From: Zhengjun Xing zhengjun.xing@linux.intel.com

commit 44a182b9d177 ("xhci: Fix use-after-free in xhci_free_virt_device") set dev->udev pointer to NULL in xhci_free_dev(), it will cause kernel panic in trace_xhci_free_virt_device. This patch reimplement the trace function trace_xhci_free_virt_device, remove dev->udev dereference and added more useful parameters to show in the trace function,it also makes sure dev->udev is not NULL before calling trace_xhci_free_virt_device. This issue happened when xhci-hcd trace is enabled and USB devices hot plug test. Original use-after-free patch went to stable so this needs so be applied there as well.

[ 1092.022457] usb 2-4: USB disconnect, device number 6 [ 1092.092772] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 [ 1092.101694] PGD 0 P4D 0 [ 1092.104601] Oops: 0000 [#1] SMP [ 1092.207734] Workqueue: usb_hub_wq hub_event [ 1092.212507] RIP: 0010:trace_event_raw_event_xhci_log_virt_dev+0x6c/0xf0 [ 1092.220050] RSP: 0018:ffff8c252e883d28 EFLAGS: 00010086 [ 1092.226024] RAX: ffff8c24af86fa84 RBX: 0000000000000003 RCX: ffff8c25255c2a01 [ 1092.234130] RDX: 0000000000000000 RSI: 00000000aef55009 RDI: ffff8c252e883d28 [ 1092.242242] RBP: ffff8c252550e2c0 R08: ffff8c24af86fa84 R09: 0000000000000a70 [ 1092.250364] R10: 0000000000000a70 R11: 0000000000000000 R12: ffff8c251f21a000 [ 1092.258468] R13: 000000000000000c R14: ffff8c251f21a000 R15: ffff8c251f432f60 [ 1092.266572] FS: 0000000000000000(0000) GS:ffff8c252e880000(0000) knlGS:0000000000000000 [ 1092.275757] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1092.282281] CR2: 0000000000000000 CR3: 0000000154209001 CR4: 00000000003606e0 [ 1092.290384] Call Trace: [ 1092.293156] <IRQ> [ 1092.295439] xhci_free_virt_device.part.34+0x182/0x1a0 [ 1092.301288] handle_cmd_completion+0x7ac/0xfa0 [ 1092.306336] ? trace_event_raw_event_xhci_log_trb+0x6e/0xa0 [ 1092.312661] xhci_irq+0x3e8/0x1f60 [ 1092.316524] __handle_irq_event_percpu+0x75/0x180 [ 1092.321876] handle_irq_event_percpu+0x20/0x50 [ 1092.326922] handle_irq_event+0x36/0x60 [ 1092.331273] handle_edge_irq+0x6d/0x180 [ 1092.335644] handle_irq+0x16/0x20 [ 1092.339417] do_IRQ+0x41/0xc0 [ 1092.342782] common_interrupt+0xf/0xf [ 1092.346955] </IRQ>

Fixes: 44a182b9d177 ("xhci: Fix use-after-free in xhci_free_virt_device") Cc: stable@vger.kernel.org Signed-off-by: Zhengjun Xing zhengjun.xing@linux.intel.com Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com --- drivers/usb/host/xhci-mem.c | 4 ++-- drivers/usb/host/xhci-trace.h | 36 +++++++++++++++++++++++++++++++----- 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index acbd3d7..8a62eee 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -886,12 +886,12 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)

dev = xhci->devs[slot_id];

- trace_xhci_free_virt_device(dev); - xhci->dcbaa->dev_context_ptrs[slot_id] = 0; if (!dev) return;

+ trace_xhci_free_virt_device(dev); + if (dev->tt_info) old_active_eps = dev->tt_info->active_eps;

diff --git a/drivers/usb/host/xhci-trace.h b/drivers/usb/host/xhci-trace.h index 410544f..88b4274 100644 --- a/drivers/usb/host/xhci-trace.h +++ b/drivers/usb/host/xhci-trace.h @@ -171,6 +171,37 @@ DEFINE_EVENT(xhci_log_trb, xhci_dbc_gadget_ep_queue, TP_ARGS(ring, trb) );

+DECLARE_EVENT_CLASS(xhci_log_free_virt_dev, + TP_PROTO(struct xhci_virt_device *vdev), + TP_ARGS(vdev), + TP_STRUCT__entry( + __field(void *, vdev) + __field(unsigned long long, out_ctx) + __field(unsigned long long, in_ctx) + __field(u8, fake_port) + __field(u8, real_port) + __field(u16, current_mel) + + ), + TP_fast_assign( + __entry->vdev = vdev; + __entry->in_ctx = (unsigned long long) vdev->in_ctx->dma; + __entry->out_ctx = (unsigned long long) vdev->out_ctx->dma; + __entry->fake_port = (u8) vdev->fake_port; + __entry->real_port = (u8) vdev->real_port; + __entry->current_mel = (u16) vdev->current_mel; + ), + TP_printk("vdev %p ctx %llx | %llx fake_port %d real_port %d current_mel %d", + __entry->vdev, __entry->in_ctx, __entry->out_ctx, + __entry->fake_port, __entry->real_port, __entry->current_mel + ) +); + +DEFINE_EVENT(xhci_log_free_virt_dev, xhci_free_virt_device, + TP_PROTO(struct xhci_virt_device *vdev), + TP_ARGS(vdev) +); + DECLARE_EVENT_CLASS(xhci_log_virt_dev, TP_PROTO(struct xhci_virt_device *vdev), TP_ARGS(vdev), @@ -208,11 +239,6 @@ DEFINE_EVENT(xhci_log_virt_dev, xhci_alloc_virt_device, TP_ARGS(vdev) );

-DEFINE_EVENT(xhci_log_virt_dev, xhci_free_virt_device, - TP_PROTO(struct xhci_virt_device *vdev), - TP_ARGS(vdev) -); - DEFINE_EVENT(xhci_log_virt_dev, xhci_setup_device, TP_PROTO(struct xhci_virt_device *vdev), TP_ARGS(vdev)