Reorganize the unwinding in __save_stack_trace_reliable, so that we
don't need to set another variable -- unwind_state->error. In case,
unwinding fails, we fail after the for loop too. The only way to escape
the loop successfully is via the 'if (user_mode(regs))' check now.
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/include/asm/unwind.h | 6 ------
arch/x86/kernel/stacktrace.c | 15 ++++++---------
arch/x86/kernel/unwind_frame.c | 2 --
3 files changed, 6 insertions(+), 17 deletions(-)
diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
index 5be2fb23825a..6f90295e6547 100644
--- a/arch/x86/include/asm/unwind.h
+++ b/arch/x86/include/asm/unwind.h
@@ -15,7 +15,6 @@ struct unwind_state {
unsigned long stack_mask;
struct task_struct *task;
int graph_idx;
- bool error;
#if defined(CONFIG_UNWINDER_ORC)
bool signal, full_regs;
unsigned long sp, bp, ip;
@@ -40,11 +39,6 @@ static inline bool unwind_done(struct unwind_state *state)
return state->stack_info.type == STACK_TYPE_UNKNOWN;
}
-static inline bool unwind_error(struct unwind_state *state)
-{
- return state->error;
-}
-
static inline
void unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame)
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index b088d4f9e43e..9193607e3ead 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -104,16 +104,16 @@ __save_stack_trace_reliable(struct stack_trace *trace,
regs = unwind_get_entry_regs(&state);
if (regs) {
+ if (user_mode(regs))
+ goto success;
+
/*
* Kernel mode registers on the stack indicate an
* in-kernel interrupt or exception (e.g., preemption
* or a page fault), which can make frame pointers
* unreliable.
*/
- if (!user_mode(regs))
- return -EINVAL;
-
- break;
+ return -EINVAL;
}
addr = unwind_get_return_address(&state);
@@ -132,12 +132,9 @@ __save_stack_trace_reliable(struct stack_trace *trace,
return -EINVAL;
}
- /* Check for stack corruption */
- if (unwind_error(&state)) {
- STACKTRACE_DUMP_ONCE(task);
- return -EINVAL;
- }
+ return -EINVAL;
+success:
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index 3dc26f95d46e..0c08a56adabe 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -332,8 +332,6 @@ bool unwind_next_frame(struct unwind_state *state)
return true;
bad_address:
- state->error = true;
-
/*
* When unwinding a non-current task, the task might actually be
* running on another CPU, in which case it could be modifying its
--
2.15.1
--
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