The patch titled
maps2-add-proc-pid-pagemap-interface fix
has been added to the -mm tree. Its filename is
maps2-add-proc-pid-pagemap-interface-fix.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: maps2-add-proc-pid-pagemap-interface fix
From: Matt Mackall <mpm@xxxxxxxxxxx>
When CONFIG_HIGHPTE is enabled, use double-buffering in pagemap to
avoid calling copy_to_user while preemption is disabled.
Tested on x86 with HIGHPTE with DEBUG_SPINLOCK_SLEEP and
PROVE_LOCKING.
Signed-off-by: Matt Mackall <mpm@xxxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 28 ++++++++++++++++++++++++++--
1 files changed, 26 insertions(+), 2 deletions(-)
diff -puN fs/proc/task_mmu.c~maps2-add-proc-pid-pagemap-interface-fix fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~maps2-add-proc-pid-pagemap-interface-fix
+++ a/fs/proc/task_mmu.c
@@ -520,6 +520,7 @@ struct pagemapread {
struct mm_struct *mm;
unsigned long next;
unsigned long *buf;
+ pte_t *ptebuf;
unsigned long pos;
size_t count;
int index;
@@ -558,6 +559,14 @@ static int pagemap_pte_range(pmd_t *pmd,
int err;
pte = pte_offset_map(pmd, addr);
+
+#ifdef CONFIG_HIGHPTE
+ /* copy PTE directory to temporary buffer and unmap it */
+ memcpy(pm->ptebuf, pte, PAGE_ALIGN((unsigned long)pte) - (unsigned long)pte);
+ pte_unmap(pte);
+ pte = pm->ptebuf;
+#endif
+
for (; addr != end; pte++, addr += PAGE_SIZE) {
if (addr < pm->next)
continue;
@@ -568,7 +577,11 @@ static int pagemap_pte_range(pmd_t *pmd,
if (err)
return err;
}
+
+#ifndef CONFIG_HIGHPTE
pte_unmap(pte - 1);
+#endif
+
return 0;
}
@@ -640,10 +653,16 @@ static ssize_t pagemap_read(struct file
if (!page)
goto out;
+#ifdef CONFIG_HIGHPTE
+ pm.ptebuf = kzalloc(PAGE_SIZE, GFP_USER);
+ if (!pm.ptebuf)
+ goto out_free;
+#endif
+
ret = 0;
mm = get_task_mm(task);
if (!mm)
- goto out_free;
+ goto out_freepte;
pm.mm = mm;
pm.next = addr;
@@ -666,7 +685,7 @@ static ssize_t pagemap_read(struct file
while (pm.count > 0 && vma) {
if (!ptrace_may_attach(task)) {
ret = -EIO;
- goto out;
+ goto out_mm;
}
vend = min(vma->vm_start - 1, end - 1) + 1;
ret = pagemap_fill(&pm, vend);
@@ -685,8 +704,13 @@ static ssize_t pagemap_read(struct file
if (!ret)
ret = pm.pos - src;
+out_mm:
mmput(mm);
+out_freepte:
+#ifdef CONFIG_HIGHPTE
+ kfree(pm.ptebuf);
out_free:
+#endif
kfree(page);
out:
put_task_struct(task);
_
Patches currently in -mm which might be from mpm@xxxxxxxxxxx are
slab-introduce-krealloc.patch
slab-introduce-krealloc-fix.patch
smaps-add-clear_refs-file-to-clear-reference-cleanup.patch
maps2-uninline-some-functions-in-the-page-walker.patch
maps2-eliminate-the-pmd_walker-struct-in-the-page-walker.patch
maps2-remove-vma-from-args-in-the-page-walker.patch
maps2-propagate-errors-from-callback-in-page-walker.patch
maps2-add-callbacks-for-each-level-to-page-walker.patch
maps2-move-the-page-walker-code-to-lib.patch
maps2-move-the-page-walker-code-to-lib-fix.patch
maps2-simplify-interdependence-of-proc-pid-maps-and-smaps.patch
maps2-move-clear_refs-code-to-task_mmuc.patch
maps2-regroup-task_mmu-by-interface.patch
maps2-make-proc-pid-smaps-optional-under-config_embedded.patch
maps2-make-proc-pid-clear_refs-option-under-config_embedded.patch
maps2-add-proc-pid-pagemap-interface.patch
maps2-add-proc-pid-pagemap-interface-fix.patch
maps2-add-proc-kpagemap-interface.patch
slob-handle-slab_panic-flag.patch
-
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