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Code Issues Releases Wiki Activity

vdso: Split parasite_fixup_vdso() once more

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It's hard to stop, when you've begun.
No functional change is expected.

Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
This commit is contained in:
Dmitry Safonov 2017-07-17 15:39:56 +03:00 committed by Andrei Vagin
parent e101026bdf
commit e89a2c044a
1 changed files with 101 additions and 77 deletions
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154
criu/vdso.c
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@ -113,9 +113,16 @@ static bool not_vvar_or_vdso(struct vma_area *vma)
return false; return false;
} }
/* Contains addresses from vdso mark */
struct vdso_quarter {
unsigned long orig_vdso;
unsigned long orig_vvar;
unsigned long rt_vdso;
unsigned long rt_vvar;
};
static void drop_rt_vdso(struct vm_area_list *vma_area_list, static void drop_rt_vdso(struct vm_area_list *vma_area_list,
unsigned long orig_vdso_addr, unsigned long orig_vvar_addr, struct vdso_quarter *addr, struct vma_area *rt_vdso_marked)
unsigned long rt_vvar_addr, struct vma_area *rt_vdso_marked)
{ {
struct vma_area *rt_vvar_marked = NULL; struct vma_area *rt_vvar_marked = NULL;
struct vma_area *vma; struct vma_area *vma;
@ -128,7 +135,7 @@ static void drop_rt_vdso(struct vm_area_list *vma_area_list,
* and must be dropped from vma list. * and must be dropped from vma list.
*/ */
pr_debug("vdso: Found marked at %lx (orig vDSO at %lx VVAR at %lx)\n", pr_debug("vdso: Found marked at %lx (orig vDSO at %lx VVAR at %lx)\n",
(long)rt_vdso_marked->e->start, orig_vdso_addr, orig_vvar_addr); (long)rt_vdso_marked->e->start, addr->orig_vdso, addr->orig_vvar);
/* /*
* Don't forget to restore the proxy vdso/vvar status, since * Don't forget to restore the proxy vdso/vvar status, since
@ -136,16 +143,16 @@ static void drop_rt_vdso(struct vm_area_list *vma_area_list,
* Also BTW search for rt-vvar to remove it later. * Also BTW search for rt-vvar to remove it later.
*/ */
list_for_each_entry(vma, &vma_area_list->h, list) { list_for_each_entry(vma, &vma_area_list->h, list) {
if (vma->e->start == orig_vdso_addr) { if (vma->e->start == addr->orig_vdso) {
vma->e->status |= VMA_AREA_REGULAR | VMA_AREA_VDSO; vma->e->status |= VMA_AREA_REGULAR | VMA_AREA_VDSO;
pr_debug("vdso: Restore orig vDSO status at %lx\n", pr_debug("vdso: Restore orig vDSO status at %lx\n",
(long)vma->e->start); (long)vma->e->start);
} else if (vma->e->start == orig_vvar_addr) { } else if (vma->e->start == addr->orig_vvar) {
vma->e->status |= VMA_AREA_REGULAR | VMA_AREA_VVAR; vma->e->status |= VMA_AREA_REGULAR | VMA_AREA_VVAR;
pr_debug("vdso: Restore orig VVAR status at %lx\n", pr_debug("vdso: Restore orig VVAR status at %lx\n",
(long)vma->e->start); (long)vma->e->start);
} else if (rt_vvar_addr != VVAR_BAD_ADDR && } else if (addr->rt_vvar != VVAR_BAD_ADDR &&
rt_vvar_addr == vma->e->start) { addr->rt_vvar == vma->e->start) {
BUG_ON(rt_vvar_marked); BUG_ON(rt_vvar_marked);
if (not_vvar_or_vdso(vma)) { if (not_vvar_or_vdso(vma)) {
pr_warn("Mark in rt-vdso points to vma, that doesn't look like vvar - skipping unmap\n"); pr_warn("Mark in rt-vdso points to vma, that doesn't look like vvar - skipping unmap\n");
@ -170,42 +177,6 @@ static void drop_rt_vdso(struct vm_area_list *vma_area_list,
} }
} }
/*
* The VMAs list might have proxy vdso/vvar areas left
* from previous dump/restore cycle so we need to detect
* them and eliminated from the VMAs list, they will be
* generated again on restore if needed.
*/
int parasite_fixup_vdso(struct parasite_ctl *ctl, pid_t pid,
struct vm_area_list *vma_area_list)
{
unsigned long orig_vdso_addr = VDSO_BAD_ADDR;
unsigned long orig_vvar_addr = VVAR_BAD_ADDR;
unsigned long rt_vvar_addr = VVAR_BAD_ADDR;
struct vma_area *rt_vdso_marked = NULL;
struct parasite_vdso_vma_entry *args;
int fd = -1, exit_code = -1;
enum vdso_check_t vcheck;
struct vma_area *vma;
vcheck = get_vdso_check_type(ctl);
args = compel_parasite_args(ctl, struct parasite_vdso_vma_entry);
if (vcheck == VDSO_CHECK_PFN) {
BUG_ON(vdso_pfn == VDSO_BAD_PFN);
fd = open_proc(pid, "pagemap");
if (fd < 0)
return -1;
}
list_for_each_entry(vma, &vma_area_list->h, list) {
bool has_vdso_pfn = false;
if (not_vvar_or_vdso(vma))
continue;
if ((vma->e->prot & VDSO_PROT) != VDSO_PROT)
continue;
/* /*
* I need to poke every potentially marked vma, * I need to poke every potentially marked vma,
* otherwise if task never called for vdso functions * otherwise if task never called for vdso functions
@ -215,6 +186,21 @@ int parasite_fixup_vdso(struct parasite_ctl *ctl, pid_t pid,
* we have to scan the vma zone for vDSO elf structure * we have to scan the vma zone for vDSO elf structure
* which gonna be a slow way. * which gonna be a slow way.
*/ */
static int check_if_vma_is_vdso(enum vdso_check_t vcheck, int pagemap_fd,
struct parasite_ctl *ctl, struct vma_area *vma,
struct vma_area **rt_vdso_marked, struct vdso_quarter *addr)
{
struct parasite_vdso_vma_entry *args;
bool has_vdso_pfn = false;
args = compel_parasite_args(ctl, struct parasite_vdso_vma_entry);
if (not_vvar_or_vdso(vma))
return 0;
if ((vma->e->prot & VDSO_PROT) != VDSO_PROT)
return 0;
args->start = vma->e->start; args->start = vma->e->start;
args->len = vma_area_len(vma); args->len = vma_area_len(vma);
args->try_fill_symtable = (vcheck == VDSO_CHECK_SYMS); args->try_fill_symtable = (vcheck == VDSO_CHECK_SYMS);
@ -222,32 +208,29 @@ int parasite_fixup_vdso(struct parasite_ctl *ctl, pid_t pid,
if (compel_rpc_call_sync(PARASITE_CMD_CHECK_VDSO_MARK, ctl)) { if (compel_rpc_call_sync(PARASITE_CMD_CHECK_VDSO_MARK, ctl)) {
pr_err("Parasite failed to poke for mark\n"); pr_err("Parasite failed to poke for mark\n");
goto err; return -1;
} }
/*
* Defer handling marked vdso until we walked over
* all vmas and restore potentially remapped vDSO
* area status.
*/
if (unlikely(args->is_marked)) { if (unlikely(args->is_marked)) {
if (rt_vdso_marked) { if (*rt_vdso_marked) {
pr_err("Ow! Second vdso mark detected!\n"); pr_err("Ow! Second vdso mark detected!\n");
goto err; return -1;
} }
rt_vdso_marked = vma; *rt_vdso_marked = vma;
orig_vdso_addr = args->orig_vdso_addr; addr->orig_vdso = args->orig_vdso_addr;
orig_vvar_addr = args->orig_vvar_addr; addr->orig_vvar = args->orig_vvar_addr;
rt_vvar_addr = args->rt_vvar_addr; addr->rt_vvar = args->rt_vvar_addr;
continue; return 0;
} }
if (vcheck == VDSO_NO_CHECK) if (vcheck == VDSO_NO_CHECK)
continue; return 0;
if (vcheck == VDSO_CHECK_PFN && check_vdso_by_pfn(fd, vma, &has_vdso_pfn) < 0) { if (vcheck == VDSO_CHECK_PFN) {
pr_err("Failed checking vdso by pfn for %d\n", pid); if (check_vdso_by_pfn(pagemap_fd, vma, &has_vdso_pfn) < 0) {
goto err; pr_err("Failed checking vdso by pfn\n");
return -1;
}
} }
if (has_vdso_pfn || args->is_vdso) { if (has_vdso_pfn || args->is_vdso) {
@ -263,14 +246,55 @@ int parasite_fixup_vdso(struct parasite_ctl *ctl, pid_t pid,
vma->e->status &= ~VMA_AREA_VDSO; vma->e->status &= ~VMA_AREA_VDSO;
} }
} }
return 0;
} }
drop_rt_vdso(vma_area_list, orig_vdso_addr, orig_vvar_addr, /*
rt_vvar_addr, rt_vdso_marked); * The VMAs list might have proxy vdso/vvar areas left
exit_code = 0; * from previous dump/restore cycle so we need to detect
err: * them and eliminated from the VMAs list, they will be
* generated again on restore if needed.
*/
int parasite_fixup_vdso(struct parasite_ctl *ctl, pid_t pid,
struct vm_area_list *vma_area_list)
{
struct vma_area *rt_vdso_marked = NULL;
struct vdso_quarter addr = {
.orig_vdso = VDSO_BAD_ADDR,
.orig_vvar = VVAR_BAD_ADDR,
.rt_vdso = VDSO_BAD_ADDR,
.rt_vvar = VVAR_BAD_ADDR,
};
enum vdso_check_t vcheck;
struct vma_area *vma;
int fd = -1;
vcheck = get_vdso_check_type(ctl);
if (vcheck == VDSO_CHECK_PFN) {
BUG_ON(vdso_pfn == VDSO_BAD_PFN);
fd = open_proc(pid, "pagemap");
if (fd < 0)
return -1;
}
list_for_each_entry(vma, &vma_area_list->h, list) {
/*
* Defer handling marked vdso until we walked over
* all vmas and restore potentially remapped vDSO
* area status.
*/
if (check_if_vma_is_vdso(vcheck, fd, ctl, vma,
&rt_vdso_marked, &addr)) {
close_safe(&fd); close_safe(&fd);
return exit_code; return -1;
}
}
drop_rt_vdso(vma_area_list, &addr, rt_vdso_marked);
close_safe(&fd);
return 0;
} }
static int vdso_parse_maps(pid_t pid, struct vdso_maps *s) static int vdso_parse_maps(pid_t pid, struct vdso_maps *s)