Messages in this thread | | | Subject | Re: [RFC patch] vsprintf: Add %pav extension for print_vma_addr | From | Joe Perches <> | Date | Wed, 27 May 2015 14:09:31 -0700 |
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On Wed, 2015-05-27 at 14:04 -0700, Andrew Morton wrote: > On Tue, 26 May 2015 16:05:04 -0700 Joe Perches <joe@perches.com> wrote: > > print_vma_addr is another function to emit useful > > data similar to print_symbol. The print_symbol > > functionality has been added via %p[fFsS] vsprintf > > extensions. > > > > Perhaps it's appropriate to add vma_addr address > > decoding to vsprintf too. [] > > static noinline_for_stack > > +char *vma_addr(char *buf, char *end, const void *addr, > > + struct printf_spec spec, const char *fmt) > > +{ > > + struct mm_struct *mm = current->mm; > > + struct vm_area_struct *vma; > > + unsigned long ip = *(unsigned long *)addr; > > + char *rtn; > > + > > + /* if we are in atomic contexts (in exception stacks, etc.) */ > > + if (preempt_count()) > > + return string(buf, end, "(atomic context)", spec); > > Problems when CONFIG_PREEMPT=n. > > > + down_read(&mm->mmap_sem); > > + vma = find_vma(mm, ip); > > + if (vma && vma->vm_file) { > > + struct file *f = vma->vm_file; > > + char *gfp_buf = (char *)__get_free_page(GFP_KERNEL); > > We shouldn't assume we can use GFP_KERNEL here. Even if the > preempt_count() worked, we might be in a context which requires > GFP_NOFS or GFP_NOIO.
This code is basically a copy of the existing print_vma_addr() so is that true for all the existing uses too?
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