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 --- arch/xtensa/Kconfig.debug | 48 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 arch/xtensa/Kconfig.debug (limited to 'arch/xtensa/Kconfig.debug') diff --git a/arch/xtensa/Kconfig.debug b/arch/xtensa/Kconfig.debug new file mode 100644 index 000000000..e84172a77 --- /dev/null +++ b/arch/xtensa/Kconfig.debug @@ -0,0 +1,48 @@ +# SPDX-License-Identifier: GPL-2.0 + +config DEBUG_TLB_SANITY + bool "Debug TLB sanity" + depends on DEBUG_KERNEL && MMU + help + Enable this to turn on TLB sanity check on each entry to userspace. + This check can spot missing TLB invalidation/wrong PTE permissions/ + premature page freeing. + + If unsure, say N. + +config LD_NO_RELAX + bool "Disable linker relaxation" + default y + help + Enable this function to disable link-time optimizations. + The default linker behavior is to combine identical literal + values to reduce code size and remove unnecessary overhead from + assembler-generated 'longcall' sequences. + Enabling this option improves the link time but increases the + code size, and possibly execution time. + +config S32C1I_SELFTEST + bool "Perform S32C1I instruction self-test at boot" + default y + help + Enable this option to test S32C1I instruction behavior at boot. + Correct operation of this instruction requires some cooperation from hardware + external to the processor (such as bus bridge, bus fabric, or memory controller). + It is easy to make wrong hardware configuration, this test should catch it early. + + Say 'N' on stable hardware. + +config PRINT_STACK_DEPTH + int "Stack depth to print" if DEBUG_KERNEL + default 64 + help + This option allows you to set the stack depth that the kernel + prints in stack traces. + +config PRINT_USER_CODE_ON_UNHANDLED_EXCEPTION + bool "Dump user code around unhandled exception address" + help + Enable this option to display user code around PC of the unhandled + exception (starting at address aligned on 16 byte boundary). + This may simplify finding faulting code in the absence of other + debug facilities. -- cgit v1.3.1