842a40c727
[ Upstream commit a699781c79ecf6cfe67fb00a0331b4088c7c8466 ]
A sysfs reader can race with a device reset or removal, attempting to
read device state when the device is not actually present. eg:
[exception RIP: qed_get_current_link+17]
#8 [ffffb9e4f2907c48] qede_get_link_ksettings at ffffffffc07a994a [qede]
#9 [ffffb9e4f2907cd8] __rh_call_get_link_ksettings at ffffffff992b01a3
#10 [ffffb9e4f2907d38] __ethtool_get_link_ksettings at ffffffff992b04e4
#11 [ffffb9e4f2907d90] duplex_show at ffffffff99260300
#12 [ffffb9e4f2907e38] dev_attr_show at ffffffff9905a01c
#13 [ffffb9e4f2907e50] sysfs_kf_seq_show at ffffffff98e0145b
#14 [ffffb9e4f2907e68] seq_read at ffffffff98d902e3
#15 [ffffb9e4f2907ec8] vfs_read at ffffffff98d657d1
#16 [ffffb9e4f2907f00] ksys_read at ffffffff98d65c3f
#17 [ffffb9e4f2907f38] do_syscall_64 at ffffffff98a052fb
crash> struct net_device.state ffff9a9d21336000
state = 5,
state 5 is __LINK_STATE_START (0b1) and __LINK_STATE_NOCARRIER (0b100).
The device is not present, note lack of __LINK_STATE_PRESENT (0b10).
This is the same sort of panic as observed in commit 4224cfd7fb65
("net-sysfs: add check for netdevice being present to speed_show").
There are many other callers of __ethtool_get_link_ksettings() which
don't have a device presence check.
Move this check into ethtool to protect all callers.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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 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.