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authorJames Hogan <james.hogan@imgtec.com>2017-06-29 10:12:34 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-27 15:06:07 -0700
commit62d131ec60cdd8751e40e92b0fb78e30932e6c14 (patch)
tree8b26daf53e68883edf133615a792800c943f8253 /arch
parent4d9f109ff9ca5624e14bbdfbd60b63513123b060 (diff)
downloadlinux-linaro-stable-62d131ec60cdd8751e40e92b0fb78e30932e6c14.tar.gz
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 <james.hogan@imgtec.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16651/ Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/kernel/ptrace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index c95bf18260f8..24c115a0721a 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -927,7 +927,7 @@ asmlinkage void syscall_trace_leave(struct pt_regs *regs)
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);