diff options
| author | William A. Kennington III <wak@google.com> | 2021-04-07 02:55:27 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-03 08:22:06 +0200 |
| commit | 62bb2c7f2411a0045c24831f11ecacfc35610815 (patch) | |
| tree | e1b7f422bc0a287f263b794d3388446284cc1862 /drivers/spi | |
| parent | 200dbfcad8011e50c3cec269ed7b980836eeb1fa (diff) | |
spi: Fix use-after-free with devm_spi_alloc_*
commit 794aaf01444d4e765e2b067cba01cc69c1c68ed9 upstream.
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>
[lukas: backport to v4.4.270]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index e85feee750e3..f743b95d5171 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1762,6 +1762,7 @@ struct spi_master *devm_spi_alloc_master(struct device *dev, unsigned int size) master = spi_alloc_master(dev, size); if (master) { + master->devm_allocated = true; *ptr = master; devres_add(dev, ptr); } else { @@ -1951,11 +1952,6 @@ int devm_spi_register_master(struct device *dev, struct spi_master *master) } EXPORT_SYMBOL_GPL(devm_spi_register_master); -static int devm_spi_match_master(struct device *dev, void *res, void *master) -{ - return *(struct spi_master **)res == master; -} - static int __unregister(struct device *dev, void *null) { spi_unregister_device(to_spi_device(dev)); @@ -1994,8 +1990,7 @@ void spi_unregister_master(struct spi_master *master) /* Release the last reference on the master if its driver * has not yet been converted to devm_spi_alloc_master(). */ - if (!devres_find(master->dev.parent, devm_spi_release_master, - devm_spi_match_master, master)) + if (!master->devm_allocated) put_device(&master->dev); if (IS_ENABLED(CONFIG_SPI_DYNAMIC)) |