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-rw-r--r--Documentation/filesystems/proc.txt6
-rw-r--r--fs/proc/task_mmu.c63
-rw-r--r--include/linux/mm.h2
-rw-r--r--include/linux/mm_types.h15
-rw-r--r--include/linux/prctl.h3
-rw-r--r--kernel/sys.c146
-rw-r--r--mm/madvise.c3
-rw-r--r--mm/mempolicy.c5
-rw-r--r--mm/mlock.c3
-rw-r--r--mm/mmap.c44
-rw-r--r--mm/mprotect.c3
11 files changed, 269 insertions, 24 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index db3b1aba32a..6b0d09873be 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -354,6 +354,8 @@ is not associated with a file:
[stack] = the stack of the main process
[vdso] = the "virtual dynamic shared object",
the kernel system call handler
+ [anon:<name>] = an anonymous mapping that has been
+ named by userspace
or if empty, the mapping is anonymous.
@@ -376,6 +378,7 @@ Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 374 kB
+Name: name from userspace
The first of these lines shows the same information as is displayed for the
mapping in /proc/PID/maps. The remaining lines show the size of the mapping
@@ -391,6 +394,9 @@ and a page is modified, the file page is replaced by a private anonymous copy.
"Swap" shows how much would-be-anonymous memory is also used, but out on
swap.
+The "Name" field will only be present on a mapping that has been named by
+userspace, and will show the name passed in by userspace.
+
This file is only present if the CONFIG_MMU kernel configuration option is
enabled.
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 00e7ac486d9..f43c5406b56 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -88,6 +88,56 @@ static void pad_len_spaces(struct seq_file *m, int len)
seq_printf(m, "%*c", len, ' ');
}
+static void seq_print_vma_name(struct seq_file *m, struct vm_area_struct *vma)
+{
+ const char __user *name = vma_get_anon_name(vma);
+ struct mm_struct *mm = vma->vm_mm;
+
+ unsigned long page_start_vaddr;
+ unsigned long page_offset;
+ unsigned long num_pages;
+ unsigned long max_len = NAME_MAX;
+ int i;
+
+ page_start_vaddr = (unsigned long)name & PAGE_MASK;
+ page_offset = (unsigned long)name - page_start_vaddr;
+ num_pages = DIV_ROUND_UP(page_offset + max_len, PAGE_SIZE);
+
+ seq_puts(m, "[anon:");
+
+ for (i = 0; i < num_pages; i++) {
+ int len;
+ int write_len;
+ const char *kaddr;
+ long pages_pinned;
+ struct page *page;
+
+ pages_pinned = get_user_pages(current, mm, page_start_vaddr,
+ 1, 0, 0, &page, NULL);
+ if (pages_pinned < 1) {
+ seq_puts(m, "<fault>]");
+ return;
+ }
+
+ kaddr = (const char *)kmap(page);
+ len = min(max_len, PAGE_SIZE - page_offset);
+ write_len = strnlen(kaddr + page_offset, len);
+ seq_write(m, kaddr + page_offset, write_len);
+ kunmap(page);
+ put_page(page);
+
+ /* if strnlen hit a null terminator then we're done */
+ if (write_len != len)
+ break;
+
+ max_len -= len;
+ page_offset = 0;
+ page_start_vaddr += PAGE_SIZE;
+ }
+
+ seq_putc(m, ']');
+}
+
static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma)
{
if (vma && vma != priv->tail_vma) {
@@ -264,7 +314,14 @@ static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
} else {
name = "[vdso]";
}
+ goto done;
}
+
+ if (vma_get_anon_name(vma)) {
+ pad_len_spaces(m, len);
+ seq_print_vma_name(m, vma);
+ }
+done:
if (name) {
pad_len_spaces(m, len);
seq_puts(m, name);
@@ -474,6 +531,12 @@ static int show_smap(struct seq_file *m, void *v)
(vma->vm_flags & VM_LOCKED) ?
(unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
+ if (vma_get_anon_name(vma)) {
+ seq_puts(m, "Name: ");
+ seq_print_vma_name(m, vma);
+ seq_putc(m, '\n');
+ }
+
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task->mm))
? vma->vm_start : 0;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d5dc6af4ff6..92a055bd3dd 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1418,7 +1418,7 @@ extern int vma_adjust(struct vm_area_struct *vma, unsigned long start,
extern struct vm_area_struct *vma_merge(struct mm_struct *,
struct vm_area_struct *prev, unsigned long addr, unsigned long end,
unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
- struct mempolicy *);
+ struct mempolicy *, const char __user *);
extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
extern int split_vma(struct mm_struct *,
struct vm_area_struct *, unsigned long addr, int new_below);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 059839c7000..557f9b69bfb 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -162,6 +162,10 @@ struct vm_area_struct {
* linkage into the address_space->i_mmap prio tree, or
* linkage to the list of like vmas hanging off its node, or
* linkage of vma in the address_space->i_mmap_nonlinear list.
+ *
+ * For private anonymous mappings, a pointer to a null terminated string
+ * in the user process containing the name given to the vma, or NULL
+ * if unnamed.
*/
union {
struct {
@@ -171,6 +175,7 @@ struct vm_area_struct {
} vm_set;
struct raw_prio_tree_node prio_tree_node;
+ const char __user *anon_name;
} shared;
/*
@@ -345,4 +350,14 @@ static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
return mm->cpu_vm_mask_var;
}
+
+/* Return the name for an anonymous mapping or NULL for a file-backed mapping */
+static inline const char __user *vma_get_anon_name(struct vm_area_struct *vma)
+{
+ if (vma->vm_file)
+ return NULL;
+
+ return vma->shared.anon_name;
+}
+
#endif /* _LINUX_MM_TYPES_H */
diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index a3baeb2c216..dd90287deeb 100644
--- a/include/linux/prctl.h
+++ b/include/linux/prctl.h
@@ -102,4 +102,7 @@
#define PR_MCE_KILL_GET 34
+#define PR_SET_VMA 0x53564d41
+# define PR_SET_VMA_ANON_NAME 0
+
#endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index be53817497c..79b66c09844 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -40,6 +40,9 @@
#include <linux/syscore_ops.h>
#include <linux/version.h>
#include <linux/ctype.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/mempolicy.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
@@ -1660,6 +1663,146 @@ SYSCALL_DEFINE1(umask, int, mask)
return mask;
}
+
+static int prctl_update_vma_anon_name(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start, unsigned long end,
+ const char __user *name_addr)
+{
+ struct mm_struct * mm = vma->vm_mm;
+ int error = 0;
+ pgoff_t pgoff;
+
+ if (name_addr == vma_get_anon_name(vma)) {
+ *prev = vma;
+ goto out;
+ }
+
+ pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
+ *prev = vma_merge(mm, *prev, start, end, vma->vm_flags, vma->anon_vma,
+ vma->vm_file, pgoff, vma_policy(vma),
+ name_addr);
+ if (*prev) {
+ vma = *prev;
+ goto success;
+ }
+
+ *prev = vma;
+
+ if (start != vma->vm_start) {
+ error = split_vma(mm, vma, start, 1);
+ if (error)
+ goto out;
+ }
+
+ if (end != vma->vm_end) {
+ error = split_vma(mm, vma, end, 0);
+ if (error)
+ goto out;
+ }
+
+success:
+ if (!vma->vm_file)
+ vma->shared.anon_name = name_addr;
+
+out:
+ if (error == -ENOMEM)
+ error = -EAGAIN;
+ return error;
+}
+
+static int prctl_set_vma_anon_name(unsigned long start, unsigned long end,
+ unsigned long arg)
+{
+ unsigned long tmp;
+ struct vm_area_struct * vma, *prev;
+ int unmapped_error = 0;
+ int error = -EINVAL;
+
+ /*
+ * If the interval [start,end) covers some unmapped address
+ * ranges, just ignore them, but return -ENOMEM at the end.
+ * - this matches the handling in madvise.
+ */
+ vma = find_vma_prev(current->mm, start, &prev);
+ if (vma && start > vma->vm_start)
+ prev = vma;
+
+ for (;;) {
+ /* Still start < end. */
+ error = -ENOMEM;
+ if (!vma)
+ return error;
+
+ /* Here start < (end|vma->vm_end). */
+ if (start < vma->vm_start) {
+ unmapped_error = -ENOMEM;
+ start = vma->vm_start;
+ if (start >= end)
+ return error;
+ }
+
+ /* Here vma->vm_start <= start < (end|vma->vm_end) */
+ tmp = vma->vm_end;
+ if (end < tmp)
+ tmp = end;
+
+ /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
+ error = prctl_update_vma_anon_name(vma, &prev, start, end,
+ (const char __user *)arg);
+ if (error)
+ return error;
+ start = tmp;
+ if (prev && start < prev->vm_end)
+ start = prev->vm_end;
+ error = unmapped_error;
+ if (start >= end)
+ return error;
+ if (prev)
+ vma = prev->vm_next;
+ else /* madvise_remove dropped mmap_sem */
+ vma = find_vma(current->mm, start);
+ }
+}
+
+static int prctl_set_vma(unsigned long opt, unsigned long start,
+ unsigned long len_in, unsigned long arg)
+{
+ struct mm_struct *mm = current->mm;
+ int error;
+ unsigned long len;
+ unsigned long end;
+
+ if (start & ~PAGE_MASK)
+ return -EINVAL;
+ len = (len_in + ~PAGE_MASK) & PAGE_MASK;
+
+ /* Check to see whether len was rounded up from small -ve to zero */
+ if (len_in && !len)
+ return -EINVAL;
+
+ end = start + len;
+ if (end < start)
+ return -EINVAL;
+
+ if (end == start)
+ return 0;
+
+ down_write(&mm->mmap_sem);
+
+ switch (opt) {
+ case PR_SET_VMA_ANON_NAME:
+ error = prctl_set_vma_anon_name(start, end, arg);
+ break;
+ default:
+ error = -EINVAL;
+ }
+
+ up_write(&mm->mmap_sem);
+
+ return error;
+}
+
SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
unsigned long, arg4, unsigned long, arg5)
{
@@ -1808,6 +1951,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
else
error = PR_MCE_KILL_DEFAULT;
break;
+ case PR_SET_VMA:
+ error = prctl_set_vma(arg2, arg3, arg4, arg5);
+ break;
default:
error = -EINVAL;
break;
diff --git a/mm/madvise.c b/mm/madvise.c
index deabe5f603a..5a273afd199 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -87,7 +87,8 @@ static long madvise_behavior(struct vm_area_struct * vma,
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
*prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma,
- vma->vm_file, pgoff, vma_policy(vma));
+ vma->vm_file, pgoff, vma_policy(vma),
+ vma_get_anon_name(vma));
if (*prev) {
vma = *prev;
goto success;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 7065fb3a2b4..7c8caa9bc0a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -664,8 +664,9 @@ static int mbind_range(struct mm_struct *mm, unsigned long start,
vmend = min(end, vma->vm_end);
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
- prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
- vma->anon_vma, vma->vm_file, pgoff, new_pol);
+ prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
+ vma->anon_vma, vma->vm_file, pgoff,
+ new_pol, vma_get_anon_name(name));
if (prev) {
vma = prev;
next = vma->vm_next;
diff --git a/mm/mlock.c b/mm/mlock.c
index b41b3b7788f..734fd7f08f9 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -321,7 +321,8 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
*prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
- vma->vm_file, pgoff, vma_policy(vma));
+ vma->vm_file, pgoff, vma_policy(vma),
+ vma_get_anon_name(vma));
if (*prev) {
vma = *prev;
goto success;
diff --git a/mm/mmap.c b/mm/mmap.c
index d1cf520e511..96f124e15a8 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -656,7 +656,8 @@ again: remove_next = 1 + (end > next->vm_end);
* per-vma resources, so we don't attempt to merge those.
*/
static inline int is_mergeable_vma(struct vm_area_struct *vma,
- struct file *file, unsigned long vm_flags)
+ struct file *file, unsigned long vm_flags,
+ const char __user *anon_name)
{
/* VM_CAN_NONLINEAR may get set later by f_op->mmap() */
if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR)
@@ -665,6 +666,8 @@ static inline int is_mergeable_vma(struct vm_area_struct *vma,
return 0;
if (vma->vm_ops && vma->vm_ops->close)
return 0;
+ if (vma_get_anon_name(vma) != anon_name)
+ return 0;
return 1;
}
@@ -695,9 +698,10 @@ static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
*/
static int
can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
- struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
+ struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff,
+ const char __user *anon_name)
{
- if (is_mergeable_vma(vma, file, vm_flags) &&
+ if (is_mergeable_vma(vma, file, vm_flags, anon_name) &&
is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
if (vma->vm_pgoff == vm_pgoff)
return 1;
@@ -714,9 +718,10 @@ can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
*/
static int
can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
- struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
+ struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff,
+ const char __user *anon_name)
{
- if (is_mergeable_vma(vma, file, vm_flags) &&
+ if (is_mergeable_vma(vma, file, vm_flags, anon_name) &&
is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
pgoff_t vm_pglen;
vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
@@ -727,9 +732,9 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
}
/*
- * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
- * whether that can be merged with its predecessor or its successor.
- * Or both (it neatly fills a hole).
+ * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name),
+ * figure out whether that can be merged with its predecessor or its
+ * successor. Or both (it neatly fills a hole).
*
* In most cases - when called for mmap, brk or mremap - [addr,end) is
* certain not to be mapped by the time vma_merge is called; but when
@@ -759,7 +764,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
struct vm_area_struct *prev, unsigned long addr,
unsigned long end, unsigned long vm_flags,
struct anon_vma *anon_vma, struct file *file,
- pgoff_t pgoff, struct mempolicy *policy)
+ pgoff_t pgoff, struct mempolicy *policy,
+ const char __user *anon_name)
{
pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
struct vm_area_struct *area, *next;
@@ -785,15 +791,15 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
*/
if (prev && prev->vm_end == addr &&
mpol_equal(vma_policy(prev), policy) &&
- can_vma_merge_after(prev, vm_flags,
- anon_vma, file, pgoff)) {
+ can_vma_merge_after(prev, vm_flags, anon_vma,
+ file, pgoff, anon_name)) {
/*
* OK, it can. Can we now merge in the successor as well?
*/
if (next && end == next->vm_start &&
mpol_equal(policy, vma_policy(next)) &&
- can_vma_merge_before(next, vm_flags,
- anon_vma, file, pgoff+pglen) &&
+ can_vma_merge_before(next, vm_flags, anon_vma,
+ file, pgoff+pglen, anon_name) &&
is_mergeable_anon_vma(prev->anon_vma,
next->anon_vma, NULL)) {
/* cases 1, 6 */
@@ -813,8 +819,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
*/
if (next && end == next->vm_start &&
mpol_equal(policy, vma_policy(next)) &&
- can_vma_merge_before(next, vm_flags,
- anon_vma, file, pgoff+pglen)) {
+ can_vma_merge_before(next, vm_flags, anon_vma,
+ file, pgoff+pglen, anon_name)) {
if (prev && addr < prev->vm_end) /* case 4 */
err = vma_adjust(prev, prev->vm_start,
addr, prev->vm_pgoff, NULL);
@@ -1251,7 +1257,8 @@ munmap_back:
/*
* Can we just expand an old mapping?
*/
- vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
+ vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff,
+ NULL, NULL);
if (vma)
goto out;
@@ -2202,7 +2209,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
/* Can we just expand an old private anonymous mapping? */
vma = vma_merge(mm, prev, addr, addr + len, flags,
- NULL, NULL, pgoff, NULL);
+ NULL, NULL, pgoff, NULL, NULL);
if (vma)
goto out;
@@ -2340,7 +2347,8 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
- vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
+ vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
+ vma_get_anon_name(vma));
if (new_vma) {
/*
* Source vma may have been merged into new_vma
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 5a688a2756b..5f168ebd9fb 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -179,7 +179,8 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
*/
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
*pprev = vma_merge(mm, *pprev, start, end, newflags,
- vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
+ vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
+ vma_get_anon_name(vma));
if (*pprev) {
vma = *pprev;
goto success;
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-01 19:04:40 +0000