Re: OOPS: 2.6.24-rc5-mm1 -- EIP is at r_show+0x2a/0x70 -- (triggered by "cat /proc/iomem")

From: Alexey Dobriyan
Date: Thu Dec 20 2007 - 05:54:21 EST


> > > Okay. The command that directly triggers this is: cat /proc/iomem

> > > [ 252.868386] BUG: unable to handle kernel NULL pointer dereference at virtual address 00000018

> > > [ 252.868481] EIP is at r_show+0x2a/0x70
> > > [ 252.868483] EAX: 00000000 EBX: 00000001 ECX: c07e3224 EDX: c04bb034
> > > [ 252.868486] ESI: 00000008 EDI: ed1f52c0 EBP: f5320f10 ESP: f5320f04
> > > [ 252.868489] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
> > > [ 252.868493] Process head (pid: 7088, ti=f5320000 task=f532e000 task.ti=f5320000)

> > > [ 252.868552] [<c0199a7e>] seq_read+0x19a/0x26c
> > > [ 252.868557] [<c01af4f5>] proc_reg_read+0x60/0x74
> > > [ 252.868562] [<c018390d>] vfs_read+0xa2/0x11e
> > > [ 252.868567] [<c0183d02>] sys_read+0x3b/0x60
> > > [ 252.868571] [<c0106bae>] sysenter_past_esp+0x6b/0xc1
> > > [ 252.868575] =======================
> > > [ 252.868577] Code: c3 55 89 d1 89 e5 57 89 c7 56 53 8b 50 64 83 7a
> > > 0c 00 77 0e 81 7a 08 ff ff 00 00 be 04 00 00 00 76 05 be 08 00 00 00
> > > 89 c8 31 db <8b> 40 18 39 d0 74 06 43 83 fb 05 75 f3 8b 41 10 ba 2f 1b
> > > 45 c0
> > > [ 252.868623] EIP: [<c012d527>] r_show+0x2a/0x70 SS:ESP 0068:f5320f04
> > >
> > >
>
> I would be suspecting iget-stop-procfs-from-using-iget-and-read_inode.patch.

Something is screwed in resources tree?
Miles, you have CONFIG_RESOURCES_64BIT=y, right?

<r_show>:
55 push %ebp
89 d1 mov %edx,%ecx
89 e5 mov %esp,%ebp
57 push %edi
89 c7 mov %eax,%edi
56 push %esi
53 push %ebx
8b 50 64 mov 0x64(%eax),%edx
83 7a 0c 00 cmpl $0x0,0xc(%edx)
77 0e ja 1f
81 7a 08 ff ff 00 00 cmpl $0000ffff,0x8(%edx)
be 04 00 00 00 mov $0x4,%esi # width = 4
76 05 jbe 2f
1: be 08 00 00 00 mov $0x8,%esi # width = 8
2: 89 c8 mov %ecx,%eax # %eax = p
31 db xor %ebx,%ebx # depth = 0
4:===> <8b> 40 18 mov 0x18(%eax),%eax # p = p->parent
39 d0 cmp %edx,%eax # if (p->parent == root)
74 06 je 3f
43 inc %ebx depth++
83 fb 05 cmp $0x5,%ebx depth < MAX_IORES_LEVEL
75 f3 jne 4b
3: 8b 41 10 mov 0x10(%ecx),%eax
ba 2f 1b 45 c0 mov $c0451b2f,%edx
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