| From 22eab1108781eff09961ae7001704f7bd8fb1dce Mon Sep 17 00:00:00 2001 |
| From: "Dmitry V. Levin" <ldv@altlinux.org> |
| Date: Tue, 1 Dec 2015 00:54:36 +0300 |
| Subject: x86/signal: Fix restart_syscall number for x32 tasks |
| |
| From: "Dmitry V. Levin" <ldv@altlinux.org> |
| |
| commit 22eab1108781eff09961ae7001704f7bd8fb1dce upstream. |
| |
| 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. This |
| issue has been there since the introduction of x32. |
| |
| Reported-by: strace/tests/restart_syscall.test |
| Reported-and-tested-by: Elvira Khabirova <lineprinter0@gmail.com> |
| Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> |
| Cc: Elvira Khabirova <lineprinter0@gmail.com> |
| Link: http://lkml.kernel.org/r/20151130215436.GA25996@altlinux.org |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/x86/kernel/signal.c | 17 ++++++++++------- |
| 1 file changed, 10 insertions(+), 7 deletions(-) |
| |
| --- a/arch/x86/kernel/signal.c |
| +++ b/arch/x86/kernel/signal.c |
| @@ -688,12 +688,15 @@ handle_signal(struct ksignal *ksig, stru |
| 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 |
| @@ -722,7 +725,7 @@ 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; |
| } |