibm.com Link: https://lore.kernel.org/r/20230919060258.3237176-2-song@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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)