On Sat, 2011-11-12 at 11:15 +0530, Krishna Kumar wrote: > Sasha Levin <levinsasha928@xxxxxxxxx> wrote on 11/12/2011 03:32:04 AM: > > > I'm seeing this BUG() sometimes when running it using a small patch I > > did for KVM tool: > > > > [ 1.281531] Call Trace: > > [ 1.281531] [<ffffffff8138a0e5>] ? free_rq_sq+0x2c/0xce > > [ 1.281531] [<ffffffff8138bb63>] ? virtnet_probe+0x81c/0x855 > > [ 1.281531] [<ffffffff8129c9e7>] ? virtio_dev_probe+0xa7/0xc6 > > [ 1.281531] [<ffffffff8134d2c3>] ? driver_probe_device+0xb2/0x142 > > [ 1.281531] [<ffffffff8134d3a2>] ? __driver_attach+0x4f/0x6f > > [ 1.281531] [<ffffffff8134d353>] ? driver_probe_device+0x142/0x142 > > [ 1.281531] [<ffffffff8134c3ab>] ? bus_for_each_dev+0x47/0x72 > > [ 1.281531] [<ffffffff8134c90d>] ? bus_add_driver+0xa2/0x1e6 > > [ 1.281531] [<ffffffff81cc1b36>] ? tun_init+0x89/0x89 > > [ 1.281531] [<ffffffff8134db59>] ? driver_register+0x8d/0xf8 > > [ 1.281531] [<ffffffff81cc1b36>] ? tun_init+0x89/0x89 > > [ 1.281531] [<ffffffff81c98ac1>] ? do_one_initcall+0x78/0x130 > > [ 1.281531] [<ffffffff81c98c0e>] ? kernel_init+0x95/0x113 > > [ 1.281531] [<ffffffff81658274>] ? kernel_thread_helper+0x4/0x10 > > [ 1.281531] [<ffffffff81c98b79>] ? do_one_initcall+0x130/0x130 > > [ 1.281531] [<ffffffff81658270>] ? gs_change+0x13/0x13 > > [ 1.281531] Code: c2 85 d2 48 0f 45 2d d1 39 ce 00 eb 22 65 8b 14 25 > > 90 cc 00 00 48 8b 05 f0 a6 bc 00 48 63 d2 4c 89 e7 48 03 3c d0 e8 83 dd > > 00 00 > > [ 1.281531] 8b 68 10 44 89 e6 48 89 ef 2b 75 18 e8 e4 f1 ff ff 8b 05 > > fd > > [ 1.281531] RIP [<ffffffff810b3ac7>] free_percpu+0x9a/0x104 > > [ 1.281531] RSP <ffff88001383fd50> > > [ 1.281531] CR2: 0000000000000010 > > [ 1.281531] ---[ end trace 68cbc23dfe2fe62a ]--- > > > > I don't have time today to dig into it, sorry. > > Thanks for the report. > > free_rq_sq() was being called twice in the failure path. The second > call panic'd since it had freed the same pointers earlier. > > 1. free_rq_sq() was being called twice in the failure path. > virtnet_setup_vqs() had already freed up rq/sq on error, and > virtnet_probe() tried to do it again. Fix it in virtnet_probe > by moving the call up. > 2. Make free_rq_sq() re-entrant by setting freed pointers to NULL. > 3. Remove free_stats() as it was being called only once. > > Sasha, could you please try this patch on top of existing patches? > > thanks! > > Signed-off-by: krkumar2@xxxxxxxxxx > --- [snip] I've tested it and it looks good, no BUG() or panic. I would suggest adding some output if we take the failure path, since while the guest does boot peacefully, it doesn't have a network interface and there's nothing in the boot log to indicate anything has gone wrong. -- Sasha. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
