The patch titled
Subject: kcov: properly handle subsequent mmap calls
has been removed from the -mm tree. Its filename was
kcov-properly-handle-subsequent-mmap-calls.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Aleksandr Nogikh <nogikh@xxxxxxxxxx>
Subject: kcov: properly handle subsequent mmap calls
Allocate the kcov buffer during KCOV_MODE_INIT in order to untie mmapping
of a kcov instance and the actual coverage collection process. Modify
kcov_mmap, so that it can be reliably used any number of times once
KCOV_MODE_INIT has succeeded.
These changes to the user-facing interface of the tool only weaken the
preconditions, so all existing user space code should remain compatible
with the new version.
Link: https://lkml.kernel.org/r/20220117153634.150357-3-nogikh@xxxxxxxxxx
Signed-off-by: Aleksandr Nogikh <nogikh@xxxxxxxxxx>
Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Taras Madan <tarasmadan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kcov.c | 34 +++++++++++++++-------------------
1 file changed, 15 insertions(+), 19 deletions(-)
--- a/kernel/kcov.c~kcov-properly-handle-subsequent-mmap-calls
+++ a/kernel/kcov.c
@@ -459,37 +459,28 @@ void kcov_task_exit(struct task_struct *
static int kcov_mmap(struct file *filep, struct vm_area_struct *vma)
{
int res = 0;
- void *area;
struct kcov *kcov = vma->vm_file->private_data;
unsigned long size, off;
struct page *page;
unsigned long flags;
- area = vmalloc_user(vma->vm_end - vma->vm_start);
- if (!area)
- return -ENOMEM;
-
spin_lock_irqsave(&kcov->lock, flags);
size = kcov->size * sizeof(unsigned long);
- if (kcov->mode != KCOV_MODE_INIT || vma->vm_pgoff != 0 ||
+ if (kcov->area == NULL || vma->vm_pgoff != 0 ||
vma->vm_end - vma->vm_start != size) {
res = -EINVAL;
goto exit;
}
- if (!kcov->area) {
- kcov->area = area;
- vma->vm_flags |= VM_DONTEXPAND;
- spin_unlock_irqrestore(&kcov->lock, flags);
- for (off = 0; off < size; off += PAGE_SIZE) {
- page = vmalloc_to_page(kcov->area + off);
- if (vm_insert_page(vma, vma->vm_start + off, page))
- WARN_ONCE(1, "vm_insert_page() failed");
- }
- return 0;
+ spin_unlock_irqrestore(&kcov->lock, flags);
+ vma->vm_flags |= VM_DONTEXPAND;
+ for (off = 0; off < size; off += PAGE_SIZE) {
+ page = vmalloc_to_page(kcov->area + off);
+ if (vm_insert_page(vma, vma->vm_start + off, page))
+ WARN_ONCE(1, "vm_insert_page() failed");
}
+ return 0;
exit:
spin_unlock_irqrestore(&kcov->lock, flags);
- vfree(area);
return res;
}
@@ -674,6 +665,7 @@ static long kcov_ioctl(struct file *file
unsigned int remote_num_handles;
unsigned long remote_arg_size;
unsigned long size, flags;
+ void *area;
kcov = filep->private_data;
switch (cmd) {
@@ -683,17 +675,21 @@ static long kcov_ioctl(struct file *file
* Must happen before anything else.
*
* First check the size argument - it must be at least 2
- * to hold the current position and one PC. Later we allocate
- * size * sizeof(unsigned long) memory, that must not overflow.
+ * to hold the current position and one PC.
*/
size = arg;
if (size < 2 || size > INT_MAX / sizeof(unsigned long))
return -EINVAL;
+ area = vmalloc_user(size * sizeof(unsigned long));
+ if (area == NULL)
+ return -ENOMEM;
spin_lock_irqsave(&kcov->lock, flags);
if (kcov->mode != KCOV_MODE_DISABLED) {
spin_unlock_irqrestore(&kcov->lock, flags);
+ vfree(area);
return -EBUSY;
}
+ kcov->area = area;
kcov->size = size;
kcov->mode = KCOV_MODE_INIT;
spin_unlock_irqrestore(&kcov->lock, flags);
_
Patches currently in -mm which might be from nogikh@xxxxxxxxxx are
