| Message ID | 156378172702.12011.1144595747474511323.stgit@devnote2 (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: kprobes: Fix some bugs in arm64 kprobes | expand |
Hi, On 22/07/2019 08:48, Masami Hiramatsu wrote: > Prohibit probing on return_address() and subroutines which > is called from return_address(), since the it is invoked from > trace_hardirqs_off() which is also kprobe blacklisted. (Nits: "which are called" and "since it is") > diff --git a/arch/arm64/kernel/return_address.c b/arch/arm64/kernel/return_address.c > index b21cba90f82d..7f8a143268b0 100644 > --- a/arch/arm64/kernel/return_address.c > +++ b/arch/arm64/kernel/return_address.c > @@ -8,6 +8,7 @@ > > #include <linux/export.h> > #include <linux/ftrace.h> > +#include <linux/kprobes.h> > > #include <asm/stack_pointer.h> > #include <asm/stacktrace.h> > @@ -17,7 +18,7 @@ struct return_address_data { > void *addr; > }; > > -static int save_return_addr(struct stackframe *frame, void *d) > +static nokprobe_inline int save_return_addr(struct stackframe *frame, void *d) This nokprobe_inline ends up as __always_inline if kprobes is enabled. What do we expect the compiler to do with this? save_return_addr is passed as a function-pointer to walk_stackframe()... I don't see how the compiler can inline it! This would be needed for on_accessible_stack(). Should we cover ftrace_graph_get_ret_stack()?, or is that already in hand? > { > struct return_address_data *data = d; > > @@ -52,3 +53,4 @@ void *return_address(unsigned int level) > return NULL; > } > EXPORT_SYMBOL_GPL(return_address); > +NOKPROBE_SYMBOL(return_address); Thanks, James
On Tue, 23 Jul 2019 17:04:21 +0100 James Morse <james.morse@arm.com> wrote: > Hi, > > On 22/07/2019 08:48, Masami Hiramatsu wrote: > > Prohibit probing on return_address() and subroutines which > > is called from return_address(), since the it is invoked from > > trace_hardirqs_off() which is also kprobe blacklisted. > > (Nits: "which are called" and "since it is") Thanks! > > > > diff --git a/arch/arm64/kernel/return_address.c b/arch/arm64/kernel/return_address.c > > index b21cba90f82d..7f8a143268b0 100644 > > --- a/arch/arm64/kernel/return_address.c > > +++ b/arch/arm64/kernel/return_address.c > > @@ -8,6 +8,7 @@ > > > > #include <linux/export.h> > > #include <linux/ftrace.h> > > +#include <linux/kprobes.h> > > > > #include <asm/stack_pointer.h> > > #include <asm/stacktrace.h> > > @@ -17,7 +18,7 @@ struct return_address_data { > > void *addr; > > }; > > > > -static int save_return_addr(struct stackframe *frame, void *d) > > +static nokprobe_inline int save_return_addr(struct stackframe *frame, void *d) > > This nokprobe_inline ends up as __always_inline if kprobes is enabled. > What do we expect the compiler to do with this? save_return_addr is passed as a > function-pointer to walk_stackframe()... I don't see how the compiler can inline it! Oops, that's my mistake. Then it should be NOKPROBE_SYMBOL. > > This would be needed for on_accessible_stack(). > Should we cover ftrace_graph_get_ret_stack()?, or is that already in hand? No, that is OK. It just covers that the functions which are involved in the kprobe execution path. ftrace_graph_ret_stack() is out of the debug exception handler. Thank you, > > { > > struct return_address_data *data = d; > > > > @@ -52,3 +53,4 @@ void *return_address(unsigned int level) > > return NULL; > > } > > EXPORT_SYMBOL_GPL(return_address); > > +NOKPROBE_SYMBOL(return_address); > > > Thanks, > > James
diff --git a/arch/arm64/kernel/return_address.c b/arch/arm64/kernel/return_address.c index b21cba90f82d..7f8a143268b0 100644 --- a/arch/arm64/kernel/return_address.c +++ b/arch/arm64/kernel/return_address.c @@ -8,6 +8,7 @@ #include <linux/export.h> #include <linux/ftrace.h> +#include <linux/kprobes.h> #include <asm/stack_pointer.h> #include <asm/stacktrace.h> @@ -17,7 +18,7 @@ struct return_address_data { void *addr; }; -static int save_return_addr(struct stackframe *frame, void *d) +static nokprobe_inline int save_return_addr(struct stackframe *frame, void *d) { struct return_address_data *data = d; @@ -52,3 +53,4 @@ void *return_address(unsigned int level) return NULL; } EXPORT_SYMBOL_GPL(return_address); +NOKPROBE_SYMBOL(return_address); diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 62d395151abe..cd7dab54d17b 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -7,6 +7,7 @@ #include <linux/kernel.h> #include <linux/export.h> #include <linux/ftrace.h> +#include <linux/kprobes.h> #include <linux/sched.h> #include <linux/sched/debug.h> #include <linux/sched/task_stack.h> @@ -73,6 +74,7 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) return 0; } +NOKPROBE_SYMBOL(unwind_frame); void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame, int (*fn)(struct stackframe *, void *), void *data) @@ -87,6 +89,7 @@ void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame, break; } } +NOKPROBE_SYMBOL(walk_stackframe); #ifdef CONFIG_STACKTRACE struct stack_trace_data {
Prohibit probing on return_address() and subroutines which is called from return_address(), since the it is invoked from trace_hardirqs_off() which is also kprobe blacklisted. Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- arch/arm64/kernel/return_address.c | 4 +++- arch/arm64/kernel/stacktrace.c | 3 +++ 2 files changed, 6 insertions(+), 1 deletion(-)