Messages in this thread | | | Date | Fri, 10 May 2019 18:32:58 +0200 | From | Martin Schwidefsky <> | Subject | Re: [PATCH] vsprintf: Do not break early boot with probing addresses |
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On Fri, 10 May 2019 12:24:01 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Fri, 10 May 2019 10:42:13 +0200 > Petr Mladek <pmladek@suse.com> wrote: > > > static const char *check_pointer_msg(const void *ptr) > > { > > - char byte; > > - > > if (!ptr) > > return "(null)"; > > > > - if (probe_kernel_address(ptr, byte)) > > + if ((unsigned long)ptr < PAGE_SIZE || IS_ERR_VALUE(ptr)) > > return "(efault)"; > > > > > < PAGE_SIZE ? > > do you mean: < TASK_SIZE ?
The check with < TASK_SIZE would break on s390. The 'ptr' is in the kernel address space, *not* in the user address space. Remember s390 has two separate address spaces for kernel/user the check < TASK_SIZE only makes sense with a __user pointer.
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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