From f295ec6b88a11e90ed92b00b9451114442e29586 Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Tue, 17 Sep 2024 17:03:28 +0200 Subject: [PATCH] riscv: Fix kernel stack size when KASAN is enabled BugLink: https://bugs.launchpad.net/bugs/2089884 commit cfb10de18538e383dbc4f3ce7f477ce49287ff3d upstream. We use Kconfig to select the kernel stack size, doubling the default size if KASAN is enabled. But that actually only works if KASAN is selected from the beginning, meaning that if KASAN config is added later (for example using menuconfig), CONFIG_THREAD_SIZE_ORDER won't be updated, keeping the default size, which is not enough for KASAN as reported in [1]. So fix this by moving the logic to compute the right kernel stack into a header. Fixes: a7555f6b62e7 ("riscv: stack: Add config of thread stack size") Reported-by: syzbot+ba9eac24453387a9d502@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000eb301906222aadc2@google.com/ [1] Cc: stable@vger.kernel.org Signed-off-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20240917150328.59831-1-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt Signed-off-by: Greg Kroah-Hartman Signed-off-by: Koichiro Den Signed-off-by: Roxana Nicolescu --- arch/riscv/Kconfig | 3 +-- arch/riscv/include/asm/thread_info.h | 7 ++++++- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index b7a83e9258c5..ea552b2c8906 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -685,8 +685,7 @@ config IRQ_STACKS config THREAD_SIZE_ORDER int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT range 0 4 - default 1 if 32BIT && !KASAN - default 3 if 64BIT && KASAN + default 1 if 32BIT default 2 help Specify the Pages of thread stack size (from 4KB to 64KB), which also diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h index 5d473343634b..eec9d4394f5b 100644 --- a/arch/riscv/include/asm/thread_info.h +++ b/arch/riscv/include/asm/thread_info.h @@ -12,7 +12,12 @@ #include /* thread information allocation */ -#define THREAD_SIZE_ORDER CONFIG_THREAD_SIZE_ORDER +#ifdef CONFIG_KASAN +#define KASAN_STACK_ORDER 1 +#else +#define KASAN_STACK_ORDER 0 +#endif +#define THREAD_SIZE_ORDER (CONFIG_THREAD_SIZE_ORDER + KASAN_STACK_ORDER) #define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER) /*