diff options
author | Mark Hasemeyer <markhas@chromium.org> | 2023-11-08 00:47:43 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-11-28 20:19:55 +0300 |
commit | 96474ea47dc67b0704392d59192b233c8197db0e (patch) | |
tree | 75615b86ecc142b05d88c309a5a1494ea7732fcd /drivers/spi | |
parent | 792473a4e0eb872443ff30bc96f2b7cd0d878619 (diff) | |
download | linux-96474ea47dc67b0704392d59192b233c8197db0e.tar.xz |
spi: Fix null dereference on suspend
commit bef4a48f4ef798c4feddf045d49e53c8a97d5e37 upstream.
A race condition exists where a synchronous (noqueue) transfer can be
active during a system suspend. This can cause a null pointer
dereference exception to occur when the system resumes.
Example order of events leading to the exception:
1. spi_sync() calls __spi_transfer_message_noqueue() which sets
ctlr->cur_msg
2. Spi transfer begins via spi_transfer_one_message()
3. System is suspended interrupting the transfer context
4. System is resumed
6. spi_controller_resume() calls spi_start_queue() which resets cur_msg
to NULL
7. Spi transfer context resumes and spi_finalize_current_message() is
called which dereferences cur_msg (which is now NULL)
Wait for synchronous transfers to complete before suspending by
acquiring the bus mutex and setting/checking a suspend flag.
Signed-off-by: Mark Hasemeyer <markhas@chromium.org>
Link: https://lore.kernel.org/r/20231107144743.v1.1.I7987f05f61901f567f7661763646cb7d7919b528@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r-- | drivers/spi/spi.c | 56 |
1 files changed, 39 insertions, 17 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 8d6304cb061e..399e81d37b3b 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -3323,33 +3323,52 @@ void spi_unregister_controller(struct spi_controller *ctlr) } EXPORT_SYMBOL_GPL(spi_unregister_controller); +static inline int __spi_check_suspended(const struct spi_controller *ctlr) +{ + return ctlr->flags & SPI_CONTROLLER_SUSPENDED ? -ESHUTDOWN : 0; +} + +static inline void __spi_mark_suspended(struct spi_controller *ctlr) +{ + mutex_lock(&ctlr->bus_lock_mutex); + ctlr->flags |= SPI_CONTROLLER_SUSPENDED; + mutex_unlock(&ctlr->bus_lock_mutex); +} + +static inline void __spi_mark_resumed(struct spi_controller *ctlr) +{ + mutex_lock(&ctlr->bus_lock_mutex); + ctlr->flags &= ~SPI_CONTROLLER_SUSPENDED; + mutex_unlock(&ctlr->bus_lock_mutex); +} + int spi_controller_suspend(struct spi_controller *ctlr) { - int ret; + int ret = 0; /* Basically no-ops for non-queued controllers */ - if (!ctlr->queued) - return 0; - - ret = spi_stop_queue(ctlr); - if (ret) - dev_err(&ctlr->dev, "queue stop failed\n"); + if (ctlr->queued) { + ret = spi_stop_queue(ctlr); + if (ret) + dev_err(&ctlr->dev, "queue stop failed\n"); + } + __spi_mark_suspended(ctlr); return ret; } EXPORT_SYMBOL_GPL(spi_controller_suspend); int spi_controller_resume(struct spi_controller *ctlr) { - int ret; - - if (!ctlr->queued) - return 0; + int ret = 0; - ret = spi_start_queue(ctlr); - if (ret) - dev_err(&ctlr->dev, "queue restart failed\n"); + __spi_mark_resumed(ctlr); + if (ctlr->queued) { + ret = spi_start_queue(ctlr); + if (ret) + dev_err(&ctlr->dev, "queue restart failed\n"); + } return ret; } EXPORT_SYMBOL_GPL(spi_controller_resume); @@ -4153,8 +4172,7 @@ static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct s ctlr->cur_msg = msg; ret = __spi_pump_transfer_message(ctlr, msg, was_busy); if (ret) - goto out; - + dev_err(&ctlr->dev, "noqueue transfer failed\n"); ctlr->cur_msg = NULL; ctlr->fallback = false; @@ -4170,7 +4188,6 @@ static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct s spi_idle_runtime_pm(ctlr); } -out: mutex_unlock(&ctlr->io_mutex); } @@ -4193,6 +4210,11 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message) int status; struct spi_controller *ctlr = spi->controller; + if (__spi_check_suspended(ctlr)) { + dev_warn_once(&spi->dev, "Attempted to sync while suspend\n"); + return -ESHUTDOWN; + } + status = __spi_validate(spi, message); if (status != 0) return status; |