diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2017-11-24 23:54:22 +0000 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2017-12-17 22:14:21 +0000 |
| commit | c608906165355089a4de3c9133c72e81e011096c (patch) | |
| tree | cc1a76bc86bdcc8f0e69e4e3cb7874dcfccd26d2 /arch/arm/kernel/stacktrace.c | |
| parent | 75fea300d73ae5b18957949a53ec770daaeb6fc2 (diff) | |
ARM: probes: avoid adding kprobes to sensitive kernel-entry/exit code
Avoid adding kprobes to any of the kernel entry/exit or startup
assembly code, or code in the identity-mapped region. This code does
not conform to the standard C conventions, which means that the
expectations of the kprobes code is not forfilled.
Placing kprobes at some of these locations results in the kernel trying
to return to userspace addresses while retaining the CPU in kernel mode.
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel/stacktrace.c')
| -rw-r--r-- | arch/arm/kernel/stacktrace.c | 14 |
1 files changed, 2 insertions, 12 deletions
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index 65228bf4c6df..a56e7c856ab5 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -3,6 +3,7 @@ #include <linux/sched/debug.h> #include <linux/stacktrace.h> +#include <asm/sections.h> #include <asm/stacktrace.h> #include <asm/traps.h> @@ -63,7 +64,6 @@ EXPORT_SYMBOL(walk_stackframe); #ifdef CONFIG_STACKTRACE struct stack_trace_data { struct stack_trace *trace; - unsigned long last_pc; unsigned int no_sched_functions; unsigned int skip; }; @@ -87,16 +87,7 @@ static int save_trace(struct stackframe *frame, void *d) if (trace->nr_entries >= trace->max_entries) return 1; - /* - * in_exception_text() is designed to test if the PC is one of - * the functions which has an exception stack above it, but - * unfortunately what is in frame->pc is the return LR value, - * not the saved PC value. So, we need to track the previous - * frame PC value when doing this. - */ - addr = data->last_pc; - data->last_pc = frame->pc; - if (!in_exception_text(addr)) + if (!in_entry_text(frame->pc)) return 0; regs = (struct pt_regs *)frame->sp; @@ -114,7 +105,6 @@ static noinline void __save_stack_trace(struct task_struct *tsk, struct stackframe frame; data.trace = trace; - data.last_pc = ULONG_MAX; data.skip = trace->skip; data.no_sched_functions = nosched; |