diff options
authorJames Hogan <>2017-06-29 10:12:34 +0100
committerGreg Kroah-Hartman <>2017-07-27 15:08:04 -0700
commit02131aea6bd4d7a1414333160124b6a078b262fe (patch)
parentf39f3b5d8260de549887f127ac5e99f0931b4990 (diff)
MIPS: Negate error syscall return in trace
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 <> Cc: Steven Rostedt <> Cc: Ingo Molnar <> Cc: Patchwork: Acked-by: Steven Rostedt (VMware) <> Signed-off-by: Ralf Baechle <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index bf83dc1eecfb..3de026034c35 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -924,7 +924,7 @@ asmlinkage void syscall_trace_leave(struct pt_regs *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);