On Mon, Nov 2, 2020 at 12:54 PM syzbot <syzbot+d29e58bb557324e55e5e@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 080b6f40 bpf: Don't rely on GCC __attribute__((optimize)) .. > git tree: bpf > console output: https://syzkaller.appspot.com/x/log.txt?x=1089d37c500000 > kernel config: https://syzkaller.appspot.com/x/.config?x=58a4ca757d776bfe > dashboard link: https://syzkaller.appspot.com/bug?extid=d29e58bb557324e55e5e > compiler: gcc (GCC) 10.1.0-syz 20200507 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10f4b032500000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1371a47c500000 > > The issue was bisected to: > > commit 9df1c28bb75217b244257152ab7d788bb2a386d0 > Author: Matt Mullins <mmullins@xxxxxx> > Date: Fri Apr 26 18:49:47 2019 +0000 > > bpf: add writable context for raw tracepoints We have a number of kernel memory corruptions related to bpf_trace_run now: https://groups.google.com/g/syzkaller-bugs/search?q=kernel%2Ftrace%2Fbpf_trace.c Can raw tracepoints "legally" corrupt kernel memory (a-la /dev/kmem)? Or they shouldn't? Looking at the description of Matt's commit, it seems that corruptions should not be possible (bounded buffer, checked size, etc). Then it means it's a real kernel bug? > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12b6c4da500000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=11b6c4da500000 > console output: https://syzkaller.appspot.com/x/log.txt?x=16b6c4da500000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+d29e58bb557324e55e5e@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 9df1c28bb752 ("bpf: add writable context for raw tracepoints") > > ================================================================== > BUG: KASAN: vmalloc-out-of-bounds in __bpf_trace_run kernel/trace/bpf_trace.c:2045 [inline] > BUG: KASAN: vmalloc-out-of-bounds in bpf_trace_run3+0x3e0/0x3f0 kernel/trace/bpf_trace.c:2083 > Read of size 8 at addr ffffc90000e6c030 by task kworker/0:3/3754 > > CPU: 0 PID: 3754 Comm: kworker/0:3 Not tainted 5.9.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Workqueue: 0x0 (events) > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x107/0x163 lib/dump_stack.c:118 > print_address_description.constprop.0.cold+0x5/0x4c8 mm/kasan/report.c:385 > __kasan_report mm/kasan/report.c:545 [inline] > kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 > __bpf_trace_run kernel/trace/bpf_trace.c:2045 [inline] > bpf_trace_run3+0x3e0/0x3f0 kernel/trace/bpf_trace.c:2083 > __bpf_trace_sched_switch+0xdc/0x120 include/trace/events/sched.h:138 > __traceiter_sched_switch+0x64/0xb0 include/trace/events/sched.h:138 > trace_sched_switch include/trace/events/sched.h:138 [inline] > __schedule+0xeb8/0x2130 kernel/sched/core.c:4520 > schedule+0xcf/0x270 kernel/sched/core.c:4601 > worker_thread+0x14c/0x1120 kernel/workqueue.c:2439 > kthread+0x3af/0x4a0 kernel/kthread.c:292 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 > > > Memory state around the buggy address: > ffffc90000e6bf00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > ffffc90000e6bf80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > >ffffc90000e6c000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > ^ > ffffc90000e6c080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 > ffffc90000e6c100: 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. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/00000000000004500b05b31e68ce%40google.com.
