On 10/2/23 10:43 AM, Jens Axboe wrote: > On 10/2/23 8:38 AM, syzbot wrote: >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: ec8c298121e3 Merge tag 'x86-urgent-2023-10-01' of git://gi.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=16ef0ed6680000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=3be743fa9361d5b0 >> dashboard link: https://syzkaller.appspot.com/bug?extid=2113e61b8848fa7951d8 >> compiler: arm-linux-gnueabi-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 >> userspace arch: arm > > I tried the syz repro in the console output, but can't trigger it. It > also makes very little sense to me... For when there is a reproducer, > the below would perhaps shed some light on it. We have bl->is_mapped == > 1, yet bl->buf_ring is NULL. Probably some artifact of 32-bit arm? I think this is 32-bit and highmem... The page being mapped into the kernel is a highmem page, and this won't really fly with having a permanent ->buf_ring address which we get from page_address(). -- Jens Axboe
