From: H. Peter Anvin Date: Mon, 10 May 2021 18:53:15 +0000 (-0700) Subject: x86/regs: Syscall_get_nr() returns -1 for a non-system call X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9ddcb87b9218dec760e8d8a780bc8ad514c3d36a;p=linux.git x86/regs: Syscall_get_nr() returns -1 for a non-system call syscall_get_nr() is defined to return -1 for a non-system call or a ptrace/seccomp restart; not just any arbitrary number. See comment in for the official definition of this function. Signed-off-by: H. Peter Anvin Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20210510185316.3307264-7-hpa@zytor.com --- diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 87a4143aa7d7c..4c208ea3bd9f3 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -911,7 +911,7 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value) * syscall with TS_COMPAT still set. */ regs->orig_ax = value; - if (syscall_get_nr(child, regs) >= 0) + if (syscall_get_nr(child, regs) != -1) child->thread_info.status |= TS_I386_REGS_POKED; break; diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index a06cb107c0e88..e12779a2714dc 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -713,7 +713,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs) save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL); /* Are we from a system call? */ - if (syscall_get_nr(current, regs) >= 0) { + if (syscall_get_nr(current, regs) != -1) { /* If so, check system call restarting.. */ switch (syscall_get_error(current, regs)) { case -ERESTART_RESTARTBLOCK: @@ -793,7 +793,7 @@ void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) } /* Did we come from a system call? */ - if (syscall_get_nr(current, regs) >= 0) { + if (syscall_get_nr(current, regs) != -1) { /* Restart the system call - no handlers present */ switch (syscall_get_error(current, regs)) { case -ERESTARTNOHAND: