Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 11 Jul 2012 12:10:12 -0700 | Subject | Re: 3.5-rc6 dentry related GPF |
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On Wed, Jul 11, 2012 at 11:32 AM, Dave Jones <davej@redhat.com> wrote: > > What's puzzling me though is how we got from do_dentry_open to try_module_get ?
It's the
f->f_op = fops_get(inode->i_fop);
that does it.
I have no idea what the actual bug is, though, but the code decodes to
0: 89 75 f0 mov %esi,-0x10(%rbp) 3: 4c 89 7d f8 mov %r15,-0x8(%rbp) 7: 66 66 66 66 90 data32 data32 data32 xchg %ax,%ax c: b8 01 00 00 00 mov $0x1,%eax 11: 48 85 ff test %rdi,%rdi 14: 48 89 fb mov %rdi,%rbx 17: 74 42 je 0x5b 19: 65 48 8b 04 25 b0 c8 mov %gs:0xc8b0,%rax 20: 00 00 22: 83 80 44 e0 ff ff 01 addl $0x1,-0x1fbc(%rax) 29:* 83 3f 02 cmpl $0x2,(%rdi) <-- trapping instruction 2c: 0f 84 54 01 00 00 je 0x186 32: 48 8b 87 50 02 00 00 mov 0x250(%rdi),%rax 39: 65 48 ff 00 incq %gs:(%rax)
where that "cmpl $2" is the "module_is_live(module)" test, as far as I can tell. And %rdi should be the module pointer, but it is obviously garbage:
rdi = 54415541e5894855
which looks like some odd corrupted ASCII to me ("UH\211\345AUAT") but that makes no sense either.
Linus
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