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Groups > linux.kernel > #1507264 > unrolled thread

BUG: unable to handle kernel NULL pointer dereference at 00000000000001e0

Started byBorislav Petkov <bp@alien8.de>
First post2016-10-24 16:50 +0200
Last post2016-10-25 03:50 +0200
Articles 5 — 4 participants

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  BUG: unable to handle kernel NULL pointer dereference at  00000000000001e0 Borislav Petkov <bp@alien8.de> - 2016-10-24 16:50 +0200
    Re: BUG: unable to handle kernel NULL pointer dereference at  00000000000001e0 Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-10-24 17:20 +0200
    Re: BUG: unable to handle kernel NULL pointer dereference at  00000000000001e0 Jiri Slaby <jslaby@suse.cz> - 2016-10-24 17:30 +0200
      Re: BUG: unable to handle kernel NULL pointer dereference at  00000000000001e0 Borislav Petkov <bp@alien8.de> - 2016-10-24 21:00 +0200
      Re: BUG: unable to handle kernel NULL pointer dereference at  00000000000001e0 Mike Galbraith <mgalbraith@suse.de> - 2016-10-25 03:50 +0200

#1507264 — BUG: unable to handle kernel NULL pointer dereference at 00000000000001e0

FromBorislav Petkov <bp@alien8.de>
Date2016-10-24 16:50 +0200
SubjectBUG: unable to handle kernel NULL pointer dereference at 00000000000001e0
Message-ID<svOJA-qi-37@gated-at.bofh.it>
Hi people,

typing "reboot" splats the following on the serial console. Ideas?

INIT: Sending p[  427.863916] BUG: unable to handle kernel NULL pointer dereference at 00000000000001e0
[  427.885156] IP: [<ffffffffa24bfb6c>] tty_wakeup+0xc/0x70
[  427.898337] PGD 0 [  427.902051] 
[  427.907498] Oops: 0000 [#1] PREEMPT SMP
[  427.917635] Modules linked in: nfsv3 nfs_acl nfs fscache lockd sunrpc grace edd af_packet cpufreq_conservative cpufreq_userspace cpufreq_powersave fuse loop md_mod dm_mod joydev hid_generic usbhid ipmi_ssif ohci_pci ohci_hcd ehci_pci ehci_hcd e1000e ptp firewire_ohci edac_core pps_core tpm_infineon sp5100_tco firewire_core acpi_cpufreq serio_raw pcspkr fjes usbcore shpchp edac_mce_amd tpm_tis ipmi_si tpm_tis_core i2c_piix4 k10temp sg ipmi_msghandler tpm sr_mod button cdrom kvm_amd kvm irqbypass crc_itu_t ast ttm drm_kms_helper drm fb_sys_fops sysimgblt sysfillrect syscopyarea i2c_algo_bit scsi_dh_rdac scsi_dh_alua scsi_dh_emc scsi_dh_hp_sw ata_generic pata_atiixp
[  428.054179] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc1-1.g73e3f23-default #1
[  428.072868] Hardware name: System manufacturer System Product Name/KGP(M)E-D16, BIOS 0902    12/03/2010
[  428.094755] task: ffffffffa2c0d500 task.stack: ffffffffa2c00000
[  428.109717] RIP: 0010:[<ffffffffa24bfb6c>]  [<ffffffffa24bfb6c>] tty_wakeup+0xc/0x70
[  428.128407] RSP: 0018:ffff9a1a5fc03df8  EFLAGS: 00010086
[  428.142184] RAX: ffff9a1857258000 RBX: ffffffffa3050ea0 RCX: 0000000000000000
[  428.159649] RDX: 000000000000001b RSI: 0000000000000000 RDI: 0000000000000000
[  428.177109] RBP: ffff9a1a5fc03e08 R08: 0000000000000000 R09: 0000000000000000
[  428.194547] R10: 0000000000021c77 R11: 0000000000000000 R12: ffff9a1857258000
[  428.212002] R13: 0000000000000000 R14: 0000000000000020 R15: 0000000000000020
[  428.229481] FS:  0000000000000000(0000) GS:ffff9a1a5fc00000(0000) knlGS:0000000000000000
[  428.248938] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  428.263726] CR2: 00000000000001e0 CR3: 0000000390c06000 CR4: 00000000000006f0
[  428.281331] Stack:
[  428.288696]  ffffffffa3050ea0 ffff9a1857258000 ffff9a1a5fc03e18 ffffffffa24e0ab1
[  428.307064]  ffff9a1a5fc03e40 ffffffffa24e8865 ffffffffa3050ea0 00000000000000c2
[  428.325456]  0000000000000046 ffff9a1a5fc03e78 ffffffffa24e8a5f ffffffffa3050ea0
[  428.343905] Call Trace:
[  428.352319]  <IRQ> [  428.356216]  [<ffffffffa24e0ab1>] uart_write_wakeup+0x21/0x30
[  428.371337]  [<ffffffffa24e8865>] serial8250_tx_chars+0x225/0x240
[  428.387182]  [<ffffffffa24e8a5f>] serial8250_handle_irq.part.21+0xdf/0xf0
[  428.404405]  [<ffffffffa24e8ad7>] serial8250_default_handle_irq+0x47/0x70
[  428.421603]  [<ffffffffa24e4023>] serial8250_interrupt+0x63/0x120
[  428.437398]  [<ffffffffa20e0521>] __handle_irq_event_percpu+0x81/0x1d0
[  428.454024]  [<ffffffffa20e0693>] handle_irq_event_percpu+0x23/0x60
[  428.470091]  [<ffffffffa20e070c>] handle_irq_event+0x3c/0x60
[  428.484900]  [<ffffffffa20e3d10>] handle_edge_irq+0x80/0x150
[  428.499687]  [<ffffffffa20312ad>] handle_irq+0x1d/0x30
[  428.513458]  [<ffffffffa271c22b>] do_IRQ+0x4b/0xd0
[  428.526456]  [<ffffffffa271a282>] common_interrupt+0x82/0x82
[  428.541125]  <EOI> [  428.544999]  [<ffffffffa2718f36>] ? native_safe_halt+0x6/0x10
[  428.559947]  [<ffffffffa2718c10>] default_idle+0x20/0x100
[  428.574182]  [<ffffffffa2038f3f>] arch_cpu_idle+0xf/0x20
[  428.588183]  [<ffffffffa27190b3>] default_idle_call+0x23/0x30
[  428.603091]  [<ffffffffa20c81b1>] cpu_startup_entry+0x1c1/0x230
[  428.618343]  [<ffffffffa270bc94>] rest_init+0x84/0x90
[  428.631830]  [<ffffffffa2d58f7d>] start_kernel+0x438/0x445
[  428.646182]  [<ffffffffa2d58120>] ? early_idt_handler_array+0x120/0x120
[  428.662761]  [<ffffffffa2d582ca>] x86_64_start_reservations+0x24/0x26
[  428.678952]  [<ffffffffa2d5840a>] x86_64_start_kernel+0x13e/0x14d
[  428.694421] Code: 00 ba 01 00 00 00 be 01 00 00 00 e8 4f 78 c0 ff 5b 5d c3 66 90 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 54 53 <48> 8b 87 e0 01 00 00 48 89 fb a8 20 75 20 48 8d bb 30 02 00 00 
[  428.740966] RIP  [<ffffffffa24bfb6c>] tty_wakeup+0xc/0x70
[  428.755113]  RSP <ffff9a1a5fc03df8>
[  428.765310] CR2: 00000000000001e0

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

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#1507292

FromMike Galbraith <umgwanakikbuti@gmail.com>
Date2016-10-24 17:20 +0200
Message-ID<svPcC-SB-15@gated-at.bofh.it>
In reply to#1507264
On Mon, 2016-10-24 at 16:48 +0200, Borislav Petkov wrote:
> Hi people,
> 
> typing "reboot" splats the following on the serial console. Ideas?

Very familiar, I bisected that to 761ed4a94582.  Workaround for the
nonce is to comment out..

	port->console = uart_console(uport);

..in drivers/tty/serial/serial_core.c::uart_add_one_port().

	-Mike

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#1507300

FromJiri Slaby <jslaby@suse.cz>
Date2016-10-24 17:30 +0200
Message-ID<svPmi-ZI-13@gated-at.bofh.it>
In reply to#1507264
On 10/24/2016, 04:48 PM, Borislav Petkov wrote:
> Hi people,
> 
> typing "reboot" splats the following on the serial console. Ideas?
> 
> INIT: Sending p[  427.863916] BUG: unable to handle kernel NULL pointer dereference at 00000000000001e0
> [  427.885156] IP: [<ffffffffa24bfb6c>] tty_wakeup+0xc/0x70
> [  427.898337] PGD 0 [  427.902051] 
> [  427.907498] Oops: 0000 [#1] PREEMPT SMP
> [  427.917635] Modules linked in: nfsv3 nfs_acl nfs fscache lockd sunrpc grace edd af_packet cpufreq_conservative cpufreq_userspace cpufreq_powersave fuse loop md_mod dm_mod joydev hid_generic usbhid ipmi_ssif ohci_pci ohci_hcd ehci_pci ehci_hcd e1000e ptp firewire_ohci edac_core pps_core tpm_infineon sp5100_tco firewire_core acpi_cpufreq serio_raw pcspkr fjes usbcore shpchp edac_mce_amd tpm_tis ipmi_si tpm_tis_core i2c_piix4 k10temp sg ipmi_msghandler tpm sr_mod button cdrom kvm_amd kvm irqbypass crc_itu_t ast ttm drm_kms_helper drm fb_sys_fops sysimgblt sysfillrect syscopyarea i2c_algo_bit scsi_dh_rdac scsi_dh_alua scsi_dh_emc scsi_dh_hp_sw ata_generic pata_atiixp
> [  428.054179] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc1-1.g73e3f23-default #1
> [  428.072868] Hardware name: System manufacturer System Product Name/KGP(M)E-D16, BIOS 0902    12/03/2010
> [  428.094755] task: ffffffffa2c0d500 task.stack: ffffffffa2c00000
> [  428.109717] RIP: 0010:[<ffffffffa24bfb6c>]  [<ffffffffa24bfb6c>] tty_wakeup+0xc/0x70
> [  428.128407] RSP: 0018:ffff9a1a5fc03df8  EFLAGS: 00010086
> [  428.142184] RAX: ffff9a1857258000 RBX: ffffffffa3050ea0 RCX: 0000000000000000
> [  428.159649] RDX: 000000000000001b RSI: 0000000000000000 RDI: 0000000000000000
> [  428.177109] RBP: ffff9a1a5fc03e08 R08: 0000000000000000 R09: 0000000000000000
> [  428.194547] R10: 0000000000021c77 R11: 0000000000000000 R12: ffff9a1857258000
> [  428.212002] R13: 0000000000000000 R14: 0000000000000020 R15: 0000000000000020
> [  428.229481] FS:  0000000000000000(0000) GS:ffff9a1a5fc00000(0000) knlGS:0000000000000000
> [  428.248938] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  428.263726] CR2: 00000000000001e0 CR3: 0000000390c06000 CR4: 00000000000006f0
> [  428.281331] Stack:
> [  428.288696]  ffffffffa3050ea0 ffff9a1857258000 ffff9a1a5fc03e18 ffffffffa24e0ab1
> [  428.307064]  ffff9a1a5fc03e40 ffffffffa24e8865 ffffffffa3050ea0 00000000000000c2
> [  428.325456]  0000000000000046 ffff9a1a5fc03e78 ffffffffa24e8a5f ffffffffa3050ea0
> [  428.343905] Call Trace:
> [  428.352319]  <IRQ> [  428.356216]  [<ffffffffa24e0ab1>] uart_write_wakeup+0x21/0x30

From the quick look, uart_write_wakeup should now be using refcounting.
Does this help (compile-tested only)?

--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -106,12 +106,17 @@ static inline struct uart_port
*uart_port_check(struct uart_state *state)
 void uart_write_wakeup(struct uart_port *port)
 {
        struct uart_state *state = port->state;
+       struct tty_struct *ttyp;
        /*
         * This means you called this function _after_ the port was
         * closed.  No cookie for you.
         */
        BUG_ON(!state);
-       tty_wakeup(state->port.tty);
+
+       ttyp = tty_port_tty_get(&state->port);
+       if (ttyp)
+               tty_wakeup(ttyp);
+       tty_kref_put(ttyp);
 }

 static void uart_stop(struct tty_struct *tty)


thanks,
-- 
js
suse labs

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#1507606

FromBorislav Petkov <bp@alien8.de>
Date2016-10-24 21:00 +0200
Message-ID<svSDx-34S-65@gated-at.bofh.it>
In reply to#1507300
On Mon, Oct 24, 2016 at 05:28:24PM +0200, Jiri Slaby wrote:
> From the quick look, uart_write_wakeup should now be using refcounting.
> Does this help (compile-tested only)?

Yes, it does. Thanks!

Reported-and-tested-by: Borislav Petkov <bp@suse.de>

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

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#1507917

FromMike Galbraith <mgalbraith@suse.de>
Date2016-10-25 03:50 +0200
Message-ID<svZ2h-7cG-11@gated-at.bofh.it>
In reply to#1507300
On Mon, 2016-10-24 at 17:28 +0200, Jiri Slaby wrote:
On 10/24/2016, 04:48 PM, Borislav Petkov wrote:
> Hi people,
> 
> typing "reboot" splats the following on the serial console. Ideas?
> 
> INIT: Sending p[  427.863916] BUG: unable to handle kernel NULL pointer dereference at 00000000000001e0
> [  427.885156] IP: [] tty_wakeup+0xc/0x70
> [  427.898337] PGD 0 [  427.902051] 
> [  427.907498] Oops: 0000 [#1] PREEMPT SMP
> [  427.917635] Modules linked in: nfsv3 nfs_acl nfs fscache lockd sunrpc grace edd af_packet cpufreq_conservative cpufreq_userspace cpufreq_powersave fuse loop md_mod dm_mod joydev hid_generic usbhid ipmi_ssif ohci_pci ohci_hcd ehci_pci ehci_hcd e1000e ptp firewire_ohci edac_core pps_core tpm_infineon sp5100_tco firewire_core acpi_cpufreq serio_raw pcspkr fjes usbcore shpchp edac_mce_amd tpm_tis ipmi_si tpm_tis_core i2c_piix4 k10temp sg ipmi_msghandler tpm sr_mod button cdrom kvm_amd kvm irqbypass crc_itu_t ast ttm drm_kms_helper drm fb_sys_fops sysimgblt sysfillrect syscopyarea i2c_algo_bit scsi_dh_rdac scsi_dh_alua scsi_dh_emc scsi_dh_hp_sw ata_generic pata_atiixp
> [  428.054179] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc1-1.g73e3f23-default #1
> [  428.072868] Hardware name: System manufacturer System Product Name/KGP(M)E-D16, BIOS 0902    12/03/2010
> [  428.094755] task: ffffffffa2c0d500 task.stack: ffffffffa2c00000
> [  428.109717] RIP: 0010:[]  [] tty_wakeup+0xc/0x70
> [  428.128407] RSP: 0018:ffff9a1a5fc03df8  EFLAGS: 00010086
> [  428.142184] RAX: ffff9a1857258000 RBX: ffffffffa3050ea0 RCX: 0000000000000000
> [  428.159649] RDX: 000000000000001b RSI: 0000000000000000 RDI: 0000000000000000
> [  428.177109] RBP: ffff9a1a5fc03e08 R08: 0000000000000000 R09: 0000000000000000
> [  428.194547] R10: 0000000000021c77 R11: 0000000000000000 R12: ffff9a1857258000
> [  428.212002] R13: 0000000000000000 R14: 0000000000000020 R15: 0000000000000020
> [  428.229481] FS:  0000000000000000(0000) GS:ffff9a1a5fc00000(0000) knlGS:0000000000000000
> [  428.248938] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  428.263726] CR2: 00000000000001e0 CR3: 0000000390c06000 CR4: 00000000000006f0
> [  428.281331] Stack:
> [  428.288696]  ffffffffa3050ea0 ffff9a1857258000 ffff9a1a5fc03e18 ffffffffa24e0ab1
> [  428.307064]  ffff9a1a5fc03e40 ffffffffa24e8865 ffffffffa3050ea0 00000000000000c2
> [  428.325456]  0000000000000046 ffff9a1a5fc03e78 ffffffffa24e8a5f ffffffffa3050ea0
> [  428.343905] Call Trace:
> [  428.352319]   [  428.356216]  [] uart_write_wakeup+0x21/0x30
> Does this help (compile-tested only)?
> 
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -106,12 +106,17 @@ static inline struct uart_port
> *uart_port_check(struct uart_state *state)
>  void uart_write_wakeup(struct uart_port *port)
>  {
>         struct uart_state *state = port->state;
> +       struct tty_struct *ttyp;
>         /*
>          * This means you called this function _after_ the port was
>          * closed.  No cookie for you.
>          */
>         BUG_ON(!state);
> -       tty_wakeup(state->port.tty);
> +
> +       ttyp = tty_port_tty_get(&state->port);
> +       if (ttyp)
> +               tty_wakeup(ttyp);
> +       tty_kref_put(ttyp);
>  }
> 
>  static void uart_stop(struct tty_struct *tty)

Well, I now see that Boris has already tested it, but since I just did
that too, I'll add a CC to make my 'yup, all better' less redundant :)

	-Mike

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