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Code Issues Releases Wiki Activity

vdso/restorer: Always track vdso/vvar positions in vdso_maps_rt

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For simplicity, make them always valid in restorer.
rt->vdso_start will be used to calculate gettimeofday() address.

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
This commit is contained in:
Dmitry Safonov
2019-07-25 23:01:10 +01:00
committed by Andrei Vagin
parent f451fa996a
commit 0918c76676
3 changed files with 60 additions and 68 deletions
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3
criu/include/parasite-vdso.h
View File

@@ -84,8 +84,7 @@ static inline bool is_vdso_mark(void *addr)
extern int vdso_do_park(struct vdso_maps *rt, unsigned long park_at,
unsigned long park_size);
extern int vdso_map_compat(unsigned long map_at);
extern int vdso_proxify(struct vdso_symtable *sym_rt, bool *added_proxy,
unsigned long vdso_rt_parked_at,
extern int vdso_proxify(struct vdso_maps *rt, bool *added_proxy,
VmaEntry *vmas, size_t nr_vmas,
bool compat_vdso, bool force_trampolines);
extern int vdso_redirect_calls(unsigned long base_to, unsigned long base_from,

81
criu/pie/parasite-vdso.c
View File

@@ -24,19 +24,19 @@
#endif
#define LOG_PREFIX "vdso: "
static int vdso_remap(char *who, unsigned long from, unsigned long to, size_t size)
/* Updates @from on success */
static int vdso_remap(char *who, unsigned long *from, unsigned long to, size_t size)
{
unsigned long addr;
pr_debug("Remap %s %lx -> %lx\n", who, from, to);
pr_debug("Remap %s %lx -> %lx\n", who, *from, to);
addr = sys_mremap(from, size, size, MREMAP_MAYMOVE | MREMAP_FIXED, to);
addr = sys_mremap(*from, size, size, MREMAP_MAYMOVE | MREMAP_FIXED, to);
if (addr != to) {
pr_err("Unable to remap %lx -> %lx %lx\n",
from, to, addr);
pr_err("Unable to remap %lx -> %lx %lx\n", *from, to, addr);
return -1;
}
*from = addr;
return 0;
}
@@ -57,7 +57,7 @@ int vdso_do_park(struct vdso_maps *rt, unsigned long park_at,
if (rt->vvar_start == VVAR_BAD_ADDR) {
BUG_ON(vdso_size < park_size);
return vdso_remap("rt-vdso", rt->vdso_start,
return vdso_remap("rt-vdso", &rt->vdso_start,
rt_vdso_park, vdso_size);
}
@@ -68,8 +68,8 @@ int vdso_do_park(struct vdso_maps *rt, unsigned long park_at,
else
rt_vdso_park = park_at + vvar_size;
ret = vdso_remap("rt-vdso", rt->vdso_start, rt_vdso_park, vdso_size);
ret |= vdso_remap("rt-vvar", rt->vvar_start, rt_vvar_park, vvar_size);
ret = vdso_remap("rt-vdso", &rt->vdso_start, rt_vdso_park, vdso_size);
ret |= vdso_remap("rt-vvar", &rt->vvar_start, rt_vvar_park, vvar_size);
return ret;
}
@@ -144,10 +144,8 @@ static bool blobs_matches(VmaEntry *vdso_img, VmaEntry *vvar_img,
* to dumpee position without generating any proxy.
*/
static int remap_rt_vdso(VmaEntry *vma_vdso, VmaEntry *vma_vvar,
struct vdso_symtable *sym_rt, unsigned long vdso_rt_parked_at)
struct vdso_maps *rt)
{
unsigned long rt_vvar_addr = vdso_rt_parked_at;
unsigned long rt_vdso_addr = vdso_rt_parked_at;
void *remap_addr;
int ret;
@@ -164,8 +162,8 @@ static int remap_rt_vdso(VmaEntry *vma_vdso, VmaEntry *vma_vvar,
}
if (!vma_vvar) {
return vdso_remap("rt-vdso", rt_vdso_addr,
vma_vdso->start, sym_rt->vdso_size);
return vdso_remap("rt-vdso", &rt->vdso_start,
vma_vdso->start, rt->sym.vdso_size);
}
remap_addr = (void *)(uintptr_t)vma_vvar->start;
@@ -174,15 +172,10 @@ static int remap_rt_vdso(VmaEntry *vma_vdso, VmaEntry *vma_vvar,
return -1;
}
if (vma_vdso->start < vma_vvar->start)
rt_vvar_addr = vdso_rt_parked_at + sym_rt->vdso_size;
else
rt_vdso_addr = vdso_rt_parked_at + sym_rt->vvar_size;
ret = vdso_remap("rt-vdso", rt_vdso_addr,
vma_vdso->start, sym_rt->vdso_size);
ret |= vdso_remap("rt-vvar", rt_vvar_addr,
vma_vvar->start, sym_rt->vvar_size);
ret = vdso_remap("rt-vdso", &rt->vdso_start,
vma_vdso->start, rt->sym.vdso_size);
ret |= vdso_remap("rt-vvar", &rt->vvar_start,
vma_vvar->start, rt->sym.vvar_size);
return ret;
}
@@ -193,28 +186,14 @@ static int remap_rt_vdso(VmaEntry *vma_vdso, VmaEntry *vma_vvar,
* to operate as proxy vdso.
*/
static int add_vdso_proxy(VmaEntry *vma_vdso, VmaEntry *vma_vvar,
struct vdso_symtable *sym_img, struct vdso_symtable *sym_rt,
unsigned long vdso_rt_parked_at, bool compat_vdso)
struct vdso_symtable *sym_img, struct vdso_maps *rt,
bool compat_vdso)
{
unsigned long rt_vvar_addr = vdso_rt_parked_at;
unsigned long rt_vdso_addr = vdso_rt_parked_at;
unsigned long orig_vvar_addr =
vma_vvar ? vma_vvar->start : VVAR_BAD_ADDR;
pr_info("Runtime vdso mismatches dumpee, generate proxy\n");
/*
* Don't forget to shift if vvar is before vdso.
*/
if (sym_rt->vvar_size == VVAR_BAD_SIZE) {
rt_vvar_addr = VVAR_BAD_ADDR;
} else {
if (sym_rt->vdso_before_vvar)
rt_vvar_addr += sym_rt->vdso_size;
else
rt_vdso_addr += sym_rt->vvar_size;
}
/*
* Note: we assume that after first migration with inserted
* rt-vdso and trampoilines on the following migrations
@@ -223,8 +202,8 @@ static int add_vdso_proxy(VmaEntry *vma_vdso, VmaEntry *vma_vvar,
* jumps, so we can't remove them if on the following migration
* found that number of symbols in vdso has decreased.
*/
if (vdso_redirect_calls(rt_vdso_addr, vma_vdso->start,
sym_rt, sym_img, compat_vdso)) {
if (vdso_redirect_calls(rt->vdso_start, vma_vdso->start,
&rt->sym, sym_img, compat_vdso)) {
pr_err("Failed to proxify dumpee contents\n");
return -1;
}
@@ -234,16 +213,15 @@ static int add_vdso_proxy(VmaEntry *vma_vdso, VmaEntry *vma_vvar,
* routine we could detect this vdso and do not dump it, since
* it's auto-generated every new session if proxy required.
*/
sys_mprotect((void *)rt_vdso_addr, sym_rt->vdso_size, PROT_WRITE);
vdso_put_mark((void *)rt_vdso_addr, rt_vvar_addr,
vma_vdso->start, orig_vvar_addr);
sys_mprotect((void *)rt_vdso_addr, sym_rt->vdso_size, VDSO_PROT);
sys_mprotect((void *)rt->vdso_start, rt->sym.vdso_size, PROT_WRITE);
vdso_put_mark((void *)rt->vdso_start, rt->vvar_start,
vma_vdso->start, orig_vvar_addr);
sys_mprotect((void *)rt->vdso_start, rt->sym.vdso_size, VDSO_PROT);
return 0;
}
int vdso_proxify(struct vdso_symtable *sym_rt, bool *added_proxy,
unsigned long vdso_rt_parked_at,
int vdso_proxify(struct vdso_maps *rt, bool *added_proxy,
VmaEntry *vmas, size_t nr_vmas,
bool compat_vdso, bool force_trampolines)
{
@@ -291,12 +269,9 @@ int vdso_proxify(struct vdso_symtable *sym_rt, bool *added_proxy,
vma_vvar ? (unsigned long)vma_vvar->end : VVAR_BAD_ADDR);
*added_proxy = false;
if (blobs_matches(vma_vdso, vma_vvar, &s, sym_rt) && !force_trampolines) {
return remap_rt_vdso(vma_vdso, vma_vvar,
sym_rt, vdso_rt_parked_at);
}
if (blobs_matches(vma_vdso, vma_vvar, &s, &rt->sym) && !force_trampolines)
return remap_rt_vdso(vma_vdso, vma_vvar, rt);
*added_proxy = true;
return add_vdso_proxy(vma_vdso, vma_vvar, &s, sym_rt,
vdso_rt_parked_at, compat_vdso);
return add_vdso_proxy(vma_vdso, vma_vvar, &s, rt, compat_vdso);
}

44
criu/pie/restorer.c
View File

@@ -1264,6 +1264,32 @@ static inline int restore_child_subreaper(int child_subreaper)
return 0;
}
static int map_vdso(struct task_restore_args *args, bool compatible)
{
struct vdso_maps *rt = &args->vdso_maps_rt;
int err;
err = arch_map_vdso(args->vdso_rt_parked_at, compatible);
if (err < 0) {
pr_err("Failed to map vdso %d\n", err);
return err;
}
if (rt->sym.vdso_before_vvar) {
rt->vdso_start = args->vdso_rt_parked_at;
/* kernel may provide only vdso */
if (rt->sym.vvar_size != VVAR_BAD_SIZE)
rt->vvar_start = rt->vdso_start + rt->sym.vdso_size;
else
rt->vvar_start = VVAR_BAD_ADDR;
} else {
rt->vvar_start = args->vdso_rt_parked_at;
rt->vdso_start = rt->vvar_start + rt->sym.vvar_size;
}
return 0;
}
/*
* The main routine to restore task via sigreturn.
* This one is very special, we never return there
@@ -1356,15 +1382,8 @@ long __export_restore_task(struct task_restore_args *args)
goto core_restore_end;
/* Map vdso that wasn't parked */
if (args->can_map_vdso) {
int err = arch_map_vdso(args->vdso_rt_parked_at,
args->compatible_mode);
if (err < 0) {
pr_err("Failed to map vdso %d\n", err);
goto core_restore_end;
}
}
if (args->can_map_vdso && (map_vdso(args, args->compatible_mode) < 0))
goto core_restore_end;
/* Shift private vma-s to the left */
for (i = 0; i < args->vmas_n; i++) {
@@ -1496,10 +1515,9 @@ long __export_restore_task(struct task_restore_args *args)
/*
* Proxify vDSO.
*/
if (vdso_proxify(&args->vdso_maps_rt.sym, &has_vdso_proxy,
args->vdso_rt_parked_at,
args->vmas, args->vmas_n, args->compatible_mode,
fault_injected(FI_VDSO_TRAMPOLINES)))
if (vdso_proxify(&args->vdso_maps_rt, &has_vdso_proxy,
args->vmas, args->vmas_n, args->compatible_mode,
fault_injected(FI_VDSO_TRAMPOLINES)))
goto core_restore_end;
/* unmap rt-vdso with restorer blob after restore's finished */