From 1eeb7407d23300db0b70ef853130e178c992c8cd Mon Sep 17 00:00:00 2001 From: Timothy E Baldwin Date: Mon, 8 Oct 2018 19:26:48 +0100 Subject: [PATCH] ARM: 8802/1: Call syscall_trace_exit even when system call skipped [ Upstream commit f18aef742c8fbd68e280dff0a63ba0ca6ee8ad85 ] On at least x86 and ARM64, and as documented in the ptrace man page a skipped system call will still cause a syscall exit ptrace stop. Previous to this commit 32-bit ARM did not, resulting in strace being confused when seccomp skips system calls. This change also impacts programs that use ptrace to skip system calls. Fixes: ad75b51459ae ("ARM: 7579/1: arch/allow a scno of -1 to not cause a SIGILL") Signed-off-by: Timothy E Baldwin Signed-off-by: Eugene Syromyatnikov Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Eugene Syromyatnikov Signed-off-by: Russell King Signed-off-by: Sasha Levin --- arch/arm/kernel/entry-common.S | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 746565a..0465d65 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -296,16 +296,15 @@ __sys_trace: cmp scno, #-1 @ skip the syscall? bne 2b add sp, sp, #S_OFF @ restore stack - b ret_slow_syscall -__sys_trace_return: - str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 +__sys_trace_return_nosave: + enable_irq_notrace mov r0, sp bl syscall_trace_exit b ret_slow_syscall -__sys_trace_return_nosave: - enable_irq_notrace +__sys_trace_return: + str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 mov r0, sp bl syscall_trace_exit b ret_slow_syscall -- 2.7.4