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Diffstat (limited to 'arch/x86/kernel/unwind_frame.c')
-rw-r--r--arch/x86/kernel/unwind_frame.c38
1 files changed, 36 insertions, 2 deletions
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index d145a0b1f529..3dc26f95d46e 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -44,7 +44,8 @@ static void unwind_dump(struct unwind_state *state)
state->stack_info.type, state->stack_info.next_sp,
state->stack_mask, state->graph_idx);
- for (sp = state->orig_sp; sp; sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
+ for (sp = PTR_ALIGN(state->orig_sp, sizeof(long)); sp;
+ sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
if (get_stack_info(sp, state->task, &stack_info, &visit_mask))
break;
@@ -174,6 +175,7 @@ static bool is_last_task_frame(struct unwind_state *state)
* This determines if the frame pointer actually contains an encoded pointer to
* pt_regs on the stack. See ENCODE_FRAME_POINTER.
*/
+#ifdef CONFIG_X86_64
static struct pt_regs *decode_frame_pointer(unsigned long *bp)
{
unsigned long regs = (unsigned long)bp;
@@ -183,6 +185,23 @@ static struct pt_regs *decode_frame_pointer(unsigned long *bp)
return (struct pt_regs *)(regs & ~0x1);
}
+#else
+static struct pt_regs *decode_frame_pointer(unsigned long *bp)
+{
+ unsigned long regs = (unsigned long)bp;
+
+ if (regs & 0x80000000)
+ return NULL;
+
+ return (struct pt_regs *)(regs | 0x80000000);
+}
+#endif
+
+#ifdef CONFIG_X86_32
+#define KERNEL_REGS_SIZE (sizeof(struct pt_regs) - 2*sizeof(long))
+#else
+#define KERNEL_REGS_SIZE (sizeof(struct pt_regs))
+#endif
static bool update_stack_state(struct unwind_state *state,
unsigned long *next_bp)
@@ -202,7 +221,7 @@ static bool update_stack_state(struct unwind_state *state,
regs = decode_frame_pointer(next_bp);
if (regs) {
frame = (unsigned long *)regs;
- len = regs_size(regs);
+ len = KERNEL_REGS_SIZE;
state->got_irq = true;
} else {
frame = next_bp;
@@ -226,6 +245,14 @@ static bool update_stack_state(struct unwind_state *state,
frame < prev_frame_end)
return false;
+ /*
+ * On 32-bit with user mode regs, make sure the last two regs are safe
+ * to access:
+ */
+ if (IS_ENABLED(CONFIG_X86_32) && regs && user_mode(regs) &&
+ !on_stack(info, frame, len + 2*sizeof(long)))
+ return false;
+
/* Move state to the next frame: */
if (regs) {
state->regs = regs;
@@ -328,6 +355,13 @@ bad_address:
state->regs->sp < (unsigned long)task_pt_regs(state->task))
goto the_end;
+ /*
+ * There are some known frame pointer issues on 32-bit. Disable
+ * unwinder warnings on 32-bit until it gets objtool support.
+ */
+ if (IS_ENABLED(CONFIG_X86_32))
+ goto the_end;
+
if (state->regs) {
printk_deferred_once(KERN_WARNING
"WARNING: kernel stack regs at %p in %s:%d has bad 'bp' value %p\n",

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