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authorMichael Walle <michael@walle.cc>2021-11-11 11:37:13 +0300
committerMark Brown <broonie@kernel.org>2021-11-12 21:18:03 +0300
commit6c53b45c71b4920b5e62f0ea8079a1da382b9434 (patch)
tree88fa899b8a1afdf75f87aa0123590884049a571f /drivers/spi
parent6532582c353f4c83e3ccdd7255020ab852b90b0b (diff)
downloadlinux-6c53b45c71b4920b5e62f0ea8079a1da382b9434.tar.xz
spi: fix use-after-free of the add_lock mutex
Commit 6098475d4cb4 ("spi: Fix deadlock when adding SPI controllers on SPI buses") introduced a per-controller mutex. But mutex_unlock() of said lock is called after the controller is already freed: spi_unregister_controller(ctlr) -> put_device(&ctlr->dev) -> spi_controller_release(dev) -> mutex_unlock(&ctrl->add_lock) Move the put_device() after the mutex_unlock(). Fixes: 6098475d4cb4 ("spi: Fix deadlock when adding SPI controllers on SPI buses") Signed-off-by: Michael Walle <michael@walle.cc> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org # v5.15 Link: https://lore.kernel.org/r/20211111083713.3335171-1-michael@walle.cc Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 72826bdab270..a2988aed984c 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3058,12 +3058,6 @@ void spi_unregister_controller(struct spi_controller *ctlr)
device_del(&ctlr->dev);
- /* Release the last reference on the controller if its driver
- * has not yet been converted to devm_spi_alloc_master/slave().
- */
- if (!ctlr->devm_allocated)
- put_device(&ctlr->dev);
-
/* free bus id */
mutex_lock(&board_lock);
if (found == ctlr)
@@ -3072,6 +3066,12 @@ void spi_unregister_controller(struct spi_controller *ctlr)
if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_unlock(&ctlr->add_lock);
+
+ /* Release the last reference on the controller if its driver
+ * has not yet been converted to devm_spi_alloc_master/slave().
+ */
+ if (!ctlr->devm_allocated)
+ put_device(&ctlr->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);