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/userspace-api/ELF.rst | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 Documentation/userspace-api/ELF.rst (limited to 'Documentation/userspace-api/ELF.rst') diff --git a/Documentation/userspace-api/ELF.rst b/Documentation/userspace-api/ELF.rst new file mode 100644 index 000000000..ac8aeacd4 --- /dev/null +++ b/Documentation/userspace-api/ELF.rst @@ -0,0 +1,34 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================= +Linux-specific ELF idiosyncrasies +================================= + +Definitions +=========== + +"First" program header is the one with the smallest offset in the file: +e_phoff. + +"Last" program header is the one with the biggest offset in the file: +e_phoff + (e_phnum - 1) * sizeof(Elf_Phdr). + +PT_INTERP +========= + +First PT_INTERP program header is used to locate the filename of ELF +interpreter. Other PT_INTERP headers are ignored (since Linux 2.4.11). + +PT_GNU_STACK +============ + +Last PT_GNU_STACK program header defines userspace stack executability +(since Linux 2.6.6). Other PT_GNU_STACK headers are ignored. + +PT_GNU_PROPERTY +=============== + +ELF interpreter's last PT_GNU_PROPERTY program header is used (since +Linux 5.8). If interpreter doesn't have one, then the last PT_GNU_PROPERTY +program header of an executable is used. Other PT_GNU_PROPERTY headers +are ignored. -- cgit v1.3.1