diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2016-08-18 18:59:08 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-08-18 19:41:33 +0300 |
| commit | 4950d6d48a0c43cc61d0bbb76fb10e0214b79c66 (patch) | |
| tree | d73a8e4b7c0670f0183862261808f6abb23ae36e /arch/x86 | |
| parent | 8b927d734122f3021c5999aaeffaa2a36ab224c2 (diff) | |
| download | linux-4950d6d48a0c43cc61d0bbb76fb10e0214b79c66.tar.xz | |
x86/dumpstack: Remove 64-byte gap at end of irq stack
There has been a 64-byte gap at the end of the irq stack for at least 12
years. It predates git history, and I can't find any good reason for
it. Remove it. What's the worst that could happen?
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/14f9281c5475cc44af95945ea7546bff2e3836db.1471535549.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 9 | ||||
| -rw-r--r-- | arch/x86/kernel/setup_percpu.c | 2 |
3 files changed, 5 insertions, 8 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 809eda03c527..6ef55e83fb8a 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1281,7 +1281,7 @@ DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned = EXPORT_PER_CPU_SYMBOL(current_task); DEFINE_PER_CPU(char *, irq_stack_ptr) = - init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64; + init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE; DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1; diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index daf9f6321856..066eb5c77fd6 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -103,9 +103,6 @@ in_irq_stack(unsigned long *stack, unsigned long *irq_stack, return (stack >= irq_stack && stack < irq_stack_end); } -static const unsigned long irq_stack_size = - (IRQ_STACK_SIZE - 64) / sizeof(unsigned long); - enum stack_type { STACK_IS_UNKNOWN, STACK_IS_NORMAL, @@ -133,7 +130,7 @@ analyze_stack(int cpu, struct task_struct *task, unsigned long *stack, return STACK_IS_NORMAL; *stack_end = irq_stack; - irq_stack = irq_stack - irq_stack_size; + irq_stack -= (IRQ_STACK_SIZE / sizeof(long)); if (in_irq_stack(stack, irq_stack, *stack_end)) return STACK_IS_IRQ; @@ -256,8 +253,8 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, preempt_disable(); cpu = smp_processor_id(); - irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu)); - irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE); + irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu)); + irq_stack = irq_stack_end - (IRQ_STACK_SIZE / sizeof(long)); /* * Debugging aid: "show_stack(NULL, NULL);" prints the diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index 7a40e068302d..d182799c4264 100644 --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -246,7 +246,7 @@ void __init setup_per_cpu_areas(void) #ifdef CONFIG_X86_64 per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack_union.irq_stack, cpu) + - IRQ_STACK_SIZE - 64; + IRQ_STACK_SIZE; #endif #ifdef CONFIG_NUMA per_cpu(x86_cpu_to_node_map, cpu) = |