From b922edc36103390d355ec80bc3855581acd2bbb3 Mon Sep 17 00:00:00 2001 From: "Madhavan T. Venkataraman" Date: Fri, 17 Jun 2022 13:02:15 -0500 Subject: [PATCH] BACKPORT: arm64: Copy the task argument to unwind_state Copy the task argument passed to arch_stack_walk() to unwind_state so that it can be passed to unwind functions via unwind_state rather than as a separate argument. The task is a fundamental part of the unwind state. Signed-off-by: Madhavan T. Venkataraman Reviewed-by: Mark Brown Acked-by: Mark Rutland Link: https://lore.kernel.org/r/20220617180219.20352-3-madvenka@linux.microsoft.com Signed-off-by: Will Deacon (cherry picked from commit 82a592c13b0aeff94d84d54183dae0b26384c95f) [willdeacon@: Resolve context conflict with kretprobes field in 'struct unwind_state'] Signed-off-by: Will Deacon Bug: 233587962 Bug: 233588291 Change-Id: Icf29c7da8111dd5f7a25d99e6277a99c78e1ec23 --- arch/arm64/kernel/stacktrace.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 6fbd0e37a219..7cd43598b7f3 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -34,6 +34,8 @@ * @prev_type: The type of stack this frame record was on, or a synthetic * value of STACK_TYPE_UNKNOWN. This is used to detect a * transition from one stack to another. + * + * @task: The task being unwound. */ struct unwind_state { unsigned long fp; @@ -41,10 +43,14 @@ struct unwind_state { DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES); unsigned long prev_fp; enum stack_type prev_type; + struct task_struct *task; }; -static void unwind_init_common(struct unwind_state *state) +static void unwind_init_common(struct unwind_state *state, + struct task_struct *task) { + state->task = task; + /* * Prime the first unwind. * @@ -69,7 +75,7 @@ static void unwind_init_common(struct unwind_state *state) static inline void unwind_init_from_regs(struct unwind_state *state, struct pt_regs *regs) { - unwind_init_common(state); + unwind_init_common(state, current); state->fp = regs->regs[29]; state->pc = regs->pc; @@ -85,7 +91,7 @@ static inline void unwind_init_from_regs(struct unwind_state *state, */ static __always_inline void unwind_init_from_caller(struct unwind_state *state) { - unwind_init_common(state); + unwind_init_common(state, current); state->fp = (unsigned long)__builtin_frame_address(1); state->pc = (unsigned long)__builtin_return_address(0); @@ -104,7 +110,7 @@ static __always_inline void unwind_init_from_caller(struct unwind_state *state) static inline void unwind_init_from_task(struct unwind_state *state, struct task_struct *task) { - unwind_init_common(state); + unwind_init_common(state, task); state->fp = thread_saved_fp(task); state->pc = thread_saved_pc(task); @@ -117,9 +123,9 @@ static inline void unwind_init_from_task(struct unwind_state *state, * records (e.g. a cycle), determined based on the location and fp value of A * and the location (but not the fp value) of B. */ -static int notrace unwind_next(struct task_struct *tsk, - struct unwind_state *state) +static int notrace unwind_next(struct unwind_state *state) { + struct task_struct *tsk = state->task; unsigned long fp = state->fp; struct stack_info info; @@ -189,8 +195,7 @@ static int notrace unwind_next(struct task_struct *tsk, } NOKPROBE_SYMBOL(unwind_next); -static void notrace unwind(struct task_struct *tsk, - struct unwind_state *state, +static void notrace unwind(struct unwind_state *state, stack_trace_consume_fn consume_entry, void *cookie) { while (1) { @@ -198,7 +203,7 @@ static void notrace unwind(struct task_struct *tsk, if (!consume_entry(cookie, state->pc)) break; - ret = unwind_next(tsk, state); + ret = unwind_next(state); if (ret < 0) break; } @@ -245,12 +250,15 @@ noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry, { struct unwind_state state; - if (regs) + if (regs) { + if (task != current) + return; unwind_init_from_regs(&state, regs); - else if (task == current) + } else if (task == current) { unwind_init_from_caller(&state); - else + } else { unwind_init_from_task(&state, task); + } - unwind(task, &state, consume_entry, cookie); + unwind(&state, consume_entry, cookie); }