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e9942bfe49
Unloading the ice driver while switchdev port representors are added to
a bridge can lead to kernel panic. Reproducer:
modprobe ice
devlink dev eswitch set $PF1_PCI mode switchdev
ip link add $BR type bridge
ip link set $BR up
echo 2 > /sys/class/net/$PF1/device/sriov_numvfs
sleep 2
ip link set $PF1 master $BR
ip link set $VF1_PR master $BR
ip link set $VF2_PR master $BR
ip link set $PF1 up
ip link set $VF1_PR up
ip link set $VF2_PR up
ip link set $VF1 up
rmmod irdma ice
When unloading the driver, ice_eswitch_detach() is eventually called as
part of VF freeing. First, it removes a port representor from xarray,
then unregister_netdev() is called (via repr->ops.rem()), finally
representor is deallocated. The problem comes from the bridge doing its
own deinit at the same time. unregister_netdev() triggers a notifier
chain, resulting in ice_eswitch_br_port_deinit() being called. It should
set repr->br_port = NULL, but this does not happen since repr has
already been removed from xarray and is not found. Regardless, it
finishes up deallocating br_port. At this point, repr is still not freed
and an fdb event can happen, in which ice_eswitch_br_fdb_event_work()
takes repr->br_port and tries to use it, which causes a panic (use after
free).
Note that this only happens with 2 or more port representors added to
the bridge, since with only one representor port, the bridge deinit is
slightly different (ice_eswitch_br_port_deinit() is called via
ice_eswitch_br_ports_flush(), not ice_eswitch_br_port_unlink()).
Trace:
Oops: general protection fault, probably for non-canonical address 0xf129010fd1a93284: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: maybe wild-memory-access in range [0x8948287e8d499420-0x8948287e8d499427]
(...)
Workqueue: ice_bridge_wq ice_eswitch_br_fdb_event_work [ice]
RIP: 0010:__rht_bucket_nested+0xb4/0x180
(...)
Call Trace:
(...)
ice_eswitch_br_fdb_find+0x3fa/0x550 [ice]
? __pfx_ice_eswitch_br_fdb_find+0x10/0x10 [ice]
ice_eswitch_br_fdb_event_work+0x2de/0x1e60 [ice]
? __schedule+0xf60/0x5210
? mutex_lock+0x91/0xe0
? __pfx_ice_eswitch_br_fdb_event_work+0x10/0x10 [ice]
? ice_eswitch_br_update_work+0x1f4/0x310 [ice]
(...)
A workaround is available: brctl setageing $BR 0, which stops the bridge
from adding fdb entries altogether.
Change the order of operations in ice_eswitch_detach(): move the call to
unregister_netdev() before removing repr from xarray. This way
repr->br_port will be correctly set to NULL in
ice_eswitch_br_port_deinit(), preventing a panic.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 reStructuredText 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.