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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: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Eric W. Biederman 2013-03-18 17:03:03 -07:00 committed by Tony Luck
parent d7c6797fbc
commit deb6001509
1 changed files with 1 additions and 48 deletions
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49
arch/ia64/kernel/fsys.S
View File

@ -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