linux-stable.git/drivers/usb, branch v4.14.232 Linux kernel stable tree USB: CDC-ACM: fix poison/unpoison imbalance 2021-04-28T10:08:44+00:00 Oliver Neukum oneukum@suse.com 2021-04-21T07:45:13+00:00 cecc65457b80c444ae0135e2892205d3e4959812 commit a8b3b519618f30a87a304c4e120267ce6f8dc68a upstream. suspend() does its poisoning conditionally, resume() does it unconditionally. On a device with combined interfaces this will balance, on a device with two interfaces the counter will go negative and resubmission will fail. Both actions need to be done conditionally. Fixes: 6069e3e927c8f ("USB: cdc-acm: untangle a circular dependency between callback and softint") Signed-off-by: Oliver Neukum <oneukum@suse.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20210421074513.4327-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a8b3b519618f30a87a304c4e120267ce6f8dc68a upstream.

suspend() does its poisoning conditionally, resume() does it
unconditionally. On a device with combined interfaces this
will balance, on a device with two interfaces the counter will
go negative and resubmission will fail.

Both actions need to be done conditionally.

Fixes: 6069e3e927c8f ("USB: cdc-acm: untangle a circular dependency between callback and softint")
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210421074513.4327-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usbip: Fix incorrect double assignment to udc->ud.tcp_rx 2021-04-28T10:08:41+00:00 Colin Ian King colin.king@canonical.com 2021-03-11T10:44:45+00:00 1a561c5aa1241411ba9736f4739e157524756722 commit 9858af27e69247c5d04c3b093190a93ca365f33d upstream. Currently udc->ud.tcp_rx is being assigned twice, the second assignment is incorrect, it should be to udc->ud.tcp_tx instead of rx. Fix this. Fixes: 46613c9dfa96 ("usbip: fix vudc usbip_sockfd_store races leading to gpf") Acked-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Colin Ian King <colin.king@canonical.com> Cc: stable <stable@vger.kernel.org> Addresses-Coverity: ("Unused value") Link: https://lore.kernel.org/r/20210311104445.7811-1-colin.king@canonical.com Signed-off-by: Tom Seewald <tseewald@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9858af27e69247c5d04c3b093190a93ca365f33d upstream.

Currently udc->ud.tcp_rx is being assigned twice, the second assignment
is incorrect, it should be to udc->ud.tcp_tx instead of rx. Fix this.

Fixes: 46613c9dfa96 ("usbip: fix vudc usbip_sockfd_store races leading to gpf")
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: stable <stable@vger.kernel.org>
Addresses-Coverity: ("Unused value")
Link: https://lore.kernel.org/r/20210311104445.7811-1-colin.king@canonical.com
Signed-off-by: Tom Seewald <tseewald@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usbip: fix vudc usbip_sockfd_store races leading to gpf 2021-04-16T09:57:51+00:00 Shuah Khan skhan@linuxfoundation.org 2021-03-08T03:53:31+00:00 e9c1341b4c948c20f030b6b146fa82575e2fc37b commit 46613c9dfa964c0c60b5385dbdf5aaa18be52a9c upstream. usbip_sockfd_store() is invoked when user requests attach (import) detach (unimport) usb gadget device from usbip host. vhci_hcd sends import request and usbip_sockfd_store() exports the device if it is free for export. Export and unexport are governed by local state and shared state - Shared state (usbip device status, sockfd) - sockfd and Device status are used to determine if stub should be brought up or shut down. Device status is shared between host and client. - Local state (tcp_socket, rx and tx thread task_struct ptrs) A valid tcp_socket controls rx and tx thread operations while the device is in exported state. - While the device is exported, device status is marked used and socket, sockfd, and thread pointers are valid. Export sequence (stub-up) includes validating the socket and creating receive (rx) and transmit (tx) threads to talk to the client to provide access to the exported device. rx and tx threads depends on local and shared state to be correct and in sync. Unexport (stub-down) sequence shuts the socket down and stops the rx and tx threads. Stub-down sequence relies on local and shared states to be in sync. There are races in updating the local and shared status in the current stub-up sequence resulting in crashes. These stem from starting rx and tx threads before local and global state is updated correctly to be in sync. 1. Doesn't handle kthread_create() error and saves invalid ptr in local state that drives rx and tx threads. 2. Updates tcp_socket and sockfd, starts stub_rx and stub_tx threads before updating usbip_device status to SDEV_ST_USED. This opens up a race condition between the threads and usbip_sockfd_store() stub up and down handling. Fix the above problems: - Stop using kthread_get_run() macro to create/start threads. - Create threads and get task struct reference. - Add kthread_create() failure handling and bail out. - Hold usbip_device lock to update local and shared states after creating rx and tx threads. - Update usbip_device status to SDEV_ST_USED. - Update usbip_device tcp_socket, sockfd, tcp_rx, and tcp_tx - Start threads after usbip_device (tcp_socket, sockfd, tcp_rx, tcp_tx, and status) is complete. Credit goes to syzbot and Tetsuo Handa for finding and root-causing the kthread_get_run() improper error handling problem and others. This is a hard problem to find and debug since the races aren't seen in a normal case. Fuzzing forces the race window to be small enough for the kthread_get_run() error path bug and starting threads before updating the local and shared state bug in the stub-up sequence. Fixes: 9720b4bc76a83807 ("staging/usbip: convert to kthread") Cc: stable@vger.kernel.org Reported-by: syzbot <syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com> Reported-by: syzbot <syzbot+bf1a360e305ee719e364@syzkaller.appspotmail.com> Reported-by: syzbot <syzbot+95ce4b142579611ef0a9@syzkaller.appspotmail.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Link: https://lore.kernel.org/r/b1c08b983ffa185449c9f0f7d1021dc8c8454b60.1615171203.git.skhan@linuxfoundation.org Signed-off-by: Tom Seewald <tseewald@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 46613c9dfa964c0c60b5385dbdf5aaa18be52a9c upstream.

usbip_sockfd_store() is invoked when user requests attach (import)
detach (unimport) usb gadget device from usbip host. vhci_hcd sends
import request and usbip_sockfd_store() exports the device if it is
free for export.

Export and unexport are governed by local state and shared state
- Shared state (usbip device status, sockfd) - sockfd and Device
  status are used to determine if stub should be brought up or shut
  down. Device status is shared between host and client.
- Local state (tcp_socket, rx and tx thread task_struct ptrs)
  A valid tcp_socket controls rx and tx thread operations while the
  device is in exported state.
- While the device is exported, device status is marked used and socket,
  sockfd, and thread pointers are valid.

Export sequence (stub-up) includes validating the socket and creating
receive (rx) and transmit (tx) threads to talk to the client to provide
access to the exported device. rx and tx threads depends on local and
shared state to be correct and in sync.

Unexport (stub-down) sequence shuts the socket down and stops the rx and
tx threads. Stub-down sequence relies on local and shared states to be
in sync.

There are races in updating the local and shared status in the current
stub-up sequence resulting in crashes. These stem from starting rx and
tx threads before local and global state is updated correctly to be in
sync.

1. Doesn't handle kthread_create() error and saves invalid ptr in local
   state that drives rx and tx threads.
2. Updates tcp_socket and sockfd,  starts stub_rx and stub_tx threads
   before updating usbip_device status to SDEV_ST_USED. This opens up a
   race condition between the threads and usbip_sockfd_store() stub up
   and down handling.

Fix the above problems:
- Stop using kthread_get_run() macro to create/start threads.
- Create threads and get task struct reference.
- Add kthread_create() failure handling and bail out.
- Hold usbip_device lock to update local and shared states after
  creating rx and tx threads.
- Update usbip_device status to SDEV_ST_USED.
- Update usbip_device tcp_socket, sockfd, tcp_rx, and tcp_tx
- Start threads after usbip_device (tcp_socket, sockfd, tcp_rx, tcp_tx,
  and status) is complete.

Credit goes to syzbot and Tetsuo Handa for finding and root-causing the
kthread_get_run() improper error handling problem and others. This is a
hard problem to find and debug since the races aren't seen in a normal
case. Fuzzing forces the race window to be small enough for the
kthread_get_run() error path bug and starting threads before updating the
local and shared state bug in the stub-up sequence.

Fixes: 9720b4bc76a83807 ("staging/usbip: convert to kthread")
Cc: stable@vger.kernel.org
Reported-by: syzbot <syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+bf1a360e305ee719e364@syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+95ce4b142579611ef0a9@syzkaller.appspotmail.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/b1c08b983ffa185449c9f0f7d1021dc8c8454b60.1615171203.git.skhan@linuxfoundation.org
Signed-off-by: Tom Seewald <tseewald@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usbip: synchronize event handler with sysfs code paths 2021-04-16T09:57:49+00:00 Shuah Khan skhan@linuxfoundation.org 2021-03-30T01:36:51+00:00 534d2cf487b972b2c039bfc55898a7edc2b0ea45 commit 363eaa3a450abb4e63bd6e3ad79d1f7a0f717814 upstream. Fuzzing uncovered race condition between sysfs code paths in usbip drivers. Device connect/disconnect code paths initiated through sysfs interface are prone to races if disconnect happens during connect and vice versa. Use sysfs_lock to synchronize event handler with sysfs paths in usbip drivers. Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Link: https://lore.kernel.org/r/c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 363eaa3a450abb4e63bd6e3ad79d1f7a0f717814 upstream.

Fuzzing uncovered race condition between sysfs code paths in usbip
drivers. Device connect/disconnect code paths initiated through
sysfs interface are prone to races if disconnect happens during
connect and vice versa.

Use sysfs_lock to synchronize event handler with sysfs paths
in usbip drivers.

Cc: stable@vger.kernel.org
Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/c5c8723d3f29dfe3d759cfaafa7dd16b0dfe2918.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usbip: stub-dev synchronize sysfs code paths 2021-04-16T09:57:49+00:00 Shuah Khan skhan@linuxfoundation.org 2021-03-30T01:36:49+00:00 fbf3417833b0fb3a2a00377e50622551aaedc0e5 commit 9dbf34a834563dada91366c2ac266f32ff34641a upstream. Fuzzing uncovered race condition between sysfs code paths in usbip drivers. Device connect/disconnect code paths initiated through sysfs interface are prone to races if disconnect happens during connect and vice versa. Use sysfs_lock to protect sysfs paths in stub-dev. Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Link: https://lore.kernel.org/r/2b182f3561b4a065bf3bf6dce3b0e9944ba17b3f.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9dbf34a834563dada91366c2ac266f32ff34641a upstream.

Fuzzing uncovered race condition between sysfs code paths in usbip
drivers. Device connect/disconnect code paths initiated through
sysfs interface are prone to races if disconnect happens during
connect and vice versa.

Use sysfs_lock to protect sysfs paths in stub-dev.

Cc: stable@vger.kernel.org
Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/2b182f3561b4a065bf3bf6dce3b0e9944ba17b3f.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usbip: add sysfs_lock to synchronize sysfs code paths 2021-04-16T09:57:49+00:00 Shuah Khan skhan@linuxfoundation.org 2021-03-30T01:36:48+00:00 5f2a149564ee2b41ab09e90add21153bd5be64d3 commit 4e9c93af7279b059faf5bb1897ee90512b258a12 upstream. Fuzzing uncovered race condition between sysfs code paths in usbip drivers. Device connect/disconnect code paths initiated through sysfs interface are prone to races if disconnect happens during connect and vice versa. This problem is common to all drivers while it can be reproduced easily in vhci_hcd. Add a sysfs_lock to usbip_device struct to protect the paths. Use this in vhci_hcd to protect sysfs paths. For a complete fix, usip_host and usip-vudc drivers and the event handler will have to use this lock to protect the paths. These changes will be done in subsequent patches. Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Link: https://lore.kernel.org/r/b6568f7beae702bbc236a545d3c020106ca75eac.1616807117.git.skhan@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4e9c93af7279b059faf5bb1897ee90512b258a12 upstream.

Fuzzing uncovered race condition between sysfs code paths in usbip
drivers. Device connect/disconnect code paths initiated through
sysfs interface are prone to races if disconnect happens during
connect and vice versa.

This problem is common to all drivers while it can be reproduced easily
in vhci_hcd. Add a sysfs_lock to usbip_device struct to protect the paths.

Use this in vhci_hcd to protect sysfs paths. For a complete fix, usip_host
and usip-vudc drivers and the event handler will have to use this lock to
protect the paths. These changes will be done in subsequent patches.

Cc: stable@vger.kernel.org
Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/b6568f7beae702bbc236a545d3c020106ca75eac.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: udc: amd5536udc_pci fix null-ptr-dereference 2021-04-07T10:47:04+00:00 Tong Zhang ztong0001@gmail.com 2021-03-17T23:04:00+00:00 6b4aa86542b4659d8c95e41f2c75a7d7dd969133 commit 72035f4954f0bca2d8c47cf31b3629c42116f5b7 upstream. init_dma_pools() calls dma_pool_create(...dev->dev) to create dma pool. however, dev->dev is actually set after calling init_dma_pools(), which effectively makes dma_pool_create(..NULL) and cause crash. To fix this issue, init dma only after dev->dev is set. [ 1.317993] RIP: 0010:dma_pool_create+0x83/0x290 [ 1.323257] Call Trace: [ 1.323390] ? pci_write_config_word+0x27/0x30 [ 1.323626] init_dma_pools+0x41/0x1a0 [snps_udc_core] [ 1.323899] udc_pci_probe+0x202/0x2b1 [amd5536udc_pci] Fixes: 7c51247a1f62 (usb: gadget: udc: Provide correct arguments for 'dma_pool_create') Cc: stable <stable@vger.kernel.org> Signed-off-by: Tong Zhang <ztong0001@gmail.com> Link: https://lore.kernel.org/r/20210317230400.357756-1-ztong0001@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 72035f4954f0bca2d8c47cf31b3629c42116f5b7 upstream.

init_dma_pools() calls dma_pool_create(...dev->dev) to create dma pool.
however, dev->dev is actually set after calling init_dma_pools(), which
effectively makes dma_pool_create(..NULL) and cause crash.
To fix this issue, init dma only after dev->dev is set.

[    1.317993] RIP: 0010:dma_pool_create+0x83/0x290
[    1.323257] Call Trace:
[    1.323390]  ? pci_write_config_word+0x27/0x30
[    1.323626]  init_dma_pools+0x41/0x1a0 [snps_udc_core]
[    1.323899]  udc_pci_probe+0x202/0x2b1 [amd5536udc_pci]

Fixes: 7c51247a1f62 (usb: gadget: udc: Provide correct arguments for 'dma_pool_create')
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Link: https://lore.kernel.org/r/20210317230400.357756-1-ztong0001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: cdc-acm: fix use-after-free after probe failure 2021-04-07T10:47:04+00:00 Johan Hovold johan@kernel.org 2021-03-22T15:53:12+00:00 a110a1d03ac71d10ff18b0e3983efec607093187 commit 4e49bf376c0451ad2eae2592e093659cde12be9a upstream. If tty-device registration fails the driver would fail to release the data interface. When the device is later disconnected, the disconnect callback would still be called for the data interface and would go about releasing already freed resources. Fixes: c93d81955005 ("usb: cdc-acm: fix error handling in acm_probe()") Cc: stable@vger.kernel.org # 3.9 Cc: Alexey Khoroshilov <khoroshilov@ispras.ru> Acked-by: Oliver Neukum <oneukum@suse.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210322155318.9837-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4e49bf376c0451ad2eae2592e093659cde12be9a upstream.

If tty-device registration fails the driver would fail to release the
data interface. When the device is later disconnected, the disconnect
callback would still be called for the data interface and would go about
releasing already freed resources.

Fixes: c93d81955005 ("usb: cdc-acm: fix error handling in acm_probe()")
Cc: stable@vger.kernel.org      # 3.9
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210322155318.9837-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: cdc-acm: downgrade message to debug 2021-04-07T10:47:04+00:00 Oliver Neukum oneukum@suse.com 2021-03-11T13:01:26+00:00 88fc6e1ae2ff99d595ca07a3a572cd6f8caac90d commit e4c77070ad45fc940af1d7fb1e637c349e848951 upstream. This failure is so common that logging an error here amounts to spamming log files. Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com> Signed-off-by: Oliver Neukum <oneukum@suse.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20210311130126.15972-2-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e4c77070ad45fc940af1d7fb1e637c349e848951 upstream.

This failure is so common that logging an error here amounts
to spamming log files.

Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210311130126.15972-2-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: cdc-acm: untangle a circular dependency between callback and softint 2021-04-07T10:47:04+00:00 Oliver Neukum oneukum@suse.com 2021-03-11T13:01:25+00:00 0ea160742f4b3539a7977d3d45fb75b07de4e76e commit 6069e3e927c8fb3a1947b07d1a561644ea960248 upstream. We have a cycle of callbacks scheduling works which submit URBs with thos callbacks. This needs to be blocked, stopped and unblocked to untangle the circle. The issue leads to faults like: [ 55.068392] Unable to handle kernel paging request at virtual address 6b6b6c03 [ 55.075624] pgd = be866494 [ 55.078335] [6b6b6c03] *pgd=00000000 [ 55.081924] Internal error: Oops: 5 [#1] PREEMPT SMP ARM [ 55.087238] Modules linked in: ppp_async crc_ccitt ppp_generic slhc xt_TCPMSS xt_tcpmss xt_hl nf_log_ipv6 nf_log_ipv4 nf_log_common xt_policy xt_limit xt_conntrack xt_tcpudp xt_pkttype ip6table_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle ip6table_filter ip6_tables iptable_filter ip_tables des_generic md5 sch_fq_codel cdc_mbim cdc_wdm cdc_ncm usbnet mii cdc_acm usb_storage ip_tunnel xfrm_user xfrm6_tunnel tunnel6 xfrm4_tunnel tunnel4 esp6 esp4 ah6 ah4 xfrm_algo xt_LOG xt_LED xt_comment x_tables ipv6 [ 55.134954] CPU: 0 PID: 82 Comm: kworker/0:2 Tainted: G T 5.8.17 #1 [ 55.142526] Hardware name: Freescale i.MX7 Dual (Device Tree) [ 55.148304] Workqueue: events acm_softint [cdc_acm] [ 55.153196] PC is at kobject_get+0x10/0xa4 [ 55.157302] LR is at usb_get_dev+0x14/0x1c [ 55.161402] pc : [<8047c06c>] lr : [<80560448>] psr: 20000193 [ 55.167671] sp : bca39ea8 ip : 00007374 fp : bf6cbd80 [ 55.172899] r10: 00000000 r9 : bdd92284 r8 : bdd92008 [ 55.178128] r7 : 6b6b6b6b r6 : fffffffe r5 : 60000113 r4 : 6b6b6be3 [ 55.184658] r3 : 6b6b6b6b r2 : 00000111 r1 : 00000000 r0 : 6b6b6be3 [ 55.191191] Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment none [ 55.198417] Control: 10c5387d Table: bcf0c06a DAC: 00000051 [ 55.204168] Process kworker/0:2 (pid: 82, stack limit = 0x9bdd2a89) [ 55.210439] Stack: (0xbca39ea8 to 0xbca3a000) [ 55.214805] 9ea0: bf6cbd80 80769a50 6b6b6b6b 80560448 bdeb0500 8056bfe8 [ 55.222991] 9ec0: 00000002 b76da000 00000000 bdeb0500 bdd92448 bca38000 bdeb0510 8056d69c [ 55.231177] 9ee0: bca38000 00000000 80c050fc 00000000 bca39f44 09d42015 00000000 00000001 [ 55.239363] 9f00: bdd92448 bdd92438 bdd92000 7f1158c4 bdd92448 bca2ee00 bf6cbd80 bf6cef00 [ 55.247549] 9f20: 00000000 00000000 00000000 801412d8 bf6cbd98 80c03d00 bca2ee00 bf6cbd80 [ 55.255735] 9f40: bca2ee14 bf6cbd98 80c03d00 00000008 bca38000 80141568 00000000 80c446ae [ 55.263921] 9f60: 00000000 bc9ed880 bc9f0700 bca38000 bc117eb4 80141524 bca2ee00 bc9ed8a4 [ 55.272107] 9f80: 00000000 80147cc8 00000000 bc9f0700 80147b84 00000000 00000000 00000000 [ 55.280292] 9fa0: 00000000 00000000 00000000 80100148 00000000 00000000 00000000 00000000 [ 55.288477] 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 55.296662] 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 [ 55.304860] [<8047c06c>] (kobject_get) from [<80560448>] (usb_get_dev+0x14/0x1c) [ 55.312271] [<80560448>] (usb_get_dev) from [<8056bfe8>] (usb_hcd_unlink_urb+0x50/0xd8) [ 55.320286] [<8056bfe8>] (usb_hcd_unlink_urb) from [<8056d69c>] (usb_kill_urb.part.0+0x44/0xd0) [ 55.329004] [<8056d69c>] (usb_kill_urb.part.0) from [<7f1158c4>] (acm_softint+0x4c/0x10c [cdc_acm]) [ 55.338082] [<7f1158c4>] (acm_softint [cdc_acm]) from [<801412d8>] (process_one_work+0x19c/0x3e8) [ 55.346969] [<801412d8>] (process_one_work) from [<80141568>] (worker_thread+0x44/0x4dc) [ 55.355072] [<80141568>] (worker_thread) from [<80147cc8>] (kthread+0x144/0x180) [ 55.362481] [<80147cc8>] (kthread) from [<80100148>] (ret_from_fork+0x14/0x2c) [ 55.369706] Exception stack(0xbca39fb0 to 0xbca39ff8) Tested-by: Bruno Thomsen <bruno.thomsen@gmail.com> Signed-off-by: Oliver Neukum <oneukum@suse.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20210311130126.15972-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6069e3e927c8fb3a1947b07d1a561644ea960248 upstream.

We have a cycle of callbacks scheduling works which submit
URBs with thos callbacks. This needs to be blocked, stopped
and unblocked to untangle the circle.

The issue leads to faults like:

[   55.068392] Unable to handle kernel paging request at virtual address 6b6b6c03
[   55.075624] pgd = be866494
[   55.078335] [6b6b6c03] *pgd=00000000
[   55.081924] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[   55.087238] Modules linked in: ppp_async crc_ccitt ppp_generic slhc
xt_TCPMSS xt_tcpmss xt_hl nf_log_ipv6 nf_log_ipv4 nf_log_common
xt_policy xt_limit xt_conntrack xt_tcpudp xt_pkttype ip6table_mangle
iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
iptable_mangle ip6table_filter ip6_tables iptable_filter ip_tables
des_generic md5 sch_fq_codel cdc_mbim cdc_wdm cdc_ncm usbnet mii
cdc_acm usb_storage ip_tunnel xfrm_user xfrm6_tunnel tunnel6
xfrm4_tunnel tunnel4 esp6 esp4 ah6 ah4 xfrm_algo xt_LOG xt_LED
xt_comment x_tables ipv6
[   55.134954] CPU: 0 PID: 82 Comm: kworker/0:2 Tainted: G
   T 5.8.17 #1
[   55.142526] Hardware name: Freescale i.MX7 Dual (Device Tree)
[   55.148304] Workqueue: events acm_softint [cdc_acm]
[   55.153196] PC is at kobject_get+0x10/0xa4
[   55.157302] LR is at usb_get_dev+0x14/0x1c
[   55.161402] pc : [<8047c06c>]    lr : [<80560448>]    psr: 20000193
[   55.167671] sp : bca39ea8  ip : 00007374  fp : bf6cbd80
[   55.172899] r10: 00000000  r9 : bdd92284  r8 : bdd92008
[   55.178128] r7 : 6b6b6b6b  r6 : fffffffe  r5 : 60000113  r4 : 6b6b6be3
[   55.184658] r3 : 6b6b6b6b  r2 : 00000111  r1 : 00000000  r0 : 6b6b6be3
[   55.191191] Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM Segment none
[   55.198417] Control: 10c5387d  Table: bcf0c06a  DAC: 00000051
[   55.204168] Process kworker/0:2 (pid: 82, stack limit = 0x9bdd2a89)
[   55.210439] Stack: (0xbca39ea8 to 0xbca3a000)
[   55.214805] 9ea0:                   bf6cbd80 80769a50 6b6b6b6b 80560448 bdeb0500 8056bfe8
[   55.222991] 9ec0: 00000002 b76da000 00000000 bdeb0500 bdd92448 bca38000 bdeb0510 8056d69c
[   55.231177] 9ee0: bca38000 00000000 80c050fc 00000000 bca39f44 09d42015 00000000 00000001
[   55.239363] 9f00: bdd92448 bdd92438 bdd92000 7f1158c4 bdd92448 bca2ee00 bf6cbd80 bf6cef00
[   55.247549] 9f20: 00000000 00000000 00000000 801412d8 bf6cbd98 80c03d00 bca2ee00 bf6cbd80
[   55.255735] 9f40: bca2ee14 bf6cbd98 80c03d00 00000008 bca38000 80141568 00000000 80c446ae
[   55.263921] 9f60: 00000000 bc9ed880 bc9f0700 bca38000 bc117eb4 80141524 bca2ee00 bc9ed8a4
[   55.272107] 9f80: 00000000 80147cc8 00000000 bc9f0700 80147b84 00000000 00000000 00000000
[   55.280292] 9fa0: 00000000 00000000 00000000 80100148 00000000 00000000 00000000 00000000
[   55.288477] 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[   55.296662] 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[   55.304860] [<8047c06c>] (kobject_get) from [<80560448>] (usb_get_dev+0x14/0x1c)
[   55.312271] [<80560448>] (usb_get_dev) from [<8056bfe8>] (usb_hcd_unlink_urb+0x50/0xd8)
[   55.320286] [<8056bfe8>] (usb_hcd_unlink_urb) from [<8056d69c>] (usb_kill_urb.part.0+0x44/0xd0)
[   55.329004] [<8056d69c>] (usb_kill_urb.part.0) from [<7f1158c4>] (acm_softint+0x4c/0x10c [cdc_acm])
[   55.338082] [<7f1158c4>] (acm_softint [cdc_acm]) from [<801412d8>] (process_one_work+0x19c/0x3e8)
[   55.346969] [<801412d8>] (process_one_work) from [<80141568>] (worker_thread+0x44/0x4dc)
[   55.355072] [<80141568>] (worker_thread) from [<80147cc8>] (kthread+0x144/0x180)
[   55.362481] [<80147cc8>] (kthread) from [<80100148>] (ret_from_fork+0x14/0x2c)
[   55.369706] Exception stack(0xbca39fb0 to 0xbca39ff8)

Tested-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210311130126.15972-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>