4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: James Hogan <[email protected]> commit 4f32a39d49b25eaa66d2420f1f03d371ea4cd906 upstream. The sys_exit trace event takes a single return value for the system call, which MIPS passes the value of the $v0 (result) register, however MIPS returns positive error codes in $v0 with $a3 specifying that $v0 contains an error code. As a result erroring system calls are traced returning positive error numbers that can't always be distinguished from success. Use regs_return_value() to negate the error code if $a3 is set. Fixes: 1d7bf993e073 ("MIPS: ftrace: Add support for syscall tracepoints.") Signed-off-by: James Hogan <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: [email protected] Patchwork: https://patchwork.linux-mips.org/patch/16651/ Acked-by: Steven Rostedt (VMware) <[email protected]> Signed-off-by: Ralf Baechle <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/mips/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -924,7 +924,7 @@ asmlinkage void syscall_trace_leave(stru audit_syscall_exit(regs); if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) - trace_sys_exit(regs, regs->regs[2]); + trace_sys_exit(regs, regs_return_value(regs)); if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall_exit(regs, 0);
