From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() 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 Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- Documentation/networking/alias.rst | 49 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 Documentation/networking/alias.rst (limited to 'Documentation/networking/alias.rst') diff --git a/Documentation/networking/alias.rst b/Documentation/networking/alias.rst new file mode 100644 index 000000000..af7c5ee92 --- /dev/null +++ b/Documentation/networking/alias.rst @@ -0,0 +1,49 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========== +IP-Aliasing +=========== + +IP-aliases are an obsolete way to manage multiple IP-addresses/masks +per interface. Newer tools such as iproute2 support multiple +address/prefixes per interface, but aliases are still supported +for backwards compatibility. + +An alias is formed by adding a colon and a string when running ifconfig. +This string is usually numeric, but this is not a must. + + +Alias creation +============== + +Alias creation is done by 'magic' interface naming: eg. to create a +200.1.1.1 alias for eth0 ... +:: + + # ifconfig eth0:0 200.1.1.1 etc,etc.... + ~~ -> request alias #0 creation (if not yet exists) for eth0 + +The corresponding route is also set up by this command. Please note: +The route always points to the base interface. + + +Alias deletion +============== + +The alias is removed by shutting the alias down:: + + # ifconfig eth0:0 down + ~~~~~~~~~~ -> will delete alias + + +Alias (re-)configuring +====================== + +Aliases are not real devices, but programs should be able to configure +and refer to them as usual (ifconfig, route, etc). + + +Relationship with main device +============================= + +If the base device is shut down the added aliases will be deleted too. -- cgit v1.3.1