From 1fd2c10acb7b35d72101a4619ee5b2cddb9efd3a Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Sat, 27 Jul 2024 12:11:02 +0200 Subject: [PATCH] parisc: fix unaligned accesses in BPF There were spurious unaligned access warnings when calling BPF code. Sometimes, the warnings were triggered with any incoming packet, making the machine hard to use. The reason for the warnings is this: on parisc64, pointers to functions are not really pointers to functions, they are pointers to 16-byte descriptor. The first 8 bytes of the descriptor is a pointer to the function and the next 8 bytes of the descriptor is the content of the "dp" register. This descriptor is generated in the function bpf_jit_build_prologue. The problem is that the function bpf_int_jit_compile advertises 4-byte alignment when calling bpf_jit_binary_alloc, bpf_jit_binary_alloc randomizes the returned array and if the array happens to be not aligned on 8-byte boundary, the descriptor generated in bpf_jit_build_prologue is also not aligned and this triggers the unaligned access warning. Fix this by advertising 8-byte alignment on parisc64 when calling bpf_jit_binary_alloc. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Helge Deller --- arch/parisc/net/bpf_jit_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/parisc/net/bpf_jit_core.c b/arch/parisc/net/bpf_jit_core.c index 979f45d4d1fb..06cbcd6fe87b 100644 --- a/arch/parisc/net/bpf_jit_core.c +++ b/arch/parisc/net/bpf_jit_core.c @@ -114,7 +114,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) jit_data->header = bpf_jit_binary_alloc(prog_size + extable_size, &jit_data->image, - sizeof(u32), + sizeof(long), bpf_fill_ill_insns); if (!jit_data->header) { prog = orig_prog;