[PATCH 4.3 003/157] x86/signal: Fix restart_syscall number for x32 tasks
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2016-01-27 18:21:04
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lkml
4.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Dmitry V. Levin" <redacted> 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 <redacted> Signed-off-by: Dmitry V. Levin <redacted> Cc: Elvira Khabirova <redacted> Link: http://lkml.kernel.org/r/20151130215436.GA25996@altlinux.org Signed-off-by: Thomas Gleixner <redacted> 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; }