From 12964443e8d1914010f9269f9f9abc4e122bc6ca Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 1 Aug 2017 18:51:15 +0100 Subject: arm64: add on_accessible_stack() Both unwind_frame() and dump_backtrace() try to check whether a stack address is sane to access, with very similar logic. Both will need updating in order to handle overflow stacks. Factor out this logic into a helper, so that we can avoid further duplication when we add overflow stacks. Signed-off-by: Mark Rutland Reviewed-by: Will Deacon Tested-by: Laura Abbott Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: James Morse --- arch/arm64/kernel/stacktrace.c | 7 +------ arch/arm64/kernel/traps.c | 3 +-- 2 files changed, 2 insertions(+), 8 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 35588caad9d0..3144584617e7 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -50,12 +50,7 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) if (!tsk) tsk = current; - /* - * Switching between stacks is valid when tracing current and in - * non-preemptible context. - */ - if (!(tsk == current && !preemptible() && on_irq_stack(fp)) && - !on_task_stack(tsk, fp)) + if (!on_accessible_stack(tsk, fp)) return -EINVAL; frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 9633773ca42c..d01c5988354b 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -193,8 +193,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) if (in_entry_text(frame.pc)) { stack = frame.fp - offsetof(struct pt_regs, stackframe); - if (on_task_stack(tsk, stack) || - (tsk == current && !preemptible() && on_irq_stack(stack))) + if (on_accessible_stack(tsk, stack)) dump_mem("", "Exception stack", stack, stack + sizeof(struct pt_regs)); } -- cgit v1.2.3-59-g8ed1b