From: Michael Walle michael@walle.cc
mainline inclusion from mainline-v5.16-rc2 commit 6c53b45c71b4920b5e62f0ea8079a1da382b9434 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RBZI CVE: CVE-2021-47469
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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 Signed-off-by: Zeng Heng zengheng4@huawei.com --- drivers/spi/spi.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index d5bc995de16b..d510b9ca798f 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2888,12 +2888,6 @@ 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) @@ -2902,6 +2896,12 @@ 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);