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-rw-r--r--arch/x86/kernel/dumpstack.c6
-rw-r--r--arch/x86/kernel/unwind_frame.c11
2 files changed, 17 insertions, 0 deletions
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index afae4dd77495..476eb504084e 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -177,6 +177,12 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
}
}
+/*
+ * This function reads pointers from the stack and dereferences them. The
+ * pointers may not have their KMSAN shadow set up properly, which may result
+ * in false positive reports. Disable instrumentation to avoid those.
+ */
+__no_kmsan_checks
static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, const char *log_lvl)
{
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index 8e1c50c86e5d..d8ba93778ae3 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -183,6 +183,16 @@ static struct pt_regs *decode_frame_pointer(unsigned long *bp)
}
#endif
+/*
+ * While walking the stack, KMSAN may stomp on stale locals from other
+ * functions that were marked as uninitialized upon function exit, and
+ * now hold the call frame information for the current function (e.g. the frame
+ * pointer). Because KMSAN does not specifically mark call frames as
+ * initialized, false positive reports are possible. To prevent such reports,
+ * we mark the functions scanning the stack (here and below) with
+ * __no_kmsan_checks.
+ */
+__no_kmsan_checks
static bool update_stack_state(struct unwind_state *state,
unsigned long *next_bp)
{
@@ -250,6 +260,7 @@ static bool update_stack_state(struct unwind_state *state,
return true;
}
+__no_kmsan_checks
bool unwind_next_frame(struct unwind_state *state)
{
struct pt_regs *regs;