Commit 4fc49b51 authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Andrii Nakryiko
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selftests/bpf: Fix an endianness issue in bpf_syscall_macro test 



bpf_syscall_macro reads a long argument into an int variable, which
produces a wrong value on big-endian systems. Fix by reading the
argument into an intermediate long variable first.

Fixes: 77fc0330 ("selftests/bpf: Add a test to confirm PT_REGS_PARM4_SYSCALL")
Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209021745.2215452-2-iii@linux.ibm.com
parent cca62426

tools/testing/selftests/bpf/progs/bpf_syscall_macro.c

+4 −1
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ int BPF_KPROBE(handle_sys_prctl) 
{

	struct pt_regs *real_regs;

	pid_t pid = bpf_get_current_pid_tgid() >> 32;

	unsigned long tmp;



	if (pid != filter_pid)

		return 0;
@@ -35,7 +36,9 @@ int BPF_KPROBE(handle_sys_prctl) 
	real_regs = (struct pt_regs *)PT_REGS_PARM1(ctx);



	/* test for PT_REGS_PARM */

	bpf_probe_read_kernel(&arg1, sizeof(arg1), &PT_REGS_PARM1_SYSCALL(real_regs));



	bpf_probe_read_kernel(&tmp, sizeof(tmp), &PT_REGS_PARM1_SYSCALL(real_regs));

	arg1 = tmp;

	bpf_probe_read_kernel(&arg2, sizeof(arg2), &PT_REGS_PARM2_SYSCALL(real_regs));

	bpf_probe_read_kernel(&arg3, sizeof(arg3), &PT_REGS_PARM3_SYSCALL(real_regs));

	bpf_probe_read_kernel(&arg4_cx, sizeof(arg4_cx), &PT_REGS_PARM4(real_regs));