On Mon, Feb 14, 2022 at 3:52 PM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > > Song, ptal. > > On 2/14/22 7:45 PM, syzbot wrote: > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: e5313968c41b Merge branch 'Split bpf_sk_lookup remote_port.. > > git tree: bpf-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=10baced8700000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=c40b67275bfe2a58 > > dashboard link: https://syzkaller.appspot.com/bug?extid=2f649ec6d2eea1495a8f > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > > > Unfortunately, I don't have any reproducer for this issue yet. > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+2f649ec6d2eea1495a8f@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > ================================================================== > > BUG: KASAN: vmalloc-out-of-bounds in bpf_jit_binary_pack_free kernel/bpf/core.c:1120 [inline] > > BUG: KASAN: vmalloc-out-of-bounds in bpf_jit_free+0x2b5/0x2e0 kernel/bpf/core.c:1151 > > Read of size 4 at addr ffffffffa0001a80 by task kworker/0:18/13642 > > > > CPU: 0 PID: 13642 Comm: kworker/0:18 Not tainted 5.16.0-syzkaller-11655-ge5313968c41b #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > Workqueue: events bpf_prog_free_deferred > > Call Trace: > > <TASK> > > __dump_stack lib/dump_stack.c:88 [inline] > > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 > > print_address_description.constprop.0.cold+0xf/0x336 mm/kasan/report.c:255 > > __kasan_report mm/kasan/report.c:442 [inline] > > kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 > > bpf_jit_binary_pack_free kernel/bpf/core.c:1120 [inline] > > bpf_jit_free+0x2b5/0x2e0 kernel/bpf/core.c:1151 > > bpf_prog_free_deferred+0x5c1/0x790 kernel/bpf/core.c:2524 > > process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 > > worker_thread+0x657/0x1110 kernel/workqueue.c:2454 > > kthread+0x2e9/0x3a0 kernel/kthread.c:377 > > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 > > </TASK> I think this is the same issue as [1], that the 2MB page somehow got freed while still in use. I couldn't spot any bug with bpf_prog_pack allocate/free logic. I haven't got luck reproducing it either. Will continue tomorrow. [1] https://lore.kernel.org/netdev/0000000000007646bd05d7f81943@xxxxxxxxxx/t/ > > > > > > Memory state around the buggy address: > > ffffffffa0001980: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > > ffffffffa0001a00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > >> ffffffffa0001a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > > ^ > > ffffffffa0001b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > > ffffffffa0001b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > > ================================================================== > > > > > > --- > > This report is generated by a bot. It may contain errors. > > See https://goo.gl/tpsmEJ for more information about syzbot. > > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > > > syzbot will keep track of this issue. See: > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > >
