This is a note to let you know that I've just added the patch titled ARM: 9216/1: Fix MAX_DMA_ADDRESS overflow to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm-9216-1-fix-max_dma_address-overflow.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 327337c62251d9682c6e6a4220ebadb952023c9f Author: Florian Fainelli <f.fainelli@xxxxxxxxx> Date: Tue Jul 19 17:33:21 2022 +0100 ARM: 9216/1: Fix MAX_DMA_ADDRESS overflow [ Upstream commit fb0fd3469ead5b937293c213daa1f589b4b7ce46 ] Commit 26f09e9b3a06 ("mm/memblock: add memblock memory allocation apis") added a check to determine whether arm_dma_zone_size is exceeding the amount of kernel virtual address space available between the upper 4GB virtual address limit and PAGE_OFFSET in order to provide a suitable definition of MAX_DMA_ADDRESS that should fit within the 32-bit virtual address space. The quantity used for comparison was off by a missing trailing 0, leading to MAX_DMA_ADDRESS to be overflowing a 32-bit quantity. This was caught thanks to CONFIG_DEBUG_VIRTUAL on the bcm2711 platform where we define a dma_zone_size of 1GB and we have a PAGE_OFFSET value of 0xc000_0000 (CONFIG_VMSPLIT_3G) leading to MAX_DMA_ADDRESS being 0x1_0000_0000 which overflows the unsigned long type used throughout __pa() and then __virt_addr_valid(). Because the virtual address passed to __virt_addr_valid() would now be 0, the function would loudly warn and flood the kernel log, thus making the platform unable to boot properly. Fixes: 26f09e9b3a06 ("mm/memblock: add memblock memory allocation apis") Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/arm/include/asm/dma.h b/arch/arm/include/asm/dma.h index a81dda65c576..45180a2cc47c 100644 --- a/arch/arm/include/asm/dma.h +++ b/arch/arm/include/asm/dma.h @@ -10,7 +10,7 @@ #else #define MAX_DMA_ADDRESS ({ \ extern phys_addr_t arm_dma_zone_size; \ - arm_dma_zone_size && arm_dma_zone_size < (0x10000000 - PAGE_OFFSET) ? \ + arm_dma_zone_size && arm_dma_zone_size < (0x100000000ULL - PAGE_OFFSET) ? \ (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; }) #endif