Bug#723180: linux-image-3.2.0-4-rt-amd64: kernel oops with futexes and gdb reverse-next

[Brian Silverman <bsilver.debian@gmail.com>]

I can see (and download) them both at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=723180. I'm just going to paste the backtrace in here, but that won't work for the executable, and I'm not sure what to do differently to get the attachments to work right.

Also, I forgot to mention before: if it would help, I'd be happy to send the source code for the executable. I can also give details of how my code is misusing futexes once I figure that out.

Here's the stacktrace:

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445219] CPU 2 

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445220] Modules linked in: aes_x86_64 aes_generic parport_pc ppdev lp parport bnep rfcomm cpufreq_stats cpufreq_userspace cpufreq_conservative cpufreq_powersave binfmt_misc uinput fuse nfsd nfs nfs_acl auth_rpcgss fscache lockd sunrpc ext2 mbcache loop kvm_intel kvm uvcvideo videodev v4l2_compat_ioctl32 media arc4 snd_hda_codec_hdmi joydev btusb snd_hda_codec_realtek bluetooth crc16 iwlwifi coretemp i915 snd_hda_intel snd_hda_codec drm_kms_helper snd_hwdep drm snd_pcm snd_page_alloc snd_seq i2c_algo_bit snd_seq_device i2c_i801 dell_wmi snd_timer psmouse sparse_keymap serio_raw acpi_cpufreq mperf dell_laptop mac80211 cfg80211 crc32c_intel snd dcdbas i2c_core ghash_clmulni_intel wmi iTCO_wdt iTCO_vendor_support video evdev soundcore rfkill pcspkr ac battery power_supply cryptd processor button xfs dm_mod sg sr_mod sd_mod cdrom crc_t10dif usbhid hid thermal thermal_sys ahci libahci libata scsi_mod r8169 xhci_hcd mii ehci_hcd usbcore usb_common [last unloaded: scsi_wait_scan]

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445277] 

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445279] Pid: 13661, comm: mutex_test Not tainted 3.2.0-4-rt-amd64 #1 Debian 3.2.46-1+deb7u1 Dell Inc.          Dell System Inspiron N4110/05TM8C

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445283] RIP: 0010:[<ffffffff81368e30>]  [<ffffffff81368e30>] native_irq_enable_sysexit+0x10/0x10

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445289] RSP: 0018:0000000000000000  EFLAGS: 00010146

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445291] RAX: 00000000000000e0 RBX: 00000000f7d06cd4 RCX: 000000000d696910

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445293] RDX: 00000000ffffcd94 RSI: 00000000f7fe8da6 RDI: 00000000f7d13a30

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445295] RBP: 00000000ffffcd2c R08: 0000000000000000 R09: 0000000000000000

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445296] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445298] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445300] FS:  0000000000000000(0000) GS:ffff88013f100000(0063) knlGS:00000000f7cff700

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445302] CS:  0010 DS: 002b ES: 002b CR0: 000000008005003b

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445304] CR2: fffffffffffffff8 CR3: 00000000a669a000 CR4: 00000000000406e0

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445306] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445308] DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445310] Process mutex_test (pid: 13661, threadinfo ffff8800745ac000, task ffff880135b42440)

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445312]  ffff88013f105e40 ffffffff81621298 0000000000000000 ffff88013f105f58

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445316]  0000000000000000 0000000000000ac0 0000000000000000 0000000000000040

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445318]  ffffffff81010d8b ffff880135b42440 ffffffffffffffff ffff88013f105eb8

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445327]  [<ffffffff81010d8b>] ? show_registers+0xac/0x209

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445331]  [<ffffffff8136325b>] ? __die+0x99/0xd6

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445333]  [<ffffffff81011a28>] ? die+0x3f/0x5b

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445336]  [<ffffffff8100fc75>] ? do_double_fault+0x5a/0x5c

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445338]  [<ffffffff81368a75>] ? double_fault+0x25/0x30

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445341]  [<ffffffff81368e30>] ? native_irq_enable_sysexit+0x10/0x10

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.445367]  RSP <0000000000000000>

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.512886] ---[ end trace 0000000000000002 ]---

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513030] ------------[ cut here ]------------

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513036] WARNING: at /build/linux-iWNI5S/linux-3.2.46/debian/build/source_rt/kernel/smp.c:325 smp_call_function_single+0x75/0x12e()

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513038] Hardware name: Dell System Inspiron N4110

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513039] Modules linked in: aes_x86_64 aes_generic parport_pc ppdev lp parport bnep rfcomm cpufreq_stats cpufreq_userspace cpufreq_conservative cpufreq_powersave binfmt_misc uinput fuse nfsd nfs nfs_acl auth_rpcgss fscache lockd sunrpc ext2 mbcache loop kvm_intel kvm uvcvideo videodev v4l2_compat_ioctl32 media arc4 snd_hda_codec_hdmi joydev btusb snd_hda_codec_realtek bluetooth crc16 iwlwifi coretemp i915 snd_hda_intel snd_hda_codec drm_kms_helper snd_hwdep drm snd_pcm snd_page_alloc snd_seq i2c_algo_bit snd_seq_device i2c_i801 dell_wmi snd_timer psmouse sparse_keymap serio_raw acpi_cpufreq mperf dell_laptop mac80211 cfg80211 crc32c_intel snd dcdbas i2c_core ghash_clmulni_intel wmi iTCO_wdt iTCO_vendor_support video evdev soundcore rfkill pcspkr ac battery power_supply cryptd processor button xfs dm_mod sg sr_mod sd_mod cdrom crc_t10dif usbhid hid thermal thermal_sys ahci libahci libata scsi_mod r8169 xhci_hcd mii ehci_hcd usbcore usb_common [last unloaded: scsi_wait_scan]

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513086] Pid: 13661, comm: mutex_test Tainted: G      D      3.2.0-4-rt-amd64 #1 Debian 3.2.46-1+deb7u1

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513088] Call Trace:

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513090]  <#DF>  [<ffffffff81048b6f>] ? warn_slowpath_common+0x78/0x8c

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513097]  [<ffffffff810b4c78>] ? perf_exclude_event.part.17+0x31/0x31

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513099]  [<ffffffff810753d3>] ? smp_call_function_single+0x75/0x12e

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513102]  [<ffffffff810b3a1d>] ? task_function_call+0x42/0x4c

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513105]  [<ffffffff810b792a>] ? perf_cgroup_switch+0x13b/0x13b

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513108]  [<ffffffff8108a45d>] ? cgroup_exit+0xb4/0xe6

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513110]  [<ffffffff8104c448>] ? do_exit+0x2c1/0x774

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513113]  [<ffffffff813624ad>] ? _raw_spin_unlock_irqrestore+0x2e/0x3c

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513116]  [<ffffffff8104a2dc>] ? kmsg_dump+0x95/0xf5

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513118]  [<ffffffff813631bd>] ? oops_end+0xb1/0xb6

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513122]  [<ffffffff8100fc75>] ? do_double_fault+0x5a/0x5c

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513124]  [<ffffffff81368a75>] ? double_fault+0x25/0x30

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513127]  [<ffffffff81368e30>] ? native_irq_enable_sysexit+0x10/0x10

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513129]  <<EOE>> 

Sep 16 22:14:41 dell-inspiron-linux kernel: [250336.513130] ---[ end trace 0000000000000003 ]---

I saw this in the log afterwards too (probably just a result of the kernel oops, but I'm not sure):

Sep 16 22:17:42 dell-inspiron-linux kernel: [250517.113424] Watchdog[29590]: segfault at 0 ip 00007ff090932afe sp 00007ff0838f7560 error 6 in chrome[7ff08e067000+57c2000]

Sep 16 22:17:56 dell-inspiron-linux kernel: [250531.187581] Watchdog[13678]: segfault at 0 ip 00007fe8a350fafe sp 00007fe8964d4560 error 6 in chrome[7fe8a0c44000+57c2000]

After all of that, I can see from the logs that everything was still working enough to recognize the USB flash drive that I plugged in to boot off of. Impressive...

On Tue, Sep 17, 2013 at 7:17 AM, Ben Hutchings <ben@decadent.org.uk> wrote:

On Mon, 2013-09-16 at 23:13 -0700, Brian Silverman wrote:
> Package: src:linux
> Version: 3.2.46-1+deb7u1
> Severity: normal
>
> I was working on some custom mutex code (implemented using futexes), and
> it wasn't working, so I started it up under GDB, waited until
> it died, and then tried reverse stepping back to where it did something
> wrong. I then got a kernel oops.
>
> Here's exactly what I did:
> In GDB, I set up a breakpoint in the thread which dies before the
> point at which it dies, `run`, `record`, `cont`, and then (after it
> crashed) `reverse-next` (might have been `reverse-step`). My X11 server
> then went down and dropped me back at a virtual terminal with a kernel
> backtrace on it.
>
> I know that there is a bug in the way that the code
> uses futexes, but it shouldn't lead to a kernel oops...

Indeed.

> I'm attaching
> both the program that causes this problem (it's compiled for amd64 with
> -m32) and the kernel backtrace.

[...]

The attachments didn't arrive; please try again.

Ben.

--
Ben Hutchings
The two most common things in the universe are hydrogen and stupidity.