diff options
Diffstat (limited to 'debian/patches-rt/0063-arm-Disable-FAST_GUP-on-PREEMPT_RT-if-HIGHPTE-is-als.patch')
| -rw-r--r-- | debian/patches-rt/0063-arm-Disable-FAST_GUP-on-PREEMPT_RT-if-HIGHPTE-is-als.patch | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/debian/patches-rt/0063-arm-Disable-FAST_GUP-on-PREEMPT_RT-if-HIGHPTE-is-als.patch b/debian/patches-rt/0063-arm-Disable-FAST_GUP-on-PREEMPT_RT-if-HIGHPTE-is-als.patch new file mode 100644 index 000000000..a621f83c1 --- /dev/null +++ b/debian/patches-rt/0063-arm-Disable-FAST_GUP-on-PREEMPT_RT-if-HIGHPTE-is-als.patch @@ -0,0 +1,43 @@ +From 14bcb121d2c7101a9a10e6a00e88828b2e9ec99b Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Tue, 23 Jan 2024 12:56:21 +0100 +Subject: [PATCH 63/64] arm: Disable FAST_GUP on PREEMPT_RT if HIGHPTE is also + enabled. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.1/older/patches-6.1.82-rt27.tar.xz + +gup_pgd_range() is invoked with disabled interrupts and invokes +__kmap_local_page_prot() via pte_offset_map(), gup_p4d_range(). +With HIGHPTE enabled, __kmap_local_page_prot() invokes kmap_high_get() +which uses a spinlock_t via lock_kmap_any(). This leads to an +sleeping-while-atomic error on PREEMPT_RT because spinlock_t becomes a +sleeping lock and must not be acquired in atomic context. + +The loop in map_new_virtual() uses wait_queue_head_t for wake up which +also is using a spinlock_t. + +Limit HAVE_FAST_GUP additionaly to remain disabled on PREEMPT_RT with +HIGHPTE enabled. + +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +(cherry picked from commit 02cf5a345530b4d3a94093f0b5c784701c2e7c6a) +Signed-off-by: Clark Williams <clark.williams@gmail.com> +--- + arch/arm/Kconfig | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig +index d1f2e062ce0b..5d92aef787e3 100644 +--- a/arch/arm/Kconfig ++++ b/arch/arm/Kconfig +@@ -95,7 +95,7 @@ config ARM + select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE + select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU + select HAVE_EXIT_THREAD +- select HAVE_FAST_GUP if ARM_LPAE ++ select HAVE_FAST_GUP if ARM_LPAE && !(PREEMPT_RT && HIGHPTE) + select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL + select HAVE_FUNCTION_GRAPH_TRACER + select HAVE_FUNCTION_TRACER if !XIP_KERNEL +-- +2.44.0 + |