On Mon, 11 Jan 2021 at 10:16, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > On Sun, Jan 10, 2021 at 10:34 PM syzbot > <syzbot+5f326d255ca648131f87@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > syzbot suspects this issue was fixed by commit: > > > > commit 537cf4e3cc2f6cc9088dcd6162de573f603adc29 > > Author: Magnus Karlsson <magnus.karlsson@xxxxxxxxx> > > Date: Fri Nov 20 11:53:39 2020 +0000 > > > > xsk: Fix umem cleanup bug at socket destruct > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=139f3dfb500000 > > start commit: e87d24fc Merge branch 'net-iucv-fixes-2020-11-09' > > git tree: net > > kernel config: https://syzkaller.appspot.com/x/.config?x=61033507391c77ff > > dashboard link: https://syzkaller.appspot.com/bug?extid=5f326d255ca648131f87 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10d10006500000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=126c9eaa500000 > > > > If the result looks correct, please mark the issue as fixed by replying with: > > > > #syz fix: xsk: Fix umem cleanup bug at socket destruct > > > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > FTR, the bisection log looks clean, but this does not look like the > fix for this. The reproducer does not destroy sockets. I think it's the correct fix. The crash report also has this, which shows the reproducer does actually destroy sockets: xdp_umem_addr_unmap net/xdp/xdp_umem.c:44 [inline] xdp_umem_release net/xdp/xdp_umem.c:62 [inline] xdp_put_umem+0x113/0x330 net/xdp/xdp_umem.c:80 xsk_destruct net/xdp/xsk.c:1150 [inline] xsk_destruct+0xc0/0xf0 net/xdp/xsk.c:1142 __sk_destruct+0x4b/0x8f0 net/core/sock.c:1759 rcu_do_batch kernel/rcu/tree.c:2476 [inline] I've tested the reproducer on both 537cf4e3cc2f and 537cf4e3cc2f^ and it only reproduces on 537cf4e3cc2f^ here (with the same stack trace as the syzbot report). The repro I used was https://syzkaller.appspot.com/text?tag=ReproSyz&x=10d10006500000 which is just: r0 = socket$xdp(0x2c, 0x3, 0x0) setsockopt$XDP_UMEM_REG(r0, 0x11b, 0x4, &(0x7f0000000040)={&(0x7f0000000000)=""/2, 0x1000000, 0x1000}, 0x20) so the socket definitely gets created/destroyed. Feel free to undo if you disagree: #syz fix: xsk: Fix umem cleanup bug at socket destruct Vegard
