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Marek Marczykowski-Górecki a1753d5c29 xen/netfront: destroy queues before real_num_tx_queues is zeroed
commit dcf4ff7a48 upstream.

xennet_destroy_queues() relies on info->netdev->real_num_tx_queues to
delete queues. Since d7dac08341
("net-sysfs: update the queue counts in the unregistration path"),
unregister_netdev() indirectly sets real_num_tx_queues to 0. Those two
facts together means, that xennet_destroy_queues() called from
xennet_remove() cannot do its job, because it's called after
unregister_netdev(). This results in kfree-ing queues that are still
linked in napi, which ultimately crashes:

    BUG: kernel NULL pointer dereference, address: 0000000000000000
    #PF: supervisor read access in kernel mode
    #PF: error_code(0x0000) - not-present page
    PGD 0 P4D 0
    Oops: 0000 [#1] PREEMPT SMP PTI
    CPU: 1 PID: 52 Comm: xenwatch Tainted: G        W         5.16.10-1.32.fc32.qubes.x86_64+ #226
    RIP: 0010:free_netdev+0xa3/0x1a0
    Code: ff 48 89 df e8 2e e9 00 00 48 8b 43 50 48 8b 08 48 8d b8 a0 fe ff ff 48 8d a9 a0 fe ff ff 49 39 c4 75 26 eb 47 e8 ed c1 66 ff <48> 8b 85 60 01 00 00 48 8d 95 60 01 00 00 48 89 ef 48 2d 60 01 00
    RSP: 0000:ffffc90000bcfd00 EFLAGS: 00010286
    RAX: 0000000000000000 RBX: ffff88800edad000 RCX: 0000000000000000
    RDX: 0000000000000001 RSI: ffffc90000bcfc30 RDI: 00000000ffffffff
    RBP: fffffffffffffea0 R08: 0000000000000000 R09: 0000000000000000
    R10: 0000000000000000 R11: 0000000000000001 R12: ffff88800edad050
    R13: ffff8880065f8f88 R14: 0000000000000000 R15: ffff8880066c6680
    FS:  0000000000000000(0000) GS:ffff8880f3300000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000000000 CR3: 00000000e998c006 CR4: 00000000003706e0
    Call Trace:
     <TASK>
     xennet_remove+0x13d/0x300 [xen_netfront]
     xenbus_dev_remove+0x6d/0xf0
     __device_release_driver+0x17a/0x240
     device_release_driver+0x24/0x30
     bus_remove_device+0xd8/0x140
     device_del+0x18b/0x410
     ? _raw_spin_unlock+0x16/0x30
     ? klist_iter_exit+0x14/0x20
     ? xenbus_dev_request_and_reply+0x80/0x80
     device_unregister+0x13/0x60
     xenbus_dev_changed+0x18e/0x1f0
     xenwatch_thread+0xc0/0x1a0
     ? do_wait_intr_irq+0xa0/0xa0
     kthread+0x16b/0x190
     ? set_kthread_struct+0x40/0x40
     ret_from_fork+0x22/0x30
     </TASK>

Fix this by calling xennet_destroy_queues() from xennet_uninit(),
when real_num_tx_queues is still available. This ensures that queues are
destroyed when real_num_tx_queues is set to 0, regardless of how
unregister_netdev() was called.

Originally reported at
https://github.com/QubesOS/qubes-issues/issues/7257

Fixes: d7dac08341 ("net-sysfs: update the queue counts in the unregistration path")
Cc: stable@vger.kernel.org
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-08 19:09:31 +01:00
arch riscv: Fix config KASAN && DEBUG_VIRTUAL 2022-03-08 19:09:31 +01:00
block block/wbt: fix negative inflight counter when remove scsi device 2022-02-23 12:01:04 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:50:29 +02:00
crypto crypto: api - Move cryptomgr soft dependency into algapi 2022-02-11 09:09:03 +01:00
Documentation tracing: Add ustring operation to filtering string pointers 2022-03-08 19:09:31 +01:00
drivers xen/netfront: destroy queues before real_num_tx_queues is zeroed 2022-03-08 19:09:31 +01:00
fs exfat: fix i_blocks for files truncated over 4 GiB 2022-03-08 19:09:30 +01:00
include net: Force inlining of checksum functions in net/checksum.h 2022-03-02 11:42:50 +01:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-01-05 12:40:34 +01:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:19:10 +01:00
kernel tracing: Add ustring operation to filtering string pointers 2022-03-08 19:09:31 +01:00
lib lib/iov_iter: initialize "flags" in new pipe_buffer 2022-02-23 12:01:06 +01:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm memblock: use kfree() to release kmalloced memblock regions 2022-03-02 11:42:57 +01:00
net tipc: fix a bit overflow in tipc_crypto_key_rcv() 2022-03-08 19:09:29 +01:00
samples ftrace/samples: Add missing prototypes direct functions 2022-01-11 15:25:00 +01:00
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:01:07 +01:00
security ima: Do not print policy rule with inactive LSM labels 2022-02-16 12:54:16 +01:00
sound ASoC: ops: Shift tested values in snd_soc_put_volsw() by +min 2022-03-08 19:09:31 +01:00
tools selftests/seccomp: Fix seccomp failure by adding missing headers 2022-03-08 19:09:29 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:25:48 +01:00
virt KVM: eventfd: Fix false positive RCU usage warning 2022-02-16 12:54:20 +01:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: adjust GCC PLUGINS after gcc-plugin.sh removal 2021-12-14 11:32:46 +01:00
Makefile Linux 5.10.103 2022-03-02 11:42:57 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.