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/alpha/Kconfig.debug | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 arch/alpha/Kconfig.debug (limited to 'arch/alpha/Kconfig.debug') diff --git a/arch/alpha/Kconfig.debug b/arch/alpha/Kconfig.debug new file mode 100644 index 000000000..f85f4281c --- /dev/null +++ b/arch/alpha/Kconfig.debug @@ -0,0 +1,38 @@ +# SPDX-License-Identifier: GPL-2.0 + +config EARLY_PRINTK + bool + depends on ALPHA_GENERIC || ALPHA_SRM + default y + +config ALPHA_LEGACY_START_ADDRESS + bool "Legacy kernel start address" + depends on ALPHA_GENERIC + default n + help + The 2.4 kernel changed the kernel start address from 0x310000 + to 0x810000 to make room for the Wildfire's larger SRM console. + Recent consoles on Titan and Marvel machines also require the + extra room. + + If you're using aboot 0.7 or later, the bootloader will examine the + ELF headers to determine where to transfer control. Unfortunately, + most older bootloaders -- APB or MILO -- hardcoded the kernel start + address rather than examining the ELF headers, and the result is a + hard lockup. + + Say Y if you have a broken bootloader. Say N if you do not, or if + you wish to run on Wildfire, Titan, or Marvel. + +config ALPHA_LEGACY_START_ADDRESS + bool + depends on !ALPHA_GENERIC && !ALPHA_TITAN && !ALPHA_MARVEL && !ALPHA_WILDFIRE + default y + +config MATHEMU + tristate "Kernel FP software completion" if DEBUG_KERNEL && !SMP + default y if !DEBUG_KERNEL || SMP + help + This option is required for IEEE compliant floating point arithmetic + on the Alpha. The only time you would ever not say Y is to say M in + order to debug the code. Say Y unless you know what you are doing. -- cgit v1.3.1