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| author | Shivank Garg <shivankg@amd.com> | 2026-08-22 19:22:05 +0000 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2026-09-09 17:51:44 +0530 |
| commit | e873c74132f0c5f1452816cd9bb26208f0bba1e1 (patch) | |
| tree | cc1ce1567f5b982359331863ebd9da38741f8d2e /Documentation/ABI/testing/sysfs-devices-mapping | |
| download | linux-stable-e873c74132f0c5f1452816cd9bb26208f0bba1e1.tar.gz linux-stable-e873c74132f0c5f1452816cd9bb26208f0bba1e1.zip | |
dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel()grafted
When dma_device_put() drops the last reference on chan->device->ref,
dma_device_release() runs and may free the dma_device along with its
channels.
dma_chan_put() then still reads chan->device->owner via
dma_chan_to_owner() for the trailing module_put(). KASAN catches it:
slab-use-after-free in dma_chan_put+0x3e6/0x4c0
Read of size 8 by task insmod/6319
Freed by task 6319:
kfree+0x225/0x470
dma_chan_put+0x395/0x4c0
dmaengine_put+0xf8/0x160
Cache the module owner in dma_chan_put() before the put so the trailing
module_put() does not need chan->device.
Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct")
Suggested-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-devices-mapping')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-mapping | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-mapping b/Documentation/ABI/testing/sysfs-devices-mapping new file mode 100644 index 000000000..2eee1446a --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-mapping @@ -0,0 +1,62 @@ +What: /sys/devices/uncore_iio_x/dieX +Date: February 2020 +Contact: Alexander Antonov <alexander.antonov@linux.intel.com> +Description: + Each IIO stack (PCIe root port) has its own IIO PMON block, so + each dieX file (where X is die number) holds "Segment:Root Bus" + for PCIe root port, which can be monitored by that IIO PMON + block. + For example, on 4-die Xeon platform with up to 6 IIO stacks per + die and, therefore, 6 IIO PMON blocks per die, the mapping of + IIO PMON block 0 exposes as the following:: + + $ ls /sys/devices/uncore_iio_0/die* + -r--r--r-- /sys/devices/uncore_iio_0/die0 + -r--r--r-- /sys/devices/uncore_iio_0/die1 + -r--r--r-- /sys/devices/uncore_iio_0/die2 + -r--r--r-- /sys/devices/uncore_iio_0/die3 + + $ tail /sys/devices/uncore_iio_0/die* + ==> /sys/devices/uncore_iio_0/die0 <== + 0000:00 + ==> /sys/devices/uncore_iio_0/die1 <== + 0000:40 + ==> /sys/devices/uncore_iio_0/die2 <== + 0000:80 + ==> /sys/devices/uncore_iio_0/die3 <== + 0000:c0 + + Which means:: + + IIO PMU 0 on die 0 belongs to PCI RP on bus 0x00, domain 0x0000 + IIO PMU 0 on die 1 belongs to PCI RP on bus 0x40, domain 0x0000 + IIO PMU 0 on die 2 belongs to PCI RP on bus 0x80, domain 0x0000 + IIO PMU 0 on die 3 belongs to PCI RP on bus 0xc0, domain 0x0000 + +What: /sys/devices/uncore_upi_x/dieX +Date: March 2022 +Contact: Alexander Antonov <alexander.antonov@linux.intel.com> +Description: + Each /sys/devices/uncore_upi_X/dieY file holds "upi_Z,die_W" + value that means UPI link number X on die Y is connected to UPI + link Z on die W and this link between sockets can be monitored + by UPI PMON block. + For example, 4-die Sapphire Rapids platform has the following + UPI 0 topology:: + + # tail /sys/devices/uncore_upi_0/die* + ==> /sys/devices/uncore_upi_0/die0 <== + upi_1,die_1 + ==> /sys/devices/uncore_upi_0/die1 <== + upi_0,die_3 + ==> /sys/devices/uncore_upi_0/die2 <== + upi_1,die_3 + ==> /sys/devices/uncore_upi_0/die3 <== + upi_0,die_1 + + Which means:: + + UPI link 0 on die 0 is connected to UPI link 1 on die 1 + UPI link 0 on die 1 is connected to UPI link 0 on die 3 + UPI link 0 on die 2 is connected to UPI link 1 on die 3 + UPI link 0 on die 3 is connected to UPI link 0 on die 1
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