Re: 2.6.25-git2: BUG: unable to handle kernel paging request at ffffffffffffffff

[Jiri Slaby]

On 04/21/2008 10:39 PM, David Miller wrote:
> From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Date: Mon, 21 Apr 2008 09:54:07 -0700 (PDT)
>
> > What I find interesting is that at least for me, I have the SLAB bucket 
> > size for nf_conntrack_expect being 208 bytes. And the *biggest* merge by 
> > far after 2.6.25 so far has been networking (and conntrack in particular)
> >
> > Is that a smoking gun? Not necessarily. But it *is* intriguing. But there 
> > are other possible clashes (the 192-byte bucket has several different 
> > suspects, and not all of them are in networking).1
>
> I think you might be onto something here.
>
> The "mask" member of struct nf_conntrack_expect could be reasonably
> all 1's like the value reported in the crash that begins this
> thread.
>
> Do we know the offset within the object at which this all 1's
> value is found?
>
> My rough calculations show that on 32-bit that expect->mask member is
> at offset 56 and on 64-bit it should be at offset 72.  Does that
> match up to the offset of the filp or whatever bit being corrupted?

dentry.d_name.name is 56 on 64-bit (my memcmp crashes)
dentry.d_hash.next is 24 (crashed at least 3 times here, rafael's one)
dentry.d_op is 136 (crash below)

It's spreading :/.

---------- Forwarded message ----------
From: Zdenek Kabelac <zdenek.kabelac@xxxxxxxxx>
Date: 21.4.2008 11:14
Subject: BUG: unable to handle kernel NULL pointer at d_free+0x18/0x80
To: Kernel development list <linux-kernel@xxxxxxxxxxxxxxx>


Hello

 This oops appeared in my log - unsure how it is related to my DVB-T
 tuner test before.
 But I've also seen another weird resume with some similar crash.

 Happens with 2.6.25 - commit 48a86f548fb74928f9a466f52527e83fecdb4575
 (T61, 2GB)


 BUG: unable to handle kernel NULL pointer dereference at 0000000000000110
 IP: [d_free+24/128] d_free+0x18/0x80
 PGD 0
 Oops: 0000 [1] PREEMPT SMP
 CPU 0
 Modules linked in: usb_storage dvb_usb_af9015 dvb_usb_dibusb_common
 dib3000mc dibx000_common dvb_usb dvb_core tun nls_iso8859_2 nls_cp852
 vfat fat i915 drm ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4
 xt_state nf_conntrack ipt_REJECT xt_tcpudp iptable_filter ip_tables
 x_tables bridge llc nfsd lockd nfs_acl auth_rpcgss exportfs autofs4
 sunrpc binfmt_misc dm_mirror dm_log dm_multipath dm_mod uinput
 kvm_intel kvm snd_hda_intel arc4 ecb snd_seq_oss crypto_blkcipher
 snd_seq_midi_event snd_seq cryptomgr snd_seq_device snd_pcm_oss
 crypto_algapi iwl3945 mac80211 e1000e psmouse snd_mixer_oss rtc_cmos
 evdev rtc_core thinkpad_acpi video snd_pcm mmc_block sdhci mmc_core
 snd_timer iTCO_wdt iTCO_vendor_support battery backlight nvram rtc_lib
 i2c_i801 i2c_core ac snd soundcore snd_page_alloc intel_agp output
 serio_raw cfg80211 button uhci_hcd ohci_hcd ehci_hcd usbcore [last
 unloaded: dvb_core]
 Pid: 210, comm: kswapd0 Not tainted 2.6.25 #56
 RIP: 0010:[d_free+24/128]  [d_free+24/128] d_free+0x18/0x80
 RSP: 0018:ffff81007ced9cf0  EFLAGS: 00010206
 RAX: 00000000000000f0 RBX: ffff8100202723d8 RCX: 0000000000000132
 RDX: 0000000000005e5d RSI: ffff81007ced4048 RDI: ffff8100202723d8
 RBP: ffff81007ced9d00 R08: 0000000000000002 R09: d37a6f4de9bd37a7
 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8100202723d8
 R13: ffff81007c9329d8 R14: ffff8100202723e0 R15: 0000000000000029
 FS:  0000000000000000(0000) GS:ffffffff81486000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
 CR2: 0000000000000110 CR3: 0000000001001000 CR4: 00000000000026e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Process kswapd0 (pid: 210, threadinfo ffff81007ced8000, task ffff81007ced4000)
 Stack:  ffff8100202723d8 ffff81007b7e73d8 ffff81007ced9d20 ffffffff810cb3eb
  ffff8100202723d8 0000000000000000 ffff81007ced9d40 ffffffff810cb4d5
  ffff8100202723d8 ffff8100202723d8 ffff81007ced9d80 ffffffff810cb642
 Call Trace:
  [d_kill+59/96] d_kill+0x3b/0x60
  [prune_one_dentry+197/240] prune_one_dentry+0xc5/0xf0
  [prune_dcache+322/512] prune_dcache+0x142/0x200
  [shrink_dcache_memory+65/80] shrink_dcache_memory+0x41/0x50
  [shrink_slab+274/480] shrink_slab+0x112/0x1e0
  [kswapd+1232/1552] kswapd+0x4d0/0x610
  [isolate_pages_global+0/64] ? isolate_pages_global+0x0/0x40
  [autoremove_wake_function+0/64] ? autoremove_wake_function+0x0/0x40
  [_spin_unlock_irqrestore+69/144] ? _spin_unlock_irqrestore+0x45/0x90
  [kswapd+0/1552] ? kswapd+0x0/0x610
  [kthread+73/144] kthread+0x49/0x90
  [child_rip+10/18] child_rip+0xa/0x12
  [restore_args+0/48] ? restore_args+0x0/0x30
  [kthread+0/144] ? kthread+0x0/0x90
  [child_rip+0/18] ? child_rip+0x0/0x12


 Code: 95 49 81 e8 ab ff 21 00 5b 41 5c c9 c3 66 0f 1f 44 00 00 55 48
 89 e5 53 48 89 fb 48 83 ec 08 48 8b 87 b8 00 00 00 48 85 c0 74 0b <48>
 8b 40 20 48 85 c0 74 02 ff d0 48 83 7b 50 00 74 1e 48 8d bb
 RIP  [d_free+24/128] d_free+0x18/0x80
  RSP <ffff81007ced9cf0>
 CR2: 0000000000000110
 ---[ end trace ca143223eefdc828 ]---
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