From: Roland McGrath Date: Mon, 17 Mar 2008 04:57:41 +0000 (-0700) Subject: x86: ia32 ptrace vs -ENOSYS X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=8ab32bb89b5b9bf06147c31947eba65f0f21c3c0;p=openwrt%2Fstaging%2Fblogic.git x86: ia32 ptrace vs -ENOSYS When we're stopped at syscall entry tracing, ptrace can change the %eax value from -ENOSYS to something else. If no system call is actually made because the syscall number (now in orig_eax) is bad, then the %eax value set by ptrace should be returned to the user. But, instead it gets reset to -ENOSYS again. This is a regression from the native 32-bit kernel. This change fixes it by leaving the return value alone after entry tracing. Signed-off-by: Roland McGrath Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 8022d3c695c0..30f492934f23 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -325,7 +325,7 @@ ENTRY(ia32_syscall) jnz ia32_tracesys ia32_do_syscall: cmpl $(IA32_NR_syscalls-1),%eax - ja ia32_badsys + ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */ IA32_ARG_FIXUP call *ia32_sys_call_table(,%rax,8) # xxx: rip relative ia32_sysret: @@ -335,7 +335,7 @@ ia32_sysret: ia32_tracesys: SAVE_REST CLEAR_RREGS - movq $-ENOSYS,RAX(%rsp) /* really needed? */ + movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */