Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 7 Dec 2015 15:22:06 -0800 | Subject | Re: [PATCH] x86/signal: fix restart_syscall number for x32 tasks |
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[not real reply because I'm using a bad internet connection right now and I'm not set up with my usual Gmane reply hack right now]
The new code is (whitespace-damaged):
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 */ }
This is IMO awful. This use of TIF_IA32 is wrong, and this is otherwise gross. Can we do it for real:
if (is_ia32_task()) return __NR_ia32_restart_syscall; else return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT); /* preserve x32 bit */
I'd send the patch myself, but you apparently have a good test case for this, and I don't.
(this isn't a regression, and I'm not suggesting any change for 4.4 or for stable. But for 4.5, can we do it right, please?)
And yes, I'll send a patch to rename is_ia32_task, but that's orthogonal.
--Andy
P.S. I'm still hoping to kill TIF_IA32 entirely some time soon.
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