When restarting a syscall with regs->ax == -ERESTART_RESTARTBLOCK,
regs->ax is assigned to a restart_syscall number. For x32 tasks,
this syscall number must have __X32_SYSCALL_BIT set, otherwise it
will be an x86_64 syscall number instead of a valid x32 syscall number.
Reported-by: strace/tests/restart_syscall.test
Reported-and-tested-by: Elvira Khabirova <lineprint...@gmail.com>
Signed-off-by: Dmitry V. Levin <l...@altlinux.org>
Cc: sta...@vger.kernel.org
---
arch/x86/kernel/signal.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index b7ffb7c..cb6282c 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -690,12 +690,15 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
signal_setup_done(failed, ksig, stepping);
}
-#ifdef CONFIG_X86_32
-#define NR_restart_syscall __NR_restart_syscall
-#else /* !CONFIG_X86_32 */
-#define NR_restart_syscall \
- test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall :
__NR_restart_syscall
-#endif /* CONFIG_X86_32 */
+static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
+{
+#if defined(CONFIG_X86_32) || !defined(CONFIG_X86_64)
+ return __NR_restart_syscall;
+#else /* !CONFIG_X86_32 && CONFIG_X86_64 */
+ return test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall :
+ __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
+#endif /* CONFIG_X86_32 || !CONFIG_X86_64 */
+}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
@@ -724,7 +727,7 @@ void do_signal(struct pt_regs *regs)
break;
case -ERESTART_RESTARTBLOCK:
- regs->ax = NR_restart_syscall;
+ regs->ax = get_nr_restart_syscall(regs);
regs->ip -= 2;
break;
}
--
ldv
--
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