From: Simon Horman <horms@kernel•org>
To: Petr Tesarik <petr@tesarici•cz>
Cc: "David S. Miller" <davem@davemloft•net>,
Eric Dumazet <edumazet@google•com>,
open list <netdev@vger•kernel.org>,
Linux regressions mailing list <regressions@lists•linux.dev>,
open list <linux-kernel@vger•kernel.org>,
"Linux regression tracking (Thorsten Leemhuis)"
<regressions@leemhuis•info>
Subject: Re: [PATCH net] u64_stats: fix u64_stats_init() for lockdep when used repeatedly in one file
Date: Fri, 5 Apr 2024 20:51:17 +0100 [thread overview]
Message-ID: <20240405195117.GV26556@kernel.org> (raw)
In-Reply-To: <20240404075740.30682-1-petr@tesarici.cz>
On Thu, Apr 04, 2024 at 09:57:40AM +0200, Petr Tesarik wrote:
> Fix bogus lockdep warnings if multiple u64_stats_sync variables are
> initialized in the same file.
>
> With CONFIG_LOCKDEP, seqcount_init() is a macro which declares:
>
> static struct lock_class_key __key;
>
> Since u64_stats_init() is a function (albeit an inline one), all calls
> within the same file end up using the same instance, effectively treating
> them all as a single lock-class.
>
> Fixes: 9464ca650008 ("net: make u64_stats_init() a function")
> Closes: https://lore.kernel.org/netdev/ea1567d9-ce66-45e6-8168-ac40a47d1821@roeck-us.net/
> Signed-off-by: Petr Tesarik <petr@tesarici•cz>
Reviewed-by: Simon Horman <horms@kernel•org>
Interesting bug. I'm wondering if you also looked over other users of
u64_stats_init() to see if any of them can result in unexpected aliasing of
lock keys too.
...
next prev parent reply other threads:[~2024-04-05 19:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-04 7:57 [PATCH net] u64_stats: fix u64_stats_init() for lockdep when used repeatedly in one file Petr Tesarik
2024-04-05 19:51 ` Simon Horman [this message]
2024-04-06 8:12 ` Petr Tesařík
2024-04-05 21:08 ` Eric Dumazet
2024-04-06 7:44 ` Petr Tesařík
2024-04-06 6:10 ` patchwork-bot+netdevbpf
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