Re: [PATCH net-next v3 4/8] selftests/net: Open /proc/thread-self in open_netns()

[Simon Horman <horms@kernel.org>]

On Thu, Aug 15, 2024 at 10:32:29PM +0100, Dmitry Safonov via B4 Relay wrote:
> From: Dmitry Safonov <0x7f454c46@gmail.com>
> 
> It turns to be that open_netns() is called rarely from the child-thread
> and more often from parent-thread. Yet, on initialization of kconfig
> checks, either of threads may reach kconfig_lock mutex first.
> VRF-related checks do create a temprary ksft-check VRF in

nit: temporary

     Flagged by checkpatch.pl --codespell

> an unshare()'d namespace and than setns() back to the original.
> As original was opened from "/proc/self/ns/net", it's valid for
> thread-leader (parent), but it's invalid for the child, resulting
> in the following failure on tests that check has_vrfs() support:
> > # ok 54 TCP-AO required on socket + TCP-MD5 key: prefailed as expected: Key was rejected by service
> > # not ok 55 # error 381[unsigned-md5.c:24] Failed to add a VRF: -17
> > # not ok 56 # error 383[unsigned-md5.c:33] Failed to add a route to VRF: -22: Key was rejected by service
> > not ok 1 selftests: net/tcp_ao: unsigned-md5_ipv6 # exit=1
> 
> Use "/proc/thread-self/ns/net" which is valid for any thread.
> 
> Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>

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