> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Monday, September 18, 2017 5:55 AM > To: KY Srinivasan <kys@xxxxxxxxxxxxx> > Cc: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>; > leann.ogasawara@xxxxxxxxxxxxx; Stephen Hemminger > <sthemmin@xxxxxxxxxxxxx>; apw@xxxxxxxxxxxxx; olaf@xxxxxxxxx; > marcelo.cerri@xxxxxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; Haiyang Zhang > <haiyangz@xxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; > jasowang@xxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH 1/1] Drivers: hv: vmbus: Fix rescind handling issues > > Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> writes: > > > > > Reverting 6f3d791f300618caf82a2be0c27456edd76d5164 still helps. > > In addition to the above I got the following crash while playing with > 4.14-rc1 (unmodified): > > [ 55.810080] kernel tried to execute NX-protected page - exploit attempt? > (uid: 0) > [ 55.814293] BUG: unable to handle kernel paging request at > ffff8800059985f0 > [ 55.818065] IP: 0xffff8800059985f0 > [ 55.819925] PGD 22eb067 P4D 22eb067 PUD 22ec067 PMD 5f37063 PTE > 8000000005998163 > [ 55.820018] Oops: 0011 [#1] SMP > [ 55.820018] Modules linked in: vfat fat bnx2x mdio efi_pstore hv_utils > efivars pci_hyperv ptp pps_core pcspkr hv_balloon xfs libcrc32c hv_storvsc > hyperv_fb hv_netvsc scsi_transport_fc hid_hyperv hyperv_keyboard > hv_vmbus > [ 55.834837] CPU: 0 PID: 498 Comm: kworker/0:2 Not tainted 4.14.0-rc1 #63 > [ 55.834837] Hardware name: Microsoft Corporation Virtual Machine/Virtual > Machine, BIOS Hyper-V UEFI Release v1.0 11/26/2012 > [ 55.834837] Workqueue: events vmbus_onmessage_work [hv_vmbus] > [ 55.834837] task: ffff88003f448000 task.stack: ffffc90005398000 > [ 55.834837] RIP: 0010:0xffff8800059985f0 > [ 55.834837] RSP: 0018:ffffc9000539be00 EFLAGS: 00010286 > [ 55.834837] RAX: ffff880005998010 RBX: ffff880005998000 RCX: > 0000000000000000 > [ 55.834837] RDX: ffff8800059985f0 RSI: 0000000000000246 RDI: > ffff880005998000 > [ 55.860040] RBP: ffffc9000539be18 R08: 00000000000002e6 R09: > 0000000000000000 > [ 55.865057] R10: ffffc9000539bdf0 R11: 000000000000a000 R12: > 0000000000000286 > [ 55.865057] R13: ffff88007ae1ed00 R14: 0000000000000000 R15: > ffff8800065c3200 > [ 55.865057] FS: 0000000000000000(0000) GS:ffff88007ae00000(0000) > knlGS:0000000000000000 > [ 55.865057] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 55.865057] CR2: ffff8800059985f0 CR3: 00000000075a5000 CR4: > 00000000001406f0 > [ 55.886745] Call Trace: > [ 55.886745] ? vmbus_onoffer_rescind+0xfa/0x160 [hv_vmbus] > [ 55.890968] vmbus_onmessage+0x2a/0x90 [hv_vmbus] > [ 55.891934] vmbus_onmessage_work+0x1d/0x30 [hv_vmbus] > [ 55.891934] process_one_work+0x193/0x390 > [ 55.891934] worker_thread+0x48/0x3c0 > [ 55.891934] kthread+0x120/0x140 > [ 55.891934] ? process_one_work+0x390/0x390 > [ 55.891934] ? kthread_create_on_node+0x60/0x60 > [ 55.891934] ret_from_fork+0x25/0x30 > [ 55.891934] Code: 88 ff ff c0 85 99 05 00 88 ff ff d0 85 99 05 00 88 ff ff d0 85 99 > 05 00 88 ff ff e0 85 99 05 00 88 ff ff e0 85 99 05 00 88 ff ff <f0> 85 99 05 00 88 ff > ff f0 85 99 05 00 88 ff ff 00 86 99 05 00 > [ 55.922505] RIP: 0xffff8800059985f0 RSP: ffffc9000539be00 > [ 55.922505] CR2: ffff8800059985f0 > [ 55.922505] ---[ end trace 25226e00af3f94fb ]--- > [ 55.933590] Kernel panic - not syncing: Fatal exception > [ 55.933590] Kernel Offset: disabled > [ 55.933590] ---[ end Kernel panic - not syncing: Fatal exception > > So it seems that during > > while (READ_ONCE(channel->probe_done) == false) { > /* > * We wait here until any channel offer is currently > * being processed. > */ > msleep(1); > } > > loop the channel disappeared. The issue may not be related to the netvsc > hang I mentioned before. It may make sense to do refcounting for > channels/subchannels (or employ RCU). I will work on this issue and get you a patch to try. K. Y > > -- > Vitaly _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
