On Friday 26 May 2006 05:24, Jeff Dike wrote:
> We are seeing double ptrace notifications of system call returns on recent
> x86_64 kernels. This breaks UML and at least one other app.
I believe this patch is the correct fix. Can you confirm it works for you?
-Andi
Don't do syscall exit tracing twice
int_ret_from_syscall already does syscall exit tracing, so
no need to do it again in the caller.
This caused problems for UML and some other special programs doing
syscall interception.
Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>
Index: linux/arch/x86_64/kernel/entry.S
===================================================================
--- linux.orig/arch/x86_64/kernel/entry.S
+++ linux/arch/x86_64/kernel/entry.S
@@ -282,12 +282,7 @@ tracesys:
ja 1f
movq %r10,%rcx /* fixup for C */
call *sys_call_table(,%rax,8)
- movq %rax,RAX-ARGOFFSET(%rsp)
-1: SAVE_REST
- movq %rsp,%rdi
- call syscall_trace_leave
- RESTORE_TOP_OF_STACK %rbx
- RESTORE_REST
+1: movq %rax,RAX-ARGOFFSET(%rsp)
/* Use IRET because user could have changed frame */
jmp int_ret_from_sys_call
CFI_ENDPROC
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