Commit deb60015 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Tony Luck
Browse files

Fix broken fsys_getppid() 



In particular fsys_getppid always returns the ppid in the initial pid
namespace so it does not work for a process in a pid namespace.

Fix from Eric Biederman just removes the fast system call path.
While it is a little bit sad to see another one of these bite
the dust ... I can't imagine that getppid() is really on any
real applications critical path.

Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent d7c6797f

arch/ia64/kernel/fsys.S

+1 −48
Original line number Diff line number Diff line
@@ -90,53 +90,6 @@ ENTRY(fsys_getpid) 
	FSYS_RETURN

END(fsys_getpid)



ENTRY(fsys_getppid)

	.prologue

	.altrp b6

	.body

	add r17=IA64_TASK_GROUP_LEADER_OFFSET,r16

	;;

	ld8 r17=[r17]				// r17 = current->group_leader

	add r9=TI_FLAGS+IA64_TASK_SIZE,r16

	;;



	ld4 r9=[r9]

	add r17=IA64_TASK_REAL_PARENT_OFFSET,r17 // r17 = &current->group_leader->real_parent

	;;

	and r9=TIF_ALLWORK_MASK,r9



1:	ld8 r18=[r17]				// r18 = current->group_leader->real_parent

	;;

	cmp.ne p8,p0=0,r9

	add r8=IA64_TASK_TGID_OFFSET,r18	// r8 = &current->group_leader->real_parent->tgid

	;;



	/*

	 * The .acq is needed to ensure that the read of tgid has returned its data before

	 * we re-check "real_parent".

	 */

	ld4.acq r8=[r8]				// r8 = current->group_leader->real_parent->tgid

#ifdef CONFIG_SMP

	/*

	 * Re-read current->group_leader->real_parent.

	 */

	ld8 r19=[r17]				// r19 = current->group_leader->real_parent

(p8)	br.spnt.many fsys_fallback_syscall

	;;

	cmp.ne p6,p0=r18,r19			// did real_parent change?

	mov r19=0			// i must not leak kernel bits...

(p6)	br.cond.spnt.few 1b			// yes -> redo the read of tgid and the check

	;;

	mov r17=0			// i must not leak kernel bits...

	mov r18=0			// i must not leak kernel bits...

#else

	mov r17=0			// i must not leak kernel bits...

	mov r18=0			// i must not leak kernel bits...

	mov r19=0			// i must not leak kernel bits...

#endif

	FSYS_RETURN

END(fsys_getppid)



ENTRY(fsys_set_tid_address)

	.prologue

	.altrp b6
@@ -614,7 +567,7 @@ paravirt_fsyscall_table: 
	data8 0				// chown

	data8 0				// lseek		// 1040

	data8 fsys_getpid		// getpid

	data8 fsys_getppid		// getppid

	data8 0				// getppid

	data8 0				// mount

	data8 0				// umount

	data8 0				// setuid		// 1045