Re: GPF in run_workqueue()/list_del_init(cwq->worklist.next) on resume (was: Re: Help needed: Resume problems in 2.6.32-rc, perhaps related to preempt_count leakage in keventd)

Linus Torvalds
2009-11-09T21:43:49Z

On Mon, 9 Nov 2009, Rafael J. Wysocki wrote:
>
> [ 52.013018] general protection fault: 0000 [#1] PREEMPT SMP

It'sa GP fault only because it's an invalid pointer - it's the same as a
NULL pointer page fault, except pointing into the invalid hole in between
low virtual memory and high virtual memory mappings.

> [ 52.013431] last sysfs file: /sys/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.3/ttyUSB3/port_number
> [ 52.013700] CPU 0
> [ 52.013900] Modules linked in: ip6t_LOG af_packet xt_tcpudp xt_pkttype ipt_LOG xt_limit bnep sco rfcomm l2cap crc16 snd_pcm_oss snd_mixer_oss snd_seq binfmt_misc snd_seq_device ip6t_REJECT nf_conntrack_ipv6 ip6table_raw xt_NOTRACK ipt_REJECT xt_state iptable_raw iptable_filter ip6table_mangle nf_conntrack_netbios_ns nf_conntrack_ipv4 cpufreq_conservative nf_conntrack nf_defrag_ipv4 cpufreq_ondemand ip_tables cpufreq_userspace cpufreq_powersave acpi_cpufreq ip6table_filter ip6_tables x_tables freq_table ipv6 microcode fuse loop sr_mod cdrom dm_mod arc4 ecb btusb snd_hda_codec_realtek bluetooth iwlagn snd_hda_intel snd_hda_codec iwlcore pcmcia snd_hwdep snd_pcm sdhci_pci mac80211 snd_timer joydev sdhci toshiba_acpi yenta_socket usbhid cfg80211 snd option rtc_cmos mmc_core firewire_ohci video rsrc_nonstatic psmouse firewire_core backlight soundcore iTCO_wdt rtc_core hid battery ac intel_agp button usb_storage snd_page_alloc usbserial rfkill pcmcia_core iTCO_vendor_support !
e1000e rtc_lib led_class serio_raw crc_itu_t output uinput sg ehci_hcd uhci_hcd sd_mod crc_t10dif usbcore ext3 jbd fan ahci libata thermal processor
> [ 52.016961] Pid: 9, comm: events/0 Not tainted 2.6.32-rc6-tst #160 PORTEGE R500
> [ 52.016961] RIP: 0010:[<ffffffff81054bff>] [<ffffffff81054bff>] worker_thread+0x15b/0x22a
> [ 52.016961] RSP: 0018:ffff88007f0d9e40 EFLAGS: 00010046
> [ 52.016961] RAX: ffff88007e056b68 RBX: ffff88007f09bd48 RCX: 6b6b6b6b6b6b6b6b

The code is

8: ff 13 callq *(%rbx)
a: 48 83 c3 08 add $0x8,%rbx
e: 48 83 3b 00 cmpq $0x0,(%rbx)
12: eb ec jmp 0x0
14: e8 3d ef ff ff callq 0xffffffffffffef56
19: 49 8b 45 08 mov 0x8(%r13),%rax
1d: 4d 89 65 30 mov %r12,0x30(%r13)
21: 4c 89 ef mov %r13,%rdi
24: 48 8b 08 mov (%rax),%rcx
27: 48 8b 50 08 mov 0x8(%rax),%rdx
2b:* 48 89 51 08 mov %rdx,0x8(%rcx) <-- trapping instruction
2f: 48 89 0a mov %rcx,(%rdx)
32: 48 89 40 08 mov %rax,0x8(%rax)

and %rcx is 0x6b6b6b6b6b6b6b6b, which is the POISON_FREE byte sequence.

So somebody is trying to remove a list entry that was already free'd.

Linus