ia32/futex: restore compat_robust_list

The same as for Checkpointing - we need to call 32-bit syscall
for compatible tasks here to correctly restore compat_robust_list,
not robust_list.

Note: I check here restorer's *task* arg for compatible mode, not
restorer *thread* arg. As changing application's mode during runtime
is very rare thing itself, application that runs different bitness
threads is most likely not present at all.
If we ever meet such application, this could be improved.
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/arch/aarch64/include/asm/restorer.h

@@ -64,7 +64,13 @@ static inline void restore_tls(tls_t *ptls)
 
 static inline void *alloc_compat_syscall_stack(void) { return NULL; }
 static inline void free_compat_syscall_stack(void *stack32) { }
-static inline int
-arch_compat_rt_sigaction(void *stack, int sig, void *act) { return -1; }
+static inline int arch_compat_rt_sigaction(void *stack, int sig, void *act)
+{
+	return -1;
+}
+static inline int set_compat_robust_list(uint32_t head_ptr, uint32_t len)
+{
+	return -1;
+}
 
 #endif

criu/arch/arm/include/asm/restorer.h

@@ -77,7 +77,13 @@ static inline void restore_tls(tls_t *ptls) {
 
 static inline void *alloc_compat_syscall_stack(void) { return NULL; }
 static inline void free_compat_syscall_stack(void *stack32) { }
-static inline int
-arch_compat_rt_sigaction(void *stack, int sig, void *act) { return -1; }
+static inline int arch_compat_rt_sigaction(void *stack, int sig, void *act)
+{
+	return -1;
+}
+static inline int set_compat_robust_list(uint32_t head_ptr, uint32_t len)
+{
+	return -1;
+}
 
 #endif

criu/arch/ppc64/include/asm/restorer.h

@@ -63,7 +63,13 @@ unsigned long sys_shmat(int shmid, const void *shmaddr, int shmflg);
 
 static inline void *alloc_compat_syscall_stack(void) { return NULL; }
 static inline void free_compat_syscall_stack(void *stack32) { }
-static inline int
-arch_compat_rt_sigaction(void *stack, int sig, void *act) { return -1; }
+static inline int arch_compat_rt_sigaction(void *stack, int sig, void *act)
+{
+	return -1;
+}
+static inline int set_compat_robust_list(uint32_t head_ptr, uint32_t len)
+{
+	return -1;
+}
 
 #endif /*__CR_ASM_RESTORER_H__*/

criu/arch/x86/crtools.c

@@ -438,21 +438,6 @@ int restore_gpregs(struct rt_sigframe *f, UserX86RegsEntry *r)
 	return 0;
 }
 
-struct syscall_args32 {
-	uint32_t nr, arg0, arg1, arg2, arg3, arg4, arg5;
-};
-
-static void do_full_int80(struct syscall_args32 *args)
-{
-	register unsigned long bp asm("bp") = args->arg5;
-	asm volatile ("int $0x80"
-		      : "+a" (args->nr),
-			"+b" (args->arg0), "+c" (args->arg1), "+d" (args->arg2),
-			"+S" (args->arg3), "+D" (args->arg4), "+r" (bp)
-			: : "r8", "r9", "r10", "r11");
-	args->arg5 = bp;
-}
-
 static int get_robust_list32(pid_t pid, uintptr_t head, uintptr_t len)
 {
 	struct syscall_args32 s = {

criu/arch/x86/include/asm/compat.h

@@ -34,6 +34,22 @@ static inline void free_compat_syscall_stack(void *mem)
 				mem, ret);
 }
 
+struct syscall_args32 {
+	uint32_t nr, arg0, arg1, arg2, arg3, arg4, arg5;
+};
+
+static inline void do_full_int80(struct syscall_args32 *args)
+{
+	register unsigned long bp asm("bp") = args->arg5;
+	asm volatile ("int $0x80"
+		      : "+a" (args->nr),
+			"+b" (args->arg0), "+c" (args->arg1), "+d" (args->arg2),
+			"+S" (args->arg3), "+D" (args->arg4), "+r" (bp)
+			: : "r8", "r9", "r10", "r11");
+	args->arg5 = bp;
+}
+
+
 #ifdef CONFIG_COMPAT
 extern unsigned long call32_from_64(void *stack, void *func);
 #endif

criu/arch/x86/include/asm/restorer.h

@@ -12,10 +12,17 @@
 extern void restore_tls(tls_t *ptls);
 extern int arch_compat_rt_sigaction(void *stack32, int sig,
 		rt_sigaction_t_compat *act);
+extern int set_compat_robust_list(uint32_t head_ptr, uint32_t len);
 #else /* CONFIG_COMPAT */
 static inline void restore_tls(tls_t *ptls) { }
-static inline int
-arch_compat_rt_sigaction(void *stack, int sig, void *act) { return -1; }
+static inline int arch_compat_rt_sigaction(void *stack, int sig, void *act)
+{
+	return -1;
+}
+static inline int set_compat_robust_list(uint32_t head_ptr, uint32_t len)
+{
+	return -1;
+}
 #endif /* !CONFIG_COMPAT */
 
 #define RUN_CLONE_RESTORE_FN(ret, clone_flags, new_sp, parent_tid,      \

criu/arch/x86/restorer.c

@@ -3,9 +3,11 @@
 
 #include "types.h"
 #include "restorer.h"
+#include "asm/compat.h"
 #include "asm/restorer.h"
 #include <compel/asm/fpu.h>
 
+#include <compel/plugins/std/syscall-codes.h>
 #include <compel/plugins/std/string.h>
 #include <compel/plugins/std/syscall.h>
 #include "log.h"
@@ -34,6 +36,18 @@ int restore_nonsigframe_gpregs(UserX86RegsEntry *r)
 
 #ifdef CONFIG_COMPAT
 
+int set_compat_robust_list(uint32_t head_ptr, uint32_t len)
+{
+	struct syscall_args32 s = {
+		.nr	= __NR32_set_robust_list,
+		.arg0	= head_ptr,
+		.arg1	= len,
+	};
+
+	do_full_int80(&s);
+	return (int)s.nr;
+}
+
 static int prepare_stack32(void **stack32)
 {
 	if (*stack32)

criu/pie/restorer.c

@@ -422,21 +422,41 @@ die:
 	return -1;
 }
 
-static int restore_thread_common(struct thread_restore_args *args)
+static int restore_robust_futex(struct thread_restore_args *args)
 {
-	sys_set_tid_address((int *)decode_pointer(args->clear_tid_addr));
+	uint32_t futex_len = args->futex_rla_len;
+	int ret;
 
-	if (args->futex_rla_len) {
-		int ret;
+	if (!args->futex_rla_len)
+		return 0;
 
-		ret = sys_set_robust_list(decode_pointer(args->futex_rla),
-					  args->futex_rla_len);
-		if (ret) {
-			pr_err("Failed to recover futex robust list: %d\n", ret);
-			return -1;
-		}
+	/*
+	 * XXX: We check here *task's* mode, not *thread's*.
+	 * But it's possible to write an application with mixed
+	 * threads (on x86): some in 32-bit mode, some in 64-bit.
+	 * Quite unlikely that such application exists at all.
+	 */
+	if (args->ta->compatible_mode) {
+		uint32_t futex = (uint32_t)args->futex_rla;
+		ret = set_compat_robust_list(futex, futex_len);
+	} else {
+		void *futex = decode_pointer(args->futex_rla);
+		ret = sys_set_robust_list(futex, futex_len);
 	}
 
+	if (ret)
+		pr_err("Failed to recover futex robust list: %d\n", ret);
+
+	return ret;
+}
+
+static int restore_thread_common(struct thread_restore_args *args)
+{
+	sys_set_tid_address((int *)decode_pointer(args->clear_tid_addr));
+
+	if (restore_robust_futex(args))
+		return -1;
+
 	restore_sched_info(&args->sp);
 
 	if (restore_nonsigframe_gpregs(&args->gpregs))