Messages in this thread | | | Subject | Re: general protection fault in tomoyo_socket_sendmsg_permission | From | Shuah Khan <> | Date | Fri, 29 Jan 2021 14:18:09 -0700 |
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On 1/29/21 10:08 AM, Tetsuo Handa wrote: > On 2021/01/30 1:05, Shuah Khan wrote: >>> Since "general protection fault in tomoyo_socket_sendmsg_permission" is caused by >>> unexpectedly resetting ud->tcp_socket to NULL without waiting for tx thread to >>> terminate, tracing the ordering of events is worth knowing. Even adding >>> schedule_timeout_uninterruptible() to before kernel_sendmsg() might help. >>> >> >> What about the duplicate bug information that was in my email? >> Did you take a look at that? > > I was not aware of the duplicate bugs. It is interesting that > "KASAN: null-ptr-deref Write in event_handler" says that vdev->ud.tcp_tx became NULL at > > if (vdev->ud.tcp_tx) { > > /* this location */ > > kthread_stop_put(vdev->ud.tcp_tx); > vdev->ud.tcp_tx = NULL; > } > > which means that somebody else is unexpectedly resetting vdev->ud.tcp_tx to NULL. > > If memset() from vhci_device_init() from vhci_start() were unexpectedly called, > all of tcp_socket, tcp_rx, tcp_tx etc. becomes NULL which can explain these bugs ? > I'm inclined to report not only tcp_socket but also other fields when kernel_sendmsg() > detected that tcp_socket is NULL... >
In this console log:
06:57:50 executing program 1: socketpair$tipc(0x1e, 0x2, 0x0, &(0x7f00000000c0)={<r0=>0xffffffffffffffff}) sendmsg$BATADV_CMD_GET_TRANSTABLE_LOCAL(r0, &(0x7f00000002c0)={&(0x7f00000001c0), 0xc, &(0x7f0000000280)={0x0, 0xd001010000000000}}, 0x0)
[ 1151.090883][T23361] vhci_hcd vhci_hcd.0: pdev(4) rhport(0) sockfd(4) [ 1151.097445][T23361] vhci_hcd vhci_hcd.0: devid(0) speed(1) speed_str(low-speed) 06:57:50 executing program 0: r0 = syz_open_dev$binderN(&(0x7f0000000680)='/dev/binder#\x00', 0x0, 0x0) ioctl$BINDER_WRITE_READ(r0, 0xc0306201, &(0x7f0000000cc0)={0x88, 0x0, &(0x7f0000000b80)=[@transaction={0x40406300, {0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}, @transaction={0x40406300, {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}], 0x0, 0x0, 0x0})
[ 1151.164402][T23363] vhci_hcd: connection closed [ 1151.167346][ T240] vhci_hcd: stop threads
[ 1151.178329][T26761] usb 17-1: new low-speed USB device number 2 using vhci_hcd
SK: Looking at the console log, it looks like while connection is being torn down,
[ 1151.181245][ T240] vhci_hcd: release socket
Can you share your your test code for this program: "executing program 1"
Also your setup? Do you run usbip_host and vhci_hcd both?
thanks, -- Shuah
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