diff options
| author | Michael Walle <michael@walle.cc> | 2021-11-11 11:37:13 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2021-11-12 21:18:03 +0300 |
| commit | 6c53b45c71b4920b5e62f0ea8079a1da382b9434 (patch) | |
| tree | 88fa899b8a1afdf75f87aa0123590884049a571f /drivers/spi | |
| parent | 6532582c353f4c83e3ccdd7255020ab852b90b0b (diff) | |
| download | linux-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.c | 12 |
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); |