[CRIU] [PATCH 05/10] parasite: Add @pad argument for syscall run
Cyrill Gorcunov
gorcunov at openvz.org
Mon Sep 28 12:01:37 PDT 2015
We will need an extra space for memfd based
syscall (without poking the stack since it's
not that safe without additional tests).
So add @pad argument which will be used
to find proper memory for seized syscall
execution.
Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
---
parasite-syscall.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/parasite-syscall.c b/parasite-syscall.c
index 9406f84ac544..eb2bfe0d4153 100644
--- a/parasite-syscall.c
+++ b/parasite-syscall.c
@@ -39,19 +39,23 @@
#include "asm/restorer.h"
#include "pie/pie-relocs.h"
-static int can_run_syscall(unsigned long ip, unsigned long start, unsigned long end)
+static int can_run_syscall(unsigned long ip, unsigned long start,
+ unsigned long end, unsigned long pad)
{
- return ip >= start && ip < (end - code_syscall_size);
+ return ip >= start && ip < (end - code_syscall_size - pad);
}
-static int syscall_fits_vma_area(struct vma_area *vma_area)
+static int syscall_fits_vma_area(struct vma_area *vma_area, unsigned long pad)
{
return can_run_syscall((unsigned long)vma_area->e->start,
(unsigned long)vma_area->e->start,
- (unsigned long)vma_area->e->end);
+ (unsigned long)vma_area->e->end,
+ pad);
}
-static struct vma_area *get_vma_by_ip(struct list_head *vma_area_list, unsigned long ip)
+static struct vma_area *get_vma_by_ip(struct list_head *vma_area_list,
+ unsigned long ip,
+ unsigned long pad)
{
struct vma_area *vma_area;
@@ -60,7 +64,7 @@ static struct vma_area *get_vma_by_ip(struct list_head *vma_area_list, unsigned
continue;
if (!(vma_area->e->prot & PROT_EXEC))
continue;
- if (syscall_fits_vma_area(vma_area))
+ if (syscall_fits_vma_area(vma_area, pad))
return vma_area;
}
@@ -1099,7 +1103,7 @@ struct parasite_ctl *parasite_prep_ctl(pid_t pid, struct vm_area_list *vma_area_
return ctl;
/* Search a place for injecting syscall */
- vma_area = get_vma_by_ip(&vma_area_list->h, REG_IP(ctl->orig.regs));
+ vma_area = get_vma_by_ip(&vma_area_list->h, REG_IP(ctl->orig.regs), 0);
if (!vma_area) {
pr_err("No suitable VMA found to run parasite "
"bootstrap code (pid: %d)\n", pid);
--
2.4.3
More information about the CRIU
mailing list