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bh=g6eyY98qNh4jG6A7wQCkjm6t762hh/aar5NQBQzO22M=; b=N136686bEyKPmCmcMR5kAlo27b1ndWXpdRTgRyICSXoUZmI7Yr7YylgtVEuodLlthQXJhr qmKA7a6kfARv3k7ZnvJpCJALkbZvTFYAsePuUW4PIRCC4ktjmsN+rl6GN23kfAX9hAe7cZ 779AI5VJyCcEF1H6t4m5CXORC+Eomoo55H3SsIDrXbW3TcqWmsGxbcbO6tT5X5NTWkyxqP D3WHfEith74m9s+WJ2iu918bqZYJZ8jtXGbGcOorjDZX2LI45C7WZ8uqX0CJ0W59upAsYD FFta6D/QDkxKESy+k/PNTbU7oT7AW2VC81HXg3nIsOXYEfEMpQ5MODNapmdgPA== ARC-Authentication-Results: i=1; ORIGINATING; auth=pass smtp.auth=pza@pengutronix.de smtp.mailfrom=p.zabel@pengutronix.de ARC-Seal: i=1; s=20260414; d=pengutronix.de; t=1793875250; a=rsa-sha256; cv=none; b=O+4buIupM7BTIjjSz2gB/yIy0JAZCLomW0eVNcD2MYH95G1qghwccriaDNinXQOqsGNeCz SUA5Z/84cERbS9cjJ1UQZqgwG2VFwYn6p9hmtl/ziSvmgrjvOhvojh+fN4QVGMnXUwQW2A k0kvR7kiwg9mGDOLZs8Dh9cEV4TYIOZrP3A1aL2HaxzC3q1mlOgqVJCPlIvngA7lTuhPiM ICs2mLU9MRH9h8zuOEbeEbgSMLGjYcqstNjUDvFxFELM4FGQeBVI2jdIeRW4xmfqh7PX47 +k872iUD6LBWZMHNip4nXyFap2UvOFiostOWry4Nc7thPBlWqFetGR+mgtz//A== Message-ID: <0c103dec7f28167eab0fc12f56f9920b5d4ead6e.camel@pengutronix.de> Subject: Re: [PATCH v2 2/2] reset: Fix circular locking dependency in reset_controller_unregister() From: Philipp Zabel To: Tzung-Bi Shih Cc: Bartosz Golaszewski , linux-kernel@vger.kernel.org Date: Thu, 05 Nov 2026 11:40:50 +0100 In-Reply-To: <20261104162038.48622-3-tzungbi@kernel.org> References: <20261104162038.48622-1-tzungbi@kernel.org> <20261104162038.48622-3-tzungbi@kernel.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2-0+deb13u1 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 On Do, 2026-11-05 at 00:20 +0800, Tzung-Bi Shih wrote: > reset_control_acquire() and reset_control_put_internal() acquire > `rcdev->lock` inside the `rstc->srcu` read-side critical section > (`rstc->srcu` -> `rcdev->lock`). >=20 > However, reset_controller_unregister() holds `rcdev->lock` while calling > synchronize_srcu(&rstc->srcu) (`rcdev->lock` -> `rstc->srcu`), causing a > lockdep circular locking dependency warning and a potential ABBA > deadlock. >=20 > Run synchronize_srcu() outside `rcdev->lock`. >=20 > Fixes: 44a0acb2caca ("reset: protect struct reset_controller_dev with its= own mutex") > Signed-off-by: Tzung-Bi Shih Reviewed-by: Philipp Zabel regards Philipp