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

From: Ben Castricum
Date: Sun Oct 19 2008 - 14:50:30 EST

On Sun, 19 Oct 2008, Hugh Dickins wrote:

Isn't it the issue fixed by

I am not sure, below is the latest bug message. My knowledge of git is very limited, how can I tell if this is before or after the patch?


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 n
f_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_i80
1 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)
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 c
3 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 ]---

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