Re: might_sleep in aic79xx scsi driver code of 2.6.5

[Luben Tuikov <luben_tuikov@adaptec.com>]

Hi Masao,

Thanks you for pointing this out.  I'm seeing a similar
failure (mine says: "bad: scheduling while atomic") on
head of line scsi-misc-2.6 when I rmmod aic79xx.

I'll investigate both failures.

Thanks,
	Luben


Masao Fukuchi wrote:
> Hello,
> 
> My colleague sent following mail to Linux Kernel Mailing List. 
> But there was no response to this mail.
> So, I forward the mail to Linux SCSI Mailing List.
> The problem is PHP operation(remove) failure(Adaptec 39320D).
> 
> I think the cause of this problem is aix79xx driver sleeps with 
> spin_lock_irqsave().
> 
> Please look at following mail.
> 
> Thanks,
> M.Fukuchi
> 
> NIWA Hideyuki wrote:
> Hello,
> 
>    I tried to hot-remove a PCI scsi card (Adaptec 39320D: aic79xx).
>    And, the following kernel messages were output.
> 
>    Because aic79xx driver called semaphore with lock environment.
>    It was detected in __might_sleep() check .
>                                                                                 
>         Kernel is 2.6.5. 
>         CPU is ia64(itanium2 4way), memory is 2GB. 
>         And my server have hotpluggable PCI-slots.
> 
> kernel messages: 
>                                                                                
> kernel: Debug: sleeping function called from invalid context at 
> include/asm/semaphore.h:76
> kernel: in_atomic():0, irqs_disabled():1
> kernel: 
> kernel: Call Trace:
> kernel:  [<a000000100018dc0>] show_stack+0x80/0xa0
> kernel:                     sp=e0000004fff17b70 bsp=e0000004fff11298
> kernel:  [<a0000001000678a0>] __might_sleep+0x1a0/0x1c0
> kernel:                     sp=e0000004fff17d40 bsp=e0000004fff11270
> kernel:  [<a0000002007d1bf0>] ahd_linux_kill_dv_thread+0x170/0x280 [aic79xx]
>                               ~~~~~~~~~~~~~~~~~~~~~~~~
> kernel:                     sp=e0000004fff17d50 bsp=e0000004fff11248
> kernel:  [<a0000002007d03e0>] ahd_platform_free+0x80/0x3e0 [aic79xx]
> kernel:                     sp=e0000004fff17d50 bsp=e0000004fff111f0
> kernel:  [<a00000020079d3f0>] ahd_free+0x1f0/0x3e0 [aic79xx]
>                               ~~~~~~~~
> kernel:                     sp=e0000004fff17d50 bsp=e0000004fff111c0
> kernel:  [<a0000002007dc7f0>] ahd_linux_pci_dev_remove+0x1b0/0x220 [aic79xx]
> kernel:                     sp=e0000004fff17d50 bsp=e0000004fff11188
> kernel:  [<a000000100201720>] pci_device_remove+0xc0/0xe0
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff11160
> kernel:  [<a0000001002ba900>] device_release_driver+0x120/0x140
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff11130
> kernel:  [<a0000001002bac60>] bus_remove_device+0xe0/0x1e0
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff11100
> kernel:  [<a0000001002b7af0>] device_del+0x150/0x240
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff110c0
> kernel:  [<a0000001002b7c00>] device_unregister+0x20/0x60
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff110a0
> kernel:  [<a0000001001fd2f0>] pci_destroy_dev+0x30/0x160
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff11080
> kernel:  [<a000000200383d30>] acpiphp_unconfigure_function+0x70/0x160 [acpiphp]
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff11050
> kernel:  [<a000000200381410>] disable_device+0x130/0x140 [acpiphp]
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff11020
> kernel:  [<a000000200382180>] acpiphp_disable_slot+0x80/0x280 [acpiphp]
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff10fe8
> kernel:  [<a000000200381ae0>] handle_hotplug_event_func+0x120/0x320 [acpiphp]
> kernel:                     sp=e0000004fff17d60 bsp=e0000004fff10fb8
> kernel:  [<a00000010021ca80>] acpi_ev_notify_dispatch+0x140/0x180
> kernel:                     sp=e0000004fff17db0 bsp=e0000004fff10f98
> kernel:  [<a000000100211010>] acpi_os_execute_deferred+0x50/0x80
> kernel:                     sp=e0000004fff17db0 bsp=e0000004fff10f78
> kernel:  [<a000000100095180>] worker_thread+0x420/0x5c0
> kernel:                     sp=e0000004fff17db0 bsp=e0000004fff10ee0
> kernel:  [<a00000010009eaa0>] kthread+0x160/0x180
> kernel:                     sp=e0000004fff17e20 bsp=e0000004fff10ea8
> kernel:  [<a00000010001a9b0>] kernel_thread_helper+0x30/0x60
> kernel:                     sp=e0000004fff17e30 bsp=e0000004fff10e80
> kernel:  [<a000000100008c40>] start_kernel_thread+0x20/0x40
> kernel:                     sp=e0000004fff17e30 bsp=e0000004fff10e80
> kernel: Synchronizing SCSI cache for disk sdd: <4>FAILED
> kernel:   status = 0, message = 00, host = 1, driver = 00
> 
> 
> __might_sleep() function called from lock context.
> That has been detected at down() in ahd_linux_kill_dv_thread(). 
> (drivers/scsi/aic7xxx/aic79xx_osm.c)
> 
> 
>>static void
>>ahd_linux_kill_dv_thread(struct ahd_softc *ahd)
>>{
>>        u_long s;
> 
> 
>         ...
> 
> 
>>                 * parent (dv threads are parented by init).
>>                 * Cross your fingers...
>>                 */
>>                down(&ahd->platform_data->eh_sem); <<<<< called __might_sleep
>>
> 
>  
> 
> 
> ahd_list_lock() have locked in ahd_linux_pci_dev_remove() .
> (drivers/scsi/aic7xxx/aic79xx_osm_pci.c)
> 
> 
>>static void
>>ahd_linux_pci_dev_remove(struct pci_dev *pdev)
>>{
>>        struct ahd_softc *ahd;
>>        u_long l;
>>
>>        /*
>>         * We should be able to just perform
>>         * the free directly, but check our
>>         * list for extra sanity.
>>         */
>>        ahd_list_lock(&l); <<<<< lock: called spin_lock_irqsave() 
>>        ahd = ahd_find_softc((struct ahd_softc *)pci_get_drvdata(pdev));
>>        if (ahd != NULL) {
>>                u_long s;
>>
>>                ahd_lock(ahd, &s);
>>                ahd_intr_enable(ahd, FALSE);
>>                ahd_unlock(ahd, &s);
>>                ahd_free(ahd);  <<<<< called ahd_platform_free =>
> 
>                                              called ahd_linux_kill_dv_thread  
> 
>>        }
>>        ahd_list_unlock(&l);  <<<<< unlock : 
>>}
> 
> 
> Maybe, ai7xxx driver has a same problem.
> 
> Thanks in advance
> NIWA Hideyuki