On Wed, Feb 05, 2014 at 08:39:12AM -0500, Vivek Goyal wrote:
> On Tue, Feb 04, 2014 at 04:25:52PM -0700, Greg Pearson wrote:
>
> [..]
> > diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> > index 2ca7ba0..88d4585 100644
> > --- a/fs/proc/vmcore.c
> > +++ b/fs/proc/vmcore.c
> > @@ -468,17 +468,24 @@ static int __init update_note_header_size_elf64(const
> > Elf64_Ehdr *ehdr_ptr)
> > return rc;
> > }
> > nhdr_ptr = notes_section;
> > - while (real_sz < max_sz) {
> > - if (nhdr_ptr->n_namesz == 0)
> > - break;
> > + while (nhdr_ptr->n_namesz != 0) {
> > sz = sizeof(Elf64_Nhdr) +
> > ((nhdr_ptr->n_namesz + 3) & ~3) +
> > ((nhdr_ptr->n_descsz + 3) & ~3);
> > + if ((real_sz + sz) > max_sz) {
> > + pr_warn("Warning: Exceeded p_memsz, dropping
> > PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
> > + nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
>
> You will need line break in pr_warn(). Too long a line. Limit it 80
> columns per line.
>
> > + break;
> > + }
> > real_sz += sz;
> > nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
> > }
> > kfree(notes_section);
> > phdr_ptr->p_memsz = real_sz;
> > + if (real_sz == 0) {
> > + pr_warn("Warning: Zero PT_NOTE entries found\n");
> > + return -EINVAL;
>
> Given the fact that this is the first time I have heard about a PT_NOTE
> being corrup, I will be fine with this patch too. If one encounters
> an empty PT_NOTE, error out and don't create vmcore.
>
> So please repost this patch with line lenght fixed.
Hi Greg,
Is there any more debugging info on why a PT_NOTE is getting corrupt. Did
you get a chance to debug it further. This patch is more of a band-aid and
real problem is why note is getting corrupted and we need to chase that
down and fix that.
Thanks
Vivek
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