[SRU][J:linux-bluefield][PATCH 0/1] genetlink: fix single op policy dump when do is present

[William Tu]

intro
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Our internal test triggers a kernel crash dump below
[ 888.690348] Sun Mar 24 23:51:59 2024: DriVerTest - Start Test
 [ 888.691834] ----------------------------------------------------------------------------------------------------
 [ 888.983912] mlx5_core 0000:08:00.1
eth3: Link up
 [ 888.987644] IPv6: ADDRCONF(NETDEV_CHANGE): eth3: link becomes ready
 [ 889.336577] mlx5_core 0000:08:00.0 eth2: Link up
 [ 894.635836] Sun Mar 24 11:52:04 PM IST 2024 - DriVerTest Debug Heartbeat
 [ 940.431644] general protection fault, probably for non-canonical address 0x8002001400000000: 0000 [#1] SMP NOPTI
 [ 940.432866] CPU: 7 PID: 94305 Comm: ethtool Tainted: G OE 5.15.0-1039.17.g0d63875-bluefield #1
 [ 940.433970] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 [ 940.435220] RIP: 0010:netlink_policy_dump_add_policy+0x95/0x160

fix
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Need to cherry-pick the following patch

commit c1b05105573b2cd5845921eb0d2caa26e2144a34
Author: Jakub Kicinski <kuba at kernel.org>
Date: Wed Nov 9 10:32:54 2022 -0800

    genetlink: fix single op policy dump when do is present

    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

Jakub Kicinski (1):
  genetlink: fix single op policy dump when do is present

 net/netlink/genetlink.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

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2.37.1 (Apple Git-137.1)