From: Jakub Kicinski <kuba@kernel.org>
To: Antoine Tenart <atenart@kernel.org>
Cc: davem@davemloft.net, pabeni@redhat.com, edumazet@google.com,
netdev@vger.kernel.org, gregkh@linuxfoundation.org,
mhocko@suse.com, stephen@networkplumber.org
Subject: Re: [RFC PATCH net-next 1/4] net-sysfs: remove rtnl_trylock from device attributes
Date: Thu, 2 Jan 2025 14:36:47 -0800 [thread overview]
Message-ID: <20250102143647.7963cbfd@kernel.org> (raw)
In-Reply-To: <20231018154804.420823-2-atenart@kernel.org>
On Wed, 18 Oct 2023 17:47:43 +0200 Antoine Tenart wrote:
> We have an ABBA deadlock between net device unregistration and sysfs
> files being accessed[1][2]. To prevent this from happening all paths
> taking the rtnl lock after the sysfs one (actually kn->active refcount)
> use rtnl_trylock and return early (using restart_syscall)[3] which can
> make syscalls to spin for a long time when there is contention on the
> rtnl lock[4].
Hi Antoine!
I was looking at the sysfs locking, and ended up going down a very
similar path. Luckily lore search for sysfs_break_active_protection()
surfaced this thread so I can save myself some duplicated work :)
Is there any particular reason why you haven't pursued this solution
further? I think it should work.
My version, FWIW:
https://github.com/kuba-moo/linux/commit/2724bb7275496a254b001fe06fe20ccc5addc9d2
next prev parent reply other threads:[~2025-01-02 22:36 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-18 15:47 [RFC PATCH net-next 0/4] net-sysfs: remove rtnl_trylock/restart_syscall use Antoine Tenart
2023-10-18 15:47 ` [RFC PATCH net-next 1/4] net-sysfs: remove rtnl_trylock from device attributes Antoine Tenart
2023-10-18 16:49 ` Greg KH
2023-10-19 8:13 ` Antoine Tenart
2023-10-19 15:37 ` Greg KH
2023-10-18 18:13 ` Stephen Hemminger
2023-10-19 7:48 ` Antoine Tenart
2025-01-02 22:36 ` Jakub Kicinski [this message]
2025-01-03 8:41 ` Eric Dumazet
2025-01-07 16:30 ` Antoine Tenart
2025-01-07 17:06 ` Jakub Kicinski
2025-01-16 13:36 ` Antoine Tenart
2025-01-16 23:42 ` Jakub Kicinski
2025-01-16 23:43 ` Jakub Kicinski
2025-01-17 8:26 ` Antoine Tenart
2023-10-18 15:47 ` [RFC PATCH net-next 2/4] net-sysfs: move queue attribute groups outside the default groups Antoine Tenart
2023-10-18 15:47 ` [RFC PATCH net-next 3/4] net-sysfs: prevent uncleared queues from being re-added Antoine Tenart
2023-10-18 15:47 ` [RFC PATCH net-next 4/4] net-sysfs: remove rtnl_trylock from queue attributes Antoine Tenart
2023-10-18 15:57 ` [RFC PATCH net-next 0/4] net-sysfs: remove rtnl_trylock/restart_syscall use Stephen Hemminger
2023-10-18 16:34 ` Antoine Tenart
2023-10-18 18:15 ` Stephen Hemminger
2023-10-19 7:47 ` Antoine Tenart
2023-10-19 14:54 ` Stephen Hemminger
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