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| author | William A. Kennington III <wak@google.com> | 2021-04-07 02:55:27 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-14 09:50:16 +0200 |
| commit | c7fabe372a9031acd00498bc718ce27c253abfd1 (patch) | |
| tree | ca0b54fe6c30173f58dbbb2325eb735cc230a11b | |
| parent | 1de36911689c192aa1c20682102ceb956b5372c0 (diff) | |
| download | kernel_replicant_linux-c7fabe372a9031acd00498bc718ce27c253abfd1.tar.gz kernel_replicant_linux-c7fabe372a9031acd00498bc718ce27c253abfd1.tar.bz2 kernel_replicant_linux-c7fabe372a9031acd00498bc718ce27c253abfd1.zip | |
spi: Fix use-after-free with devm_spi_alloc_*
[ Upstream commit 794aaf01444d4e765e2b067cba01cc69c1c68ed9 ]
We can't rely on the contents of the devres list during
spi_unregister_controller(), as the list is already torn down at the
time we perform devres_find() for devm_spi_release_controller. This
causes devices registered with devm_spi_alloc_{master,slave}() to be
mistakenly identified as legacy, non-devm managed devices and have their
reference counters decremented below 0.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 660 at lib/refcount.c:28 refcount_warn_saturate+0x108/0x174
[<b0396f04>] (refcount_warn_saturate) from [<b03c56a4>] (kobject_put+0x90/0x98)
[<b03c5614>] (kobject_put) from [<b0447b4c>] (put_device+0x20/0x24)
r4:b6700140
[<b0447b2c>] (put_device) from [<b07515e8>] (devm_spi_release_controller+0x3c/0x40)
[<b07515ac>] (devm_spi_release_controller) from [<b045343c>] (release_nodes+0x84/0xc4)
r5:b6700180 r4:b6700100
[<b04533b8>] (release_nodes) from [<b0454160>] (devres_release_all+0x5c/0x60)
r8:b1638c54 r7:b117ad94 r6:b1638c10 r5:b117ad94 r4:b163dc10
[<b0454104>] (devres_release_all) from [<b044e41c>] (__device_release_driver+0x144/0x1ec)
r5:b117ad94 r4:b163dc10
[<b044e2d8>] (__device_release_driver) from [<b044f70c>] (device_driver_detach+0x84/0xa0)
r9:00000000 r8:00000000 r7:b117ad94 r6:b163dc54 r5:b1638c10 r4:b163dc10
[<b044f688>] (device_driver_detach) from [<b044d274>] (unbind_store+0xe4/0xf8)
Instead, determine the devm allocation state as a flag on the
controller which is guaranteed to be stable during cleanup.
Fixes: 5e844cc37a5c ("spi: Introduce device-managed SPI controller allocation")
Signed-off-by: William A. Kennington III <wak@google.com>
Link: https://lore.kernel.org/r/20210407095527.2771582-1-wak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/spi/spi.c | 9 | ||||
| -rw-r--r-- | include/linux/spi/spi.h | 3 |
2 files changed, 5 insertions, 7 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 1eee8b3c1b38..419de3d40481 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2480,6 +2480,7 @@ struct spi_controller *__devm_spi_alloc_controller(struct device *dev, ctlr = __spi_alloc_controller(dev, size, slave); if (ctlr) { + ctlr->devm_allocated = true; *ptr = ctlr; devres_add(dev, ptr); } else { @@ -2826,11 +2827,6 @@ int devm_spi_register_controller(struct device *dev, } EXPORT_SYMBOL_GPL(devm_spi_register_controller); -static int devm_spi_match_controller(struct device *dev, void *res, void *ctlr) -{ - return *(struct spi_controller **)res == ctlr; -} - static int __unregister(struct device *dev, void *null) { spi_unregister_device(to_spi_device(dev)); @@ -2877,8 +2873,7 @@ void spi_unregister_controller(struct spi_controller *ctlr) /* Release the last reference on the controller if its driver * has not yet been converted to devm_spi_alloc_master/slave(). */ - if (!devres_find(ctlr->dev.parent, devm_spi_release_controller, - devm_spi_match_controller, ctlr)) + if (!ctlr->devm_allocated) put_device(&ctlr->dev); /* free bus id */ diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index b390fdac1587..2d906b9c1499 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -511,6 +511,9 @@ struct spi_controller { #define SPI_MASTER_GPIO_SS BIT(5) /* GPIO CS must select slave */ + /* flag indicating this is a non-devres managed controller */ + bool devm_allocated; + /* flag indicating this is an SPI slave controller */ bool slave; |