Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: WARNING: ODEBUG bug in tcindex_destroy_work (3) | Date | Sat, 21 Mar 2020 11:19:20 +0100 |
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syzbot <syzbot+46f513c3033d592409d2@syzkaller.appspotmail.com> writes: > syzbot has found a reproducer for the following crash on: > > HEAD commit: 74522e7b net: sched: set the hw_stats_type in pedit loop > git tree: net-next > console output: https://syzkaller.appspot.com/x/log.txt?x=14c85173e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=b5acf5ac38a50651 > dashboard link: https://syzkaller.appspot.com/bug?extid=46f513c3033d592409d2 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17bfff65e00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+46f513c3033d592409d2@syzkaller.appspotmail.com > > ------------[ cut here ]------------ > ODEBUG: free active (active state 0) object type: work_struct hint: tcindex_destroy_rexts_work+0x0/0x20 net/sched/cls_tcindex.c:143 ... > __debug_check_no_obj_freed lib/debugobjects.c:967 [inline] > debug_check_no_obj_freed+0x2e1/0x445 lib/debugobjects.c:998 > kfree+0xf6/0x2b0 mm/slab.c:3756 > tcindex_destroy_work+0x2e/0x70 net/sched/cls_tcindex.c:231
So this is:
kfree(p->perfect);
Looking at the place which queues that work:
tcindex_destroy()
if (p->perfect) { if (tcf_exts_get_net(&r->exts)) tcf_queue_work(&r-rwork, tcindex_destroy_rexts_work); else __tcindex_destroy_rexts(r) }
..... tcf_queue_work(&p->rwork, tcindex_destroy_work); So obviously if tcindex_destroy_work() runs before tcindex_destroy_rexts_work() then the above happens.
Thanks,
tglx
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