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c1b0510557
Jonathan reports crashes when running net-next in Meta's fleet.
Stats collection uses ethtool -I which does a per-op policy dump
to check if stats are supported. We don't initialize the dumpit
information if doit succeeds due to evaluation short-circuiting.
The crash may look like this:
BUG: kernel NULL pointer dereference, address: 0000000000000cc0
RIP: 0010:netlink_policy_dump_add_policy+0x174/0x2a0
ctrl_dumppolicy_start+0x19f/0x2f0
genl_start+0xe7/0x140
Or we may trigger a warning:
WARNING: CPU: 1 PID: 785 at net/netlink/policy.c:87 netlink_policy_dump_get_policy_idx+0x79/0x80
RIP: 0010:netlink_policy_dump_get_policy_idx+0x79/0x80
ctrl_dumppolicy_put_op+0x214/0x360
depending on what garbage we pick up from the stack.
Reported-by: Jonathan Lemon <bsd@meta.com>
Fixes: 26588edbef ("genetlink: support split policies in ctrl_dumppolicy_put_op()")
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20221109183254.554051-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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.