Messages in this thread | | | Date | Wed, 27 Oct 2021 19:03:58 +0200 | Subject | Re: [syzbot] KASAN: slab-out-of-bounds Read in copy_data | From | Laurent Vivier <> |
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On 27/10/2021 18:25, Laurent Vivier wrote: > On 27/10/2021 17:28, Michael S. Tsirkin wrote: >> On Wed, Oct 27, 2021 at 03:36:19PM +0200, Dmitry Vyukov wrote: >>> On Wed, 27 Oct 2021 at 15:11, Laurent Vivier <lvivier@redhat.com> wrote: >>>> >>>> On 26/10/2021 18:39, syzbot wrote: >>>>> Hello, >>>>> >>>>> syzbot found the following issue on: >>>>> >>>>> HEAD commit: 9ae1fbdeabd3 Add linux-next specific files for 20211025 >>>>> git tree: linux-next >>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=1331363cb00000 >>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=aeb17e42bc109064 >>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=b86736b5935e0d25b446 >>>>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for >>>>> Debian) 2.35.2 >>>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=116ce954b00000 >>>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132fcf62b00000 >>>>> >>>>> The issue was bisected to: >>>>> >>>>> commit 22849b5ea5952d853547cc5e0651f34a246b2a4f >>>>> Author: Leon Romanovsky <leonro@nvidia.com> >>>>> Date: Thu Oct 21 14:16:14 2021 +0000 >>>>> >>>>> devlink: Remove not-executed trap policer notifications >>>>> >>>>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=137d8bfcb00000 >>>>> final oops: https://syzkaller.appspot.com/x/report.txt?x=10fd8bfcb00000 >>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=177d8bfcb00000 >>>>> >>>>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>>>> Reported-by: syzbot+b86736b5935e0d25b446@syzkaller.appspotmail.com >>>>> Fixes: 22849b5ea595 ("devlink: Remove not-executed trap policer notifications") >>>>> >>>>> ================================================================== >>>>> BUG: KASAN: slab-out-of-bounds in memcpy include/linux/fortify-string.h:225 [inline] >>>>> BUG: KASAN: slab-out-of-bounds in copy_data+0xf3/0x2e0 >>>>> drivers/char/hw_random/virtio-rng.c:68 >>>>> Read of size 64 at addr ffff88801a7a1580 by task syz-executor989/6542 >>>>> >>>> >>>> I'm not able to reproduce the problem with next-20211026 and the C reproducer. >>>> >>>> And reviewing the code in copy_data() I don't see any issue. >>>> >>>> Is it possible to know what it the VM configuration used to test it? >>> >>> Hi Laurent, >>> >>> syzbot used e2-standard-2 GCE VM when that happened. >>> You can see some info about these VMs under the "VM info" link on the dashboard. >> >> Could you pls confirm whether reverting >> caaf2874ba27b92bca6f0298bf88bad94067ec37 addresses this? >> > > I've restarted the syzbot on top of "hwrng: virtio - don't wait on cleanup" [1] and the > problem has not been triggered. > > See https://syzkaller.appspot.com/bug?extid=b86736b5935e0d25b446
The problem seems to be introduced by the last patch:
"hwrng: virtio - always add a pending request"
not
"hwrng: virtio - don't waste entropy"
Thanks, Laurent
> > Thanks, > Laurent > > [1] > d721abbeb145 hwrng: virtio - don't wait on cleanup > bb768beb0a5f hwrng: virtio - add an internal buffer > d25f27432f80 (origin/master, origin/HEAD, master) Merge tag 'arm-soc-fixes-5.15-3' of > git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc >
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