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Merge branch 'mm-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull vmap stack fixes from Ingo Molnar:
 "This is fallout from CONFIG_HAVE_ARCH_VMAP_STACK=y on x86: stack
  accesses that used to be just somewhat questionable are now totally
  buggy.

  These changes try to do it without breaking the ABI: the fields are
  left there, they are just reporting zero, or reporting narrower
  information (the maps file change)"

* 'mm-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  mm: Change vm_is_stack_for_task() to vm_is_stack_for_current()
  fs/proc: Stop trying to report thread stacks
  fs/proc: Stop reporting eip and esp in /proc/PID/stat
  mm/numa: Remove duplicated include from mprotect.c
This commit is contained in:
Linus Torvalds 2016-10-22 09:39:10 -07:00
commit 86c5bf7101
8 changed files with 29 additions and 70 deletions
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26
Documentation/filesystems/proc.txt
View File

@ -395,32 +395,6 @@ is not associated with a file:
or if empty, the mapping is anonymous.
The /proc/PID/task/TID/maps is a view of the virtual memory from the viewpoint
of the individual tasks of a process. In this file you will see a mapping marked
as [stack] if that task sees it as a stack. Hence, for the example above, the
task-level map, i.e. /proc/PID/task/TID/maps for thread 1001 will look like this:
08048000-08049000 r-xp 00000000 03:00 8312 /opt/test
08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test
0804a000-0806b000 rw-p 00000000 00:00 0 [heap]
a7cb1000-a7cb2000 ---p 00000000 00:00 0
a7cb2000-a7eb2000 rw-p 00000000 00:00 0
a7eb2000-a7eb3000 ---p 00000000 00:00 0
a7eb3000-a7ed5000 rw-p 00000000 00:00 0 [stack]
a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6
a8008000-a800a000 r--p 00133000 03:00 4222 /lib/libc.so.6
a800a000-a800b000 rw-p 00135000 03:00 4222 /lib/libc.so.6
a800b000-a800e000 rw-p 00000000 00:00 0
a800e000-a8022000 r-xp 00000000 03:00 14462 /lib/libpthread.so.0
a8022000-a8023000 r--p 00013000 03:00 14462 /lib/libpthread.so.0
a8023000-a8024000 rw-p 00014000 03:00 14462 /lib/libpthread.so.0
a8024000-a8027000 rw-p 00000000 00:00 0
a8027000-a8043000 r-xp 00000000 03:00 8317 /lib/ld-linux.so.2
a8043000-a8044000 r--p 0001b000 03:00 8317 /lib/ld-linux.so.2
a8044000-a8045000 rw-p 0001c000 03:00 8317 /lib/ld-linux.so.2
aff35000-aff4a000 rw-p 00000000 00:00 0
ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso]
The /proc/PID/smaps is an extension based on maps, showing the memory
consumption for each of the process's mappings. For each of mappings there
is a series of lines such as the following:

9
fs/proc/array.c
View File

@ -412,10 +412,11 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
mm = get_task_mm(task);
if (mm) {
vsize = task_vsize(mm);
if (permitted) {
eip = KSTK_EIP(task);
esp = KSTK_ESP(task);
}
/*
* esp and eip are intentionally zeroed out. There is no
* non-racy way to read them without freezing the task.
* Programs that need reliable values can use ptrace(2).
*/
}
get_task_comm(tcomm, task);

29
fs/proc/task_mmu.c
View File

@ -266,24 +266,15 @@ static int do_maps_open(struct inode *inode, struct file *file,
* /proc/PID/maps that is the stack of the main task.
*/
static int is_stack(struct proc_maps_private *priv,
struct vm_area_struct *vma, int is_pid)
struct vm_area_struct *vma)
{
int stack = 0;
if (is_pid) {
stack = vma->vm_start <= vma->vm_mm->start_stack &&
vma->vm_end >= vma->vm_mm->start_stack;
} else {
struct inode *inode = priv->inode;
struct task_struct *task;
rcu_read_lock();
task = pid_task(proc_pid(inode), PIDTYPE_PID);
if (task)
stack = vma_is_stack_for_task(vma, task);
rcu_read_unlock();
}
return stack;
/*
* We make no effort to guess what a given thread considers to be
* its "stack". It's not even well-defined for programs written
* languages like Go.
*/
return vma->vm_start <= vma->vm_mm->start_stack &&
vma->vm_end >= vma->vm_mm->start_stack;
}
static void
@ -354,7 +345,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
goto done;
}
if (is_stack(priv, vma, is_pid))
if (is_stack(priv, vma))
name = "[stack]";
}
@ -1669,7 +1660,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
seq_file_path(m, file, "\n\t= ");
} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
seq_puts(m, " heap");
} else if (is_stack(proc_priv, vma, is_pid)) {
} else if (is_stack(proc_priv, vma)) {
seq_puts(m, " stack");
}

26
fs/proc/task_nommu.c
View File

@ -124,25 +124,17 @@ unsigned long task_statm(struct mm_struct *mm,
}
static int is_stack(struct proc_maps_private *priv,
struct vm_area_struct *vma, int is_pid)
struct vm_area_struct *vma)
{
struct mm_struct *mm = vma->vm_mm;
int stack = 0;
if (is_pid) {
stack = vma->vm_start <= mm->start_stack &&
vma->vm_end >= mm->start_stack;
} else {
struct inode *inode = priv->inode;
struct task_struct *task;
rcu_read_lock();
task = pid_task(proc_pid(inode), PIDTYPE_PID);
if (task)
stack = vma_is_stack_for_task(vma, task);
rcu_read_unlock();
}
return stack;
/*
* We make no effort to guess what a given thread considers to be
* its "stack". It's not even well-defined for programs written
* languages like Go.
*/
return vma->vm_start <= mm->start_stack &&
vma->vm_end >= mm->start_stack;
}
/*
@ -184,7 +176,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
if (file) {
seq_pad(m, ' ');
seq_file_path(m, file, "");
} else if (mm && is_stack(priv, vma, is_pid)) {
} else if (mm && is_stack(priv, vma)) {
seq_pad(m, ' ');
seq_printf(m, "[stack]");
}

2
include/linux/mm.h
View File

@ -1391,7 +1391,7 @@ static inline int stack_guard_page_end(struct vm_area_struct *vma,
!vma_growsup(vma->vm_next, addr);
}
int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t);
int vma_is_stack_for_current(struct vm_area_struct *vma);
extern unsigned long move_page_tables(struct vm_area_struct *vma,
unsigned long old_addr, struct vm_area_struct *new_vma,

1
mm/mprotect.c
View File

@ -25,7 +25,6 @@
#include <linux/perf_event.h>
#include <linux/pkeys.h>
#include <linux/ksm.h>
#include <linux/pkeys.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>

4
mm/util.c
View File

@ -230,8 +230,10 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
}
/* Check if the vma is being used as a stack by this task */
int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t)
int vma_is_stack_for_current(struct vm_area_struct *vma)
{
struct task_struct * __maybe_unused t = current;
return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
}

2
security/selinux/hooks.c
View File

@ -3557,7 +3557,7 @@ static int selinux_file_mprotect(struct vm_area_struct *vma,
} else if (!vma->vm_file &&
((vma->vm_start <= vma->vm_mm->start_stack &&
vma->vm_end >= vma->vm_mm->start_stack) ||
vma_is_stack_for_task(vma, current))) {
vma_is_stack_for_current(vma))) {
rc = current_has_perm(current, PROCESS__EXECSTACK);
} else if (vma->vm_file && vma->anon_vma) {
/*