Re: NULL pointer derefence since 2.6.27 in (e)poll

[Hugh Dickins]

On Sun, 19 Oct 2008, Pekka Enberg wrote:
> On Sun, Oct 19, 2008 at 2:02 PM, Ben Castricum <lk0810@xxxxxxxxxxxxxxx> wrote:
> > I am getting this bug reports almost daily since about 2.6.27. I saved the
> > output of all of them, but they are all nearly identical, so I just included
> > the first one. After the report networking seems unstable and the system
> > requires a reboot.
> >
> > My .config can be found at http://www.bencastricum.nl/.config
> >
> > I hope this helps.
> >
> > Ben
> >
> >
> > BUG: unable to handle kernel NULL pointer dereference at 00000020
> > IP: [<b0254b74>] sock_poll+0xc/0x12
> > *pde = 00000000
> > Oops: 0000 [#1] SMP
> > last sysfs file:
> > /sys/devices/pci0000:00/0000:00:1f.3/i2c-adapter/i2c-0/0-002e/cpu0_vid
> > Modules linked in: ipt_MASQUERADE ipt_REJECT ipt_LOG xt_recent xt_tcpudp
> > xt_state iptable_filter nf_conntrack_ftp iptable_nat ip_tables nf_nat
> > x_tables nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 af_packet usb_storage
> > usbhid 8139too mii tg3 libphy cdc_acm ehci_hcd uhci_hcd usbcore lm85
> > hwmon_vid i2c_i801 softdog rtc ext2 [last unloaded: firmware_class]
> >
> > Pid: 1717, comm: squid Not tainted (2.6.27-05178-g2e532d6 #111) HP d530
> > SFF(PL110ES)
> > EIP: 0060:[<b0254b74>] EFLAGS: 00010246 CPU: 0
> > EIP is at sock_poll+0xc/0x12
> > EAX: ea872d80 EBX: 00000000 ECX: 00000000 EDX: eee50e00
> > ESI: e9a9bf00 EDI: ef304b80 EBP: ea84af44 ESP: ea84af40
> > DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
> > Process squid (pid: 1717, ti=ea84a000 task=ea96e330 task.ti=ea84a000)
> > Stack:
> > e9a9bf0c ea84afb0 b017ff04 ea84af9c 00000002 00000000 eabe1300 ef304b98
> > 00000003 ef304bac ef304ba4 e9a9bf0c ef304ba0 ef304b94 00000046 ef304b84
> > ea84af9c b03ce000 b014248d ea84af94 b0126765 ea84afb0 b0105909 ea84af9c
> > Call Trace:
> > [<b017ff04>] ? sys_epoll_wait+0x245/0x3a7
> > [<b014248d>] ? handle_fasteoi_irq+0x0/0xad
> > [<b0126765>] ? irq_exit+0x53/0x77
> > [<b0105909>] ? do_IRQ+0xae/0xc4
> > [<b0103905>] ? sysenter_do_call+0x12/0x25
> > Code: 8b 58 54 b8 ea ff ff ff 85 db 74 0c ff 75 0c ff 75 08 89 f0 ff d3 5a
> > 59 8d 65 f8 5b 5e 5d c3 55 89 e5 53 89 d1 8b 50 6c 8b 5a 0c <ff> 53 20 5b 5d
> > c3 55 89 e5 53 89 d1 8b 50 6c 8b 5a 0c ff 53 4c
> > EIP: [<b0254b74>] sock_poll+0xc/0x12 SS:ESP 0068:ea84af40
> > ---[ end trace 6e50fb78d788d751 ]---
> 
> Looks like file->private is NULL in sock_poll() so I'm cc'ing netdev.

Isn't it the issue fixed by

http://marc.info/?l=linux-kernel&m=122428548613067&w=2

Hugh
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