Commit c060f932 authored by Puranjay Mohan's avatar Puranjay Mohan Committed by Catalin Marinas
Browse files

arm64: stacktrace: fix the usage of ftrace_graph_ret_addr() 



ftrace_graph_ret_addr() takes an 'idx' integer pointer that is used to
optimize the stack unwinding process. arm64 currently passes `NULL` for
this parameter which stops it from utilizing these optimizations.

Further, the current code for ftrace_graph_ret_addr() will just return
the passed in return address if it is NULL which will break this usage.

Pass a valid integer pointer to ftrace_graph_ret_addr() similar to
x86_64's stack unwinder.

Signed-off-by: default avatarPuranjay Mohan <puranjay@kernel.org>
Fixes: 29c1c24a ("function_graph: Fix up ftrace_graph_ret_addr()")
Acked-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: default avatarWill Deacon <will@kernel.org>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20240618162342.28275-1-puranjay@kernel.org


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 75c8f387

arch/arm64/kernel/stacktrace.c

+3 −1
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
 *

 * @common:      Common unwind state.

 * @task:        The task being unwound.

 * @graph_idx:   Used by ftrace_graph_ret_addr() for optimized stack unwinding.

 * @kr_cur:      When KRETPROBES is selected, holds the kretprobe instance

 *               associated with the most recently encountered replacement lr

 *               value.
@@ -32,6 +33,7 @@ 
struct kunwind_state {

	struct unwind_state common;

	struct task_struct *task;

	int graph_idx;

#ifdef CONFIG_KRETPROBES

	struct llist_node *kr_cur;

#endif
@@ -106,7 +108,7 @@ kunwind_recover_return_address(struct kunwind_state *state) 
	if (state->task->ret_stack &&

	    (state->common.pc == (unsigned long)return_to_handler)) {

		unsigned long orig_pc;

		orig_pc = ftrace_graph_ret_addr(state->task, NULL,

		orig_pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,

						state->common.pc,

						(void *)state->common.fp);

		if (WARN_ON_ONCE(state->common.pc == orig_pc))