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/linux-usb@xxxxxxxxxxxxxxx/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 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
