Commit d83ee6e3 authored Jul 10, 2020 by Will Deacon

arm64: ptrace: Use NO_SYSCALL instead of -1 in syscall_trace_enter()

Setting a system call number of -1 is special, as it indicates that the
current system call should be skipped.

Use NO_SYSCALL instead of -1 when checking for this scenario, which is
different from the -1 returned due to a seccomp failure.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Keno Fischer <keno@juliacomputing.com>
Cc: Luis Machado <luis.machado@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>

parent 139dbe5d

arch/arm64/kernel/ptrace.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1856,12 +1856,12 @@ int syscall_trace_enter(struct pt_regs *regs)
		if (flags & (_TIF_SYSCALL_EMU \| _TIF_SYSCALL_TRACE)) {
		tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
		if (!in_syscall(regs) \|\| (flags & _TIF_SYSCALL_EMU))
		return -1;
		return NO_SYSCALL;
		}

		/* Do the secure computing after ptrace; failures should be fast. */
		if (secure_computing() == -1)
		return -1;
		return NO_SYSCALL;

		if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
		trace_sys_enter(regs, regs->syscallno);

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