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Merge branch 'for-next/stacktrace' into for-next/core
* for-next/stacktrace: arm64: Copy the task argument to unwind_state arm64: Split unwind_init() arm64: stacktrace: use non-atomic __set_bit arm64: kasan: do not instrument stacktrace.c
This commit is contained in:
commit
cb20311e5e
2 changed files with 79 additions and 23 deletions
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@ -14,6 +14,11 @@ CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE)
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CFLAGS_REMOVE_syscall.o = -fstack-protector -fstack-protector-strong
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CFLAGS_syscall.o += -fno-stack-protector
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# When KASAN is enabled, a stack trace is recorded for every alloc/free, which
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# can significantly impact performance. Avoid instrumenting the stack trace
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# collection code to minimize this impact.
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KASAN_SANITIZE_stacktrace.o := n
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# It's not safe to invoke KCOV when portions of the kernel environment aren't
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# available or are out-of-sync with HW state. Since `noinstr` doesn't always
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# inhibit KCOV instrumentation, disable it for the entire compilation unit.
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@ -38,6 +38,8 @@
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* @kr_cur: When KRETPROBES is selected, holds the kretprobe instance
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* associated with the most recently encountered replacement lr
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* value.
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*
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* @task: The task being unwound.
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*/
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struct unwind_state {
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unsigned long fp;
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@ -48,13 +50,13 @@ struct unwind_state {
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#ifdef CONFIG_KRETPROBES
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struct llist_node *kr_cur;
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#endif
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struct task_struct *task;
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};
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static notrace void unwind_init(struct unwind_state *state, unsigned long fp,
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unsigned long pc)
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static void unwind_init_common(struct unwind_state *state,
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struct task_struct *task)
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{
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state->fp = fp;
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state->pc = pc;
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state->task = task;
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#ifdef CONFIG_KRETPROBES
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state->kr_cur = NULL;
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#endif
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@ -72,7 +74,57 @@ static notrace void unwind_init(struct unwind_state *state, unsigned long fp,
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state->prev_fp = 0;
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state->prev_type = STACK_TYPE_UNKNOWN;
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}
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NOKPROBE_SYMBOL(unwind_init);
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/*
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* Start an unwind from a pt_regs.
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*
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* The unwind will begin at the PC within the regs.
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*
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* The regs must be on a stack currently owned by the calling task.
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*/
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static inline void unwind_init_from_regs(struct unwind_state *state,
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struct pt_regs *regs)
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{
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unwind_init_common(state, current);
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state->fp = regs->regs[29];
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state->pc = regs->pc;
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}
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/*
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* Start an unwind from a caller.
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*
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* The unwind will begin at the caller of whichever function this is inlined
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* into.
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*
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* The function which invokes this must be noinline.
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*/
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static __always_inline void unwind_init_from_caller(struct unwind_state *state)
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{
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unwind_init_common(state, current);
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state->fp = (unsigned long)__builtin_frame_address(1);
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state->pc = (unsigned long)__builtin_return_address(0);
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}
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/*
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* Start an unwind from a blocked task.
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*
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* The unwind will begin at the blocked tasks saved PC (i.e. the caller of
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* cpu_switch_to()).
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*
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* The caller should ensure the task is blocked in cpu_switch_to() for the
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* duration of the unwind, or the unwind will be bogus. It is never valid to
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* call this for the current task.
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*/
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static inline void unwind_init_from_task(struct unwind_state *state,
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struct task_struct *task)
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{
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unwind_init_common(state, task);
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state->fp = thread_saved_fp(task);
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state->pc = thread_saved_pc(task);
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}
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/*
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* Unwind from one frame record (A) to the next frame record (B).
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@ -81,9 +133,9 @@ NOKPROBE_SYMBOL(unwind_init);
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* records (e.g. a cycle), determined based on the location and fp value of A
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* and the location (but not the fp value) of B.
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*/
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static int notrace unwind_next(struct task_struct *tsk,
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struct unwind_state *state)
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static int notrace unwind_next(struct unwind_state *state)
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{
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struct task_struct *tsk = state->task;
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unsigned long fp = state->fp;
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struct stack_info info;
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@ -117,15 +169,15 @@ static int notrace unwind_next(struct task_struct *tsk,
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if (fp <= state->prev_fp)
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return -EINVAL;
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} else {
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set_bit(state->prev_type, state->stacks_done);
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__set_bit(state->prev_type, state->stacks_done);
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}
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/*
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* Record this frame record's values and location. The prev_fp and
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* prev_type are only meaningful to the next unwind_next() invocation.
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*/
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state->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
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state->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
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state->fp = READ_ONCE(*(unsigned long *)(fp));
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state->pc = READ_ONCE(*(unsigned long *)(fp + 8));
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state->prev_fp = fp;
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state->prev_type = info.type;
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@ -157,8 +209,7 @@ static int notrace unwind_next(struct task_struct *tsk,
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}
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NOKPROBE_SYMBOL(unwind_next);
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static void notrace unwind(struct task_struct *tsk,
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struct unwind_state *state,
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static void notrace unwind(struct unwind_state *state,
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stack_trace_consume_fn consume_entry, void *cookie)
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{
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while (1) {
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@ -166,7 +217,7 @@ static void notrace unwind(struct task_struct *tsk,
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if (!consume_entry(cookie, state->pc))
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break;
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ret = unwind_next(tsk, state);
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ret = unwind_next(state);
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if (ret < 0)
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break;
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}
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@ -212,15 +263,15 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
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{
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struct unwind_state state;
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if (regs)
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unwind_init(&state, regs->regs[29], regs->pc);
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else if (task == current)
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unwind_init(&state,
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(unsigned long)__builtin_frame_address(1),
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(unsigned long)__builtin_return_address(0));
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else
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unwind_init(&state, thread_saved_fp(task),
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thread_saved_pc(task));
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if (regs) {
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if (task != current)
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return;
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unwind_init_from_regs(&state, regs);
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} else if (task == current) {
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unwind_init_from_caller(&state);
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} else {
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unwind_init_from_task(&state, task);
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}
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unwind(task, &state, consume_entry, cookie);
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unwind(&state, consume_entry, cookie);
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}
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