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SubjectRe: [tip:x86/urgent] i386/audit: stop scribbling on the stack frame
On Fri, 24 Oct 2014, tip-bot for Eric Paris wrote:
> sysenter_audit:
> testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
> jnz syscall_trace_entry
> - addl $4,%esp
> - CFI_ADJUST_CFA_OFFSET -4
> - movl %esi,4(%esp) /* 5th arg: 4th syscall arg */
> - movl %edx,(%esp) /* 4th arg: 3rd syscall arg */
> - /* %ecx already in %ecx 3rd arg: 2nd syscall arg */
> - movl %ebx,%edx /* 2nd arg: 1st syscall arg */
> - /* %eax already in %eax 1st arg: syscall number */
> + /* movl PT_EAX(%esp), %eax already set, syscall number: 1st arg to audit */
> + movl PT_EBX(%esp), %edx /* ebx/a0: 2nd arg to audit */
> + /* movl PT_ECX(%esp), %ecx already set, a1: 3nd arg to audit */
> + pushl_cfi PT_ESI(%esp) /* a3: 5th arg */
> + pushl_cfi PT_EDX+4(%esp) /* a2: 4th arg */

Why are we grabbing that from the stack? AFAICT all arguments are in
the registers still.

Thanks,

tglx


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