Commit a1c04bcc authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Daniel Borkmann
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s390/bpf: Land on the next JITed instruction after exception 



Currently we land on the nop, which is unnecessary: we can just as well
begin executing the next instruction. Furthermore, the upcoming arena
support for the loop-based BPF_XCHG implementation will require landing
on an instruction that comes after the loop.

So land on the next JITed instruction, which covers both cases.

Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240701234304.14336-6-iii@linux.ibm.com
parent 89b933a2

arch/s390/net/bpf_jit_comp.c

+4 −3
Original line number Diff line number Diff line
@@ -747,10 +747,11 @@ static int bpf_jit_probe_post(struct bpf_jit *jit, struct bpf_prog *fp, 
			return -1;

		ex->insn = delta;

		/*

		 * Always land on the nop. Note that extable infrastructure

		 * ignores fixup field, it is handled by ex_handler_bpf().

		 * Land on the current instruction. Note that the extable

		 * infrastructure ignores the fixup field; it is handled by

		 * ex_handler_bpf().

		 */

		delta = jit->prg_buf + probe->nop_prg - (u8 *)&ex->fixup;

		delta = jit->prg_buf + jit->prg - (u8 *)&ex->fixup;

		if (WARN_ON_ONCE(delta < INT_MIN || delta > INT_MAX))

			/* JIT bug - landing pad and extable must be close. */

			return -1;