Hi,
I am not certain to to forward this to, so I am trying linux-usb and ext4. Please add relevant people/lists, thank you.
# dmesg | grep "UBSAN: Undefined behaviour"
[ 2.638843] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:873:47
[ 8.553620] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2612:15
[ 25.341048] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1274:11
[ 41.460542] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
#
Full dmesg is attached.
Hope this helps,
Martin
On Thu, Apr 21, 2016 at 12:22:49AM +0200, Martin MOKREJŠ wrote:
> Hi,
> I am not certain to to forward this to, so I am trying linux-usb and ext4. Please add relevant people/lists, thank you.
>
> # dmesg | grep "UBSAN: Undefined behaviour"
> [ 2.638843] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:873:47
> [ 8.553620] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2612:15
> [ 25.341048] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1274:11
> [ 41.460542] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
> #
>
> Full dmesg is attached.
>
> Hope this helps,
> Martin
> [ 0.000000] Linux version 4.5.1-default-pciehp (root@vostro) (gcc version 5.3.0 (Gentoo 5.3.0 p1.0, pie-0.6.5) ) #1 SMP Thu Apr 14 14:17:48 CEST 2016
Please try 4.6-rc4, a number of UBSAN issues have been fixed there.
thansk,
greg k-h
Hi Greg,
thank you for your answer.
Greg KH wrote:
> On Thu, Apr 21, 2016 at 12:22:49AM +0200, Martin MOKREJŠ wrote:
>> Hi,
>> I am not certain to to forward this to, so I am trying linux-usb and ext4. Please add relevant people/lists, thank you.
>>
>> # dmesg | grep "UBSAN: Undefined behaviour"
>> [ 2.638843] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:873:47
>> [ 8.553620] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2612:15
>> [ 25.341048] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1274:11
>> [ 41.460542] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
>> #
>>
>> Full dmesg is attached.
>>
>> Hope this helps,
>> Martin
>
>> [ 0.000000] Linux version 4.5.1-default-pciehp (root@vostro) (gcc version 5.3.0 (Gentoo 5.3.0 p1.0, pie-0.6.5) ) #1 SMP Thu Apr 14 14:17:48 CEST 2016
>
> Please try 4.6-rc4, a number of UBSAN issues have been fixed there.
They are still present:
# dmesg | grep "UBSAN: Undefined behaviour"
[ 3.113405] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:877:47
[ 5.678949] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2619:15
[ 18.345599] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1281:11
[ 34.544363] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
#
Updated dmesg is attached.
Martin
On Thu, Apr 21, 2016 at 11:18:16AM +0200, Martin MOKREJŠ wrote:
> Hi Greg,
>
> thank you for your answer.
>
> Greg KH wrote:
> > On Thu, Apr 21, 2016 at 12:22:49AM +0200, Martin MOKREJŠ wrote:
> > > Hi,
> > > I am not certain to to forward this to, so I am trying linux-usb and ext4. Please add relevant people/lists, thank you.
> > >
> > > # dmesg | grep "UBSAN: Undefined behaviour"
> > > [ 2.638843] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:873:47
> > > [ 8.553620] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2612:15
> > > [ 25.341048] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1274:11
> > > [ 41.460542] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
> > > #
> > >
> > > Full dmesg is attached.
> > >
> > > Hope this helps,
> > > Martin
> >
> > > [ 0.000000] Linux version 4.5.1-default-pciehp (root@vostro) (gcc version 5.3.0 (Gentoo 5.3.0 p1.0, pie-0.6.5) ) #1 SMP Thu Apr 14 14:17:48 CEST 2016
> >
> > Please try 4.6-rc4, a number of UBSAN issues have been fixed there.
>
> They are still present:
>
> # dmesg | grep "UBSAN: Undefined behaviour"
> [ 3.113405] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:877:47
> [ 5.678949] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2619:15
> [ 18.345599] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1281:11
> [ 34.544363] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
Ah, sorry about that, turns out this is a bug in the tool, not in the
code, see the thread from a few weeks ago in the linux-usb archives with
the subject:
Subject: function ehci_hub_control in ehci-hub.c
for all of the details.
thanks,
greg k-h
Greg KH wrote:
> On Thu, Apr 21, 2016 at 11:18:16AM +0200, Martin MOKREJŠ wrote:
>> Hi Greg,
>>
>> thank you for your answer.
>>
>> Greg KH wrote:
>>> On Thu, Apr 21, 2016 at 12:22:49AM +0200, Martin MOKREJŠ wrote:
>>>> Hi,
>>>> I am not certain to to forward this to, so I am trying linux-usb and ext4. Please add relevant people/lists, thank you.
>>>>
>>>> # dmesg | grep "UBSAN: Undefined behaviour"
>>>> [ 2.638843] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:873:47
>>>> [ 8.553620] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2612:15
>>>> [ 25.341048] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1274:11
>>>> [ 41.460542] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
>>>> #
>>>>
>>>> Full dmesg is attached.
>>>>
>>>> Hope this helps,
>>>> Martin
>>>
>>>> [ 0.000000] Linux version 4.5.1-default-pciehp (root@vostro) (gcc version 5.3.0 (Gentoo 5.3.0 p1.0, pie-0.6.5) ) #1 SMP Thu Apr 14 14:17:48 CEST 2016
>>>
>>> Please try 4.6-rc4, a number of UBSAN issues have been fixed there.
>>
>> They are still present:
>>
>> # dmesg | grep "UBSAN: Undefined behaviour"
>> [ 3.113405] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:877:47
>> [ 5.678949] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2619:15
>> [ 18.345599] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1281:11
>> [ 34.544363] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
>
> Ah, sorry about that, turns out this is a bug in the tool, not in the
> code, see the thread from a few weeks ago in the linux-usb archives with
> the subject:
> Subject: function ehci_hub_control in ehci-hub.c
> for all of the details.
Thank you. I am not a programmer so I only infer from this thread I should disable
the UBSAN in .config. The kernel code is technically correct but triggers false alarm.
Maybe the UBSAN could have a whitelist of falsely matching locations?
https://www.mail-archive.com/[email protected]/msg72438.html
Did anybody check the ext4 code or is it also just believed the UBSAN complaint is
just broken and code changes are not necessary?
Martin
On Thu, Apr 21, 2016 at 01:17:19PM +0200, Martin MOKREJŠ wrote:
> Greg KH wrote:
> > On Thu, Apr 21, 2016 at 11:18:16AM +0200, Martin MOKREJŠ wrote:
> > > Hi Greg,
> > >
> > > thank you for your answer.
> > >
> > > Greg KH wrote:
> > > > On Thu, Apr 21, 2016 at 12:22:49AM +0200, Martin MOKREJŠ wrote:
> > > > > Hi,
> > > > > I am not certain to to forward this to, so I am trying linux-usb and ext4. Please add relevant people/lists, thank you.
> > > > >
> > > > > # dmesg | grep "UBSAN: Undefined behaviour"
> > > > > [ 2.638843] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:873:47
> > > > > [ 8.553620] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2612:15
> > > > > [ 25.341048] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1274:11
> > > > > [ 41.460542] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
> > > > > #
> > > > >
> > > > > Full dmesg is attached.
> > > > >
> > > > > Hope this helps,
> > > > > Martin
> > > >
> > > > > [ 0.000000] Linux version 4.5.1-default-pciehp (root@vostro) (gcc version 5.3.0 (Gentoo 5.3.0 p1.0, pie-0.6.5) ) #1 SMP Thu Apr 14 14:17:48 CEST 2016
> > > >
> > > > Please try 4.6-rc4, a number of UBSAN issues have been fixed there.
> > >
> > > They are still present:
> > >
> > > # dmesg | grep "UBSAN: Undefined behaviour"
> > > [ 3.113405] UBSAN: Undefined behaviour in drivers/usb/host/ehci-hub.c:877:47
> > > [ 5.678949] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2619:15
> > > [ 18.345599] UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1281:11
> > > [ 34.544363] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:9
> >
> > Ah, sorry about that, turns out this is a bug in the tool, not in the
> > code, see the thread from a few weeks ago in the linux-usb archives with
> > the subject:
> > Subject: function ehci_hub_control in ehci-hub.c
> > for all of the details.
>
> Thank you. I am not a programmer so I only infer from this thread I should disable
> the UBSAN in .config. The kernel code is technically correct but triggers false alarm.
> Maybe the UBSAN could have a whitelist of falsely matching locations?
>
> https://www.mail-archive.com/[email protected]/msg72438.html
It probably should be fixed to not report false things like this.
> Did anybody check the ext4 code or is it also just believed the UBSAN complaint is
> just broken and code changes are not necessary?
I'm not an ext4 developer, I'll leave that to them :)
thanks,
greg k-h