Re-sending, hopefully without multi-part now, so it gets to the list. Temporarily forced into using a different mail client... On Tue, Aug 4, 2015 at 10:05 AM, Jarod Wilson <jarod@xxxxxxxxxx> wrote: > On Mon, Aug 3, 2015 at 12:14 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: >> >> On Tue, Jul 21, 2015 at 12:25:30PM -0400, Jarod Wilson wrote: >> > https://bugzilla.kernel.org/show_bug.cgi?id=99841 >> > >> > Seems like a read of all 1's from a register of a device that has gone >> > away should be taken as a sign that the device has gone away. >> > Section 6.2.10 of the PCIE spec (v4.0, rev 0.3, Feb 19, 2014) suggests >> > as >> > much with this snippet: >> > >> > |IMPLEMENTATION NOTE >> > |Data Value of All 1’s >> > |Many platforms, including those supporting RP Extensions for DPC, can >> > |return a data value of all 1’s to software when an error is associated >> > |with a PCI Express Configuration, I/O, or Memory Read Request. During >> > DPC, >> > |the Downstream Port discards Requests destined for the Link and >> > completes >> > |them with an error (i.e., either with an Unsupported Request (UR) or >> > |Completer Abort (CA) Completion Status). By ending a series of MMIO or >> > |configuration space operations with a read to an address with a known >> > |data value not equal to all 1’s, software may determine if a Completer >> > |has been removed or DPC has been triggered. >> > >> > I'm not sure the above is directly relevant to this case, but the same >> > principle (reading all 1's means the device is probably gone) seems to >> > hold. >> > >> > This is based on part of a debugging patch Bjorn posted in the >> > referenced >> > bugzilla, and its required to make the HP ZBook G2 I've got here not >> > barf >> > when disconnecting a thunderbolt ethernet adapter and corrupt memory. >> > >> > Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> >> > CC: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> >> > CC: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >> > CC: linux-pci@xxxxxxxxxxxxxxx >> > Signed-off-by: Jarod Wilson <jarod@xxxxxxxxxx> >> >> Hi Jarod, >> >> I think there are two issues here: >> >> 1) pciehp doesn't handle all 1's correctly >> 2) use-after-free of hotplug_slot >> >> This patch is for the first issue. I think it's correct, but I still >> have a question or two. I attached an updated version of the patch >> and changelog. >> >> Here's the path I think we're taking: 03:03.0 receives pciehp >> interrupt for removal (link down and card not present), and we call >> pciehp_unconfigure_device() for 05:00.0 and everything downstream from >> it. Part of this is removing 06:00.0. I expected this would use this >> path: >> >> pcie_port_remove_service # .remove method for 06:00.0 >> dev_printk("unloading service driver ...") >> pciehp_remove # hpdriver_portdrv.remove >> pciehp_release_ctrl >> pcie_shutdown_notification >> pcie_disable_notification >> pcie_write_cmd >> pcie_do_write_cmd(..., true) # wait >> pcie_wait_cmd >> pcie_poll_cmd >> read PCI_EXP_SLTSTA # would get 0xffff >> read PCI_EXPT_SLTCTL # would get 0xffff >> >> so I added checks for ~0 data in pcie_poll_cmd() and >> pcie_do_write_cmd(). >> >> But the dmesg log shows that we were in pcie_isr(), and I don't >> understand yet how we got there. Can you help figure that out? Maybe >> put a dump_stack() in pcie_isr() or something? > > > pciehp_power_thread looks to be the entry point. > > [ 1949.102247] pciehp 0000:03:03.0:pcie24: pcie_isr: intr_loc 108 > [ 1949.102252] pciehp 0000:03:03.0:pcie24: Presence/Notify input change > [ 1949.102256] pciehp 0000:03:03.0:pcie24: Card not present on Slot(3) > [ 1949.102262] pciehp 0000:03:03.0:pcie24: Data Link Layer State change > [ 1949.102266] pciehp 0000:03:03.0:pcie24: slot(3): Link Down event > [ 1949.102281] pciehp 0000:03:03.0:pcie24: Surprise Removal > [ 1949.102286] pciehp 0000:03:03.0:pcie24: Link Down event ignored on > slot(3): already powering off > [ 1949.102288] pciehp 0000:03:03.0:pcie24: Disabling > domain:bus:device=0000:05:00 > [ 1949.102290] pciehp 0000:03:03.0:pcie24: pciehp_unconfigure_device: > domain:bus:dev = 0000:05:00 > [ 1950.321907] tg3 0000:07:00.0: tg3_abort_hw timed out, TX_MODE_ENABLE will > not clear MAC_TX_MODE=ffffffff > [ 1950.525986] [sched_delayed] sched: RT throttling activated > [ 1950.544164] pciehp 0000:06:00.0:pcie24: unloading service driver pciehp > [ 1950.544170] pciehp 0000:06:00.0:pcie24: release_slot: physical_slot = 9 > [ 1950.545016] pciehp 0000:06:00.0:pcie24: Timeout on hotplug command 0x1038 > (issued 19092 msec ago) > [ 1950.545020] pciehp 0000:06:00.0:pcie24: pcie_do_write_cmd: no response > from device > [ 1950.545021] pciehp 0000:06:00.0:pcie24: pcie_disable_notification: > SLOTCTRL d8 write cmd 0 > [ 1950.545025] pciehp 0000:06:00.0:pcie24: Device has gone away > [ 1950.545027] CPU: 0 PID: 12361 Comm: kworker/0:2 Not tainted > 3.10.0-302.el7.hp.x86_64 #1 > [ 1950.545028] Hardware name: Hewlett-Packard HP ZBook 15 G2/2253, BIOS M70 > Ver. 01.07 02/26/2015 > [ 1950.545033] Workqueue: pciehp-3 pciehp_power_thread > [ 1950.545034] 0000000000000000 00000000f721dd13 ffff8804822ffa78 > ffffffff81632729 > [ 1950.545036] ffff8804822ffac0 ffffffff8133bf64 ffff00000000002e > 00000000f721dd13 > [ 1950.545038] ffff8804818fab00 ffff880468f70cc0 000000000000002e > 0000000000000282 > [ 1950.545039] Call Trace: > [ 1950.545044] [<ffffffff81632729>] dump_stack+0x19/0x1b > [ 1950.545046] [<ffffffff8133bf64>] pcie_isr+0x264/0x280 > [ 1950.545048] [<ffffffff8111b6b9>] __free_irq+0x189/0x220 > [ 1950.545049] [<ffffffff8111b7e9>] free_irq+0x49/0xb0 > [ 1950.545051] [<ffffffff8133d3b9>] pciehp_release_ctrl+0xb9/0xe0 > [ 1950.545053] [<ffffffff81339db3>] pciehp_remove+0x23/0x30 > [ 1950.545055] [<ffffffff8133442e>] pcie_port_remove_service+0x4e/0x60 > [ 1950.545058] [<ffffffff813f39ff>] __device_release_driver+0x7f/0xf0 > [ 1950.545059] [<ffffffff813f3a93>] device_release_driver+0x23/0x30 > [ 1950.545061] [<ffffffff813f3208>] bus_remove_device+0x108/0x180 > [ 1950.545062] [<ffffffff813ef725>] device_del+0x135/0x1f0 > [ 1950.545064] [<ffffffff81334360>] ? cleanup_service_irqs+0x40/0x40 > [ 1950.545065] [<ffffffff813ef7fe>] device_unregister+0x1e/0x60 > [ 1950.545066] [<ffffffff81334381>] remove_iter+0x21/0x30 > [ 1950.545068] [<ffffffff813ef093>] device_for_each_child+0x53/0x90 > [ 1950.545069] [<ffffffff81334ae2>] pcie_port_device_remove+0x22/0x40 > [ 1950.545070] [<ffffffff81334e1e>] pcie_portdrv_remove+0xe/0x10 > [ 1950.545074] [<ffffffff813266eb>] pci_device_remove+0x3b/0xb0 > [ 1950.545075] [<ffffffff813f39ff>] __device_release_driver+0x7f/0xf0 > [ 1950.545077] [<ffffffff813f3a93>] device_release_driver+0x23/0x30 > [ 1950.545078] [<ffffffff8131fa54>] pci_stop_bus_device+0x94/0xa0 > [ 1950.545079] [<ffffffff8131f9fb>] pci_stop_bus_device+0x3b/0xa0 > [ 1950.545081] [<ffffffff8131fb42>] > pci_stop_and_remove_bus_device+0x12/0x20 > [ 1950.545082] [<ffffffff8133b8a0>] pciehp_unconfigure_device+0xb0/0x1b0 > [ 1950.545084] [<ffffffff8133b282>] pciehp_disable_slot+0x52/0xd0 > [ 1950.545085] [<ffffffff8133b3ea>] pciehp_power_thread+0xea/0x150 > [ 1950.545088] [<ffffffff8109c57b>] process_one_work+0x17b/0x470 > [ 1950.545089] [<ffffffff8109d34b>] worker_thread+0x11b/0x400 > [ 1950.545090] [<ffffffff8109d230>] ? rescuer_thread+0x400/0x400 > [ 1950.545093] [<ffffffff810a4a6f>] kthread+0xcf/0xe0 > [ 1950.545094] [<ffffffff810a49a0>] ? kthread_create_on_node+0x140/0x140 > [ 1950.545097] [<ffffffff81642d58>] ret_from_fork+0x58/0x90 > [ 1950.545099] [<ffffffff810a49a0>] ? kthread_create_on_node+0x140/0x140 > > > I get pretty much identical stacks for these devices as well, in this order > after the above: > [ 1959.103493] pciehp 0000:03:06.0:pcie24: Device has gone away > [ 1959.104152] pciehp 0000:03:05.0:pcie24: Device has gone away > [ 1959.104736] pciehp 0000:03:04.0:pcie24: Device has gone away > [ 1959.105265] pciehp 0000:03:03.0:pcie24: Device has gone away > [ 1959.105841] pciehp 0000:03:00.0:pcie24: Device has gone away > > > --jarod > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
