On 11/09, Oleg Nesterov wrote:
>
> Note: TASK_SIZE doesn't look right at least on x86, I think it should
> be replaced by TASK_SIZE_MAX.
> ...
> --- x/arch/x86/kernel/hw_breakpoint.c
> +++ x/arch/x86/kernel/hw_breakpoint.c
> @@ -200,7 +200,7 @@ int arch_check_bp_in_kernelspace(struct
> va = info->address;
> len = get_hbp_len(info->len);
>
> - return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);
> + return (va >= TASK_SIZE) || ((va + len - 1) >= TASK_SIZE);
But actully I'd like to ask another question.
Can't we add the additional !in_gate_area_no_mm() check to allow
the hw breakpoints in vsyscall?
Quoting Amnon:
My service needs to catch the system-calls of its traced son.
Almost all system-calls are caught with PTRACE_SYSCALL, but not those
using the vsyscall page - especially "gettimeofday()" and "time()".
...
However, the code in "arch/x86/kernel/ptrace.c" forbids catching kernel
addresses.
I tend to agree with Amnon...
What do you think?
Oleg.
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