#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
+#include <linux/interrupt.h>
+#include <asm/sections.h>
#include <asm/ptrace.h>
#include <asm/bitops.h>
#include <asm/stacktrace.h>
val; \
})
-static void unwind_dump(struct unwind_state *state, unsigned long *sp)
+static void unwind_dump(struct unwind_state *state)
{
static bool dumped_before = false;
bool prev_zero, zero = false;
- unsigned long word;
+ unsigned long word, *sp;
+ struct stack_info stack_info = {0};
+ unsigned long visit_mask = 0;
if (dumped_before)
return;
dumped_before = true;
- printk_deferred("unwind stack type:%d next_sp:%p mask:%lx graph_idx:%d\n",
+ printk_deferred("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\n",
state->stack_info.type, state->stack_info.next_sp,
state->stack_mask, state->graph_idx);
- for (sp = state->orig_sp; sp < state->stack_info.end; sp++) {
- word = READ_ONCE_NOCHECK(*sp);
+ for (sp = state->orig_sp; sp; sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
+ if (get_stack_info(sp, state->task, &stack_info, &visit_mask))
+ break;
- prev_zero = zero;
- zero = word == 0;
+ for (; sp < stack_info.end; sp++) {
- if (zero) {
- if (!prev_zero)
- printk_deferred("%p: %016x ...\n", sp, 0);
- continue;
- }
+ word = READ_ONCE_NOCHECK(*sp);
+
+ prev_zero = zero;
+ zero = word == 0;
- printk_deferred("%p: %016lx (%pB)\n", sp, word, (void *)word);
+ if (zero) {
+ if (!prev_zero)
+ printk_deferred("%p: %0*x ...\n",
+ sp, BITS_PER_LONG/4, 0);
+ continue;
+ }
+
+ printk_deferred("%p: %0*lx (%pB)\n",
+ sp, BITS_PER_LONG/4, word, (void *)word);
+ }
}
}
unsigned long unwind_get_return_address(struct unwind_state *state)
{
- unsigned long addr;
- unsigned long *addr_p = unwind_get_return_address_ptr(state);
-
if (unwind_done(state))
return 0;
- if (state->regs && user_mode(state->regs))
- return 0;
-
- addr = READ_ONCE_TASK_STACK(state->task, *addr_p);
- addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, addr,
- addr_p);
-
- return __kernel_text_address(addr) ? addr : 0;
+ return __kernel_text_address(state->ip) ? state->ip : 0;
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);
return sizeof(*regs);
}
+static bool in_entry_code(unsigned long ip)
+{
+ char *addr = (char *)ip;
+
+ if (addr >= __entry_text_start && addr < __entry_text_end)
+ return true;
+
+#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
+ if (addr >= __irqentry_text_start && addr < __irqentry_text_end)
+ return true;
+#endif
+
+ return false;
+}
+
+static inline unsigned long *last_frame(struct unwind_state *state)
+{
+ return (unsigned long *)task_pt_regs(state->task) - 2;
+}
+
+static bool is_last_frame(struct unwind_state *state)
+{
+ return state->bp == last_frame(state);
+}
+
#ifdef CONFIG_X86_32
#define GCC_REALIGN_WORDS 3
#else
#define GCC_REALIGN_WORDS 1
#endif
-static bool is_last_task_frame(struct unwind_state *state)
+static inline unsigned long *last_aligned_frame(struct unwind_state *state)
+{
+ return last_frame(state) - GCC_REALIGN_WORDS;
+}
+
+static bool is_last_aligned_frame(struct unwind_state *state)
{
- unsigned long *last_bp = (unsigned long *)task_pt_regs(state->task) - 2;
- unsigned long *aligned_bp = last_bp - GCC_REALIGN_WORDS;
+ unsigned long *last_bp = last_frame(state);
+ unsigned long *aligned_bp = last_aligned_frame(state);
/*
- * We have to check for the last task frame at two different locations
- * because gcc can occasionally decide to realign the stack pointer and
- * change the offset of the stack frame in the prologue of a function
- * called by head/entry code. Examples:
+ * GCC can occasionally decide to realign the stack pointer and change
+ * the offset of the stack frame in the prologue of a function called
+ * by head/entry code. Examples:
*
* <start_secondary>:
* push %edi
* push %rbp
* mov %rsp,%rbp
*
- * Note that after aligning the stack, it pushes a duplicate copy of
- * the return address before pushing the frame pointer.
+ * After aligning the stack, it pushes a duplicate copy of the return
+ * address before pushing the frame pointer.
*/
- return (state->bp == last_bp ||
- (state->bp == aligned_bp && *(aligned_bp+1) == *(last_bp+1)));
+ return (state->bp == aligned_bp && *(aligned_bp + 1) == *(last_bp + 1));
+}
+
+static bool is_last_ftrace_frame(struct unwind_state *state)
+{
+ unsigned long *last_bp = last_frame(state);
+ unsigned long *last_ftrace_bp = last_bp - 3;
+
+ /*
+ * When unwinding from an ftrace handler of a function called by entry
+ * code, the stack layout of the last frame is:
+ *
+ * bp
+ * parent ret addr
+ * bp
+ * function ret addr
+ * parent ret addr
+ * pt_regs
+ * -----------------
+ */
+ return (state->bp == last_ftrace_bp &&
+ *state->bp == *(state->bp + 2) &&
+ *(state->bp + 1) == *(state->bp + 4));
+}
+
+static bool is_last_task_frame(struct unwind_state *state)
+{
+ return is_last_frame(state) || is_last_aligned_frame(state) ||
+ is_last_ftrace_frame(state);
}
/*
return (struct pt_regs *)(regs & ~0x1);
}
-static bool update_stack_state(struct unwind_state *state, void *addr,
- size_t len)
+static bool update_stack_state(struct unwind_state *state,
+ unsigned long *next_bp)
{
struct stack_info *info = &state->stack_info;
- enum stack_type orig_type = info->type;
+ enum stack_type prev_type = info->type;
+ struct pt_regs *regs;
+ unsigned long *frame, *prev_frame_end, *addr_p, addr;
+ size_t len;
+
+ if (state->regs)
+ prev_frame_end = (void *)state->regs + regs_size(state->regs);
+ else
+ prev_frame_end = (void *)state->bp + FRAME_HEADER_SIZE;
+
+ /* Is the next frame pointer an encoded pointer to pt_regs? */
+ regs = decode_frame_pointer(next_bp);
+ if (regs) {
+ frame = (unsigned long *)regs;
+ len = regs_size(regs);
+ state->got_irq = true;
+ } else {
+ frame = next_bp;
+ len = FRAME_HEADER_SIZE;
+ }
/*
- * If addr isn't on the current stack, switch to the next one.
+ * If the next bp isn't on the current stack, switch to the next one.
*
* We may have to traverse multiple stacks to deal with the possibility
- * that 'info->next_sp' could point to an empty stack and 'addr' could
- * be on a subsequent stack.
+ * that info->next_sp could point to an empty stack and the next bp
+ * could be on a subsequent stack.
*/
- while (!on_stack(info, addr, len))
+ while (!on_stack(info, frame, len))
if (get_stack_info(info->next_sp, state->task, info,
&state->stack_mask))
return false;
- if (!state->orig_sp || info->type != orig_type)
- state->orig_sp = addr;
+ /* Make sure it only unwinds up and doesn't overlap the prev frame: */
+ if (state->orig_sp && state->stack_info.type == prev_type &&
+ frame < prev_frame_end)
+ return false;
+
+ /* Move state to the next frame: */
+ if (regs) {
+ state->regs = regs;
+ state->bp = NULL;
+ } else {
+ state->bp = next_bp;
+ state->regs = NULL;
+ }
+
+ /* Save the return address: */
+ if (state->regs && user_mode(state->regs))
+ state->ip = 0;
+ else {
+ addr_p = unwind_get_return_address_ptr(state);
+ addr = READ_ONCE_TASK_STACK(state->task, *addr_p);
+ state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ addr, addr_p);
+ }
+
+ /* Save the original stack pointer for unwind_dump(): */
+ if (!state->orig_sp)
+ state->orig_sp = frame;
return true;
}
bool unwind_next_frame(struct unwind_state *state)
{
struct pt_regs *regs;
- unsigned long *next_bp, *next_frame;
- size_t next_len;
- enum stack_type prev_type = state->stack_info.type;
+ unsigned long *next_bp;
if (unwind_done(state))
return false;
- /* have we reached the end? */
+ /* Have we reached the end? */
if (state->regs && user_mode(state->regs))
goto the_end;
*/
state->regs = regs;
state->bp = NULL;
+ state->ip = 0;
return true;
}
- /* get the next frame pointer */
+ /* Get the next frame pointer: */
if (state->regs)
next_bp = (unsigned long *)state->regs->bp;
else
- next_bp = (unsigned long *)READ_ONCE_TASK_STACK(state->task,*state->bp);
-
- /* is the next frame pointer an encoded pointer to pt_regs? */
- regs = decode_frame_pointer(next_bp);
- if (regs) {
- next_frame = (unsigned long *)regs;
- next_len = sizeof(*regs);
- } else {
- next_frame = next_bp;
- next_len = FRAME_HEADER_SIZE;
- }
-
- /* make sure the next frame's data is accessible */
- if (!update_stack_state(state, next_frame, next_len)) {
- /*
- * Don't warn on bad regs->bp. An interrupt in entry code
- * might cause a false positive warning.
- */
- if (state->regs)
- goto the_end;
+ next_bp = (unsigned long *)READ_ONCE_TASK_STACK(state->task, *state->bp);
+ /* Move to the next frame if it's safe: */
+ if (!update_stack_state(state, next_bp))
goto bad_address;
- }
-
- /* Make sure it only unwinds up and doesn't overlap the last frame: */
- if (state->stack_info.type == prev_type) {
- if (state->regs && (void *)next_frame < (void *)state->regs + regs_size(state->regs))
- goto bad_address;
-
- if (state->bp && (void *)next_frame < (void *)state->bp + FRAME_HEADER_SIZE)
- goto bad_address;
- }
-
- /* move to the next frame */
- if (regs) {
- state->regs = regs;
- state->bp = NULL;
- } else {
- state->bp = next_bp;
- state->regs = NULL;
- }
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
if (state->task != current)
goto the_end;
+ /*
+ * Don't warn if the unwinder got lost due to an interrupt in entry
+ * code or in the C handler before the first frame pointer got set up:
+ */
+ if (state->got_irq && in_entry_code(state->ip))
+ goto the_end;
+ if (state->regs &&
+ state->regs->sp >= (unsigned long)last_aligned_frame(state) &&
+ state->regs->sp < (unsigned long)task_pt_regs(state->task))
+ 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",
state->regs, state->task->comm,
- state->task->pid, next_frame);
- unwind_dump(state, (unsigned long *)state->regs);
+ state->task->pid, next_bp);
+ unwind_dump(state);
} else {
printk_deferred_once(KERN_WARNING
"WARNING: kernel stack frame pointer at %p in %s:%d has bad value %p\n",
state->bp, state->task->comm,
- state->task->pid, next_frame);
- unwind_dump(state, state->bp);
+ state->task->pid, next_bp);
+ unwind_dump(state);
}
the_end:
state->stack_info.type = STACK_TYPE_UNKNOWN;
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame)
{
- unsigned long *bp, *frame;
- size_t len;
+ unsigned long *bp;
memset(state, 0, sizeof(*state));
state->task = task;
+ state->got_irq = (regs);
- /* don't even attempt to start from user mode regs */
+ /* Don't even attempt to start from user mode regs: */
if (regs && user_mode(regs)) {
state->stack_info.type = STACK_TYPE_UNKNOWN;
return;
}
- /* set up the starting stack frame */
bp = get_frame_pointer(task, regs);
- regs = decode_frame_pointer(bp);
- if (regs) {
- state->regs = regs;
- frame = (unsigned long *)regs;
- len = sizeof(*regs);
- } else {
- state->bp = bp;
- frame = bp;
- len = FRAME_HEADER_SIZE;
- }
- /* initialize stack info and make sure the frame data is accessible */
- get_stack_info(frame, state->task, &state->stack_info,
+ /* Initialize stack info and make sure the frame data is accessible: */
+ get_stack_info(bp, state->task, &state->stack_info,
&state->stack_mask);
- update_stack_state(state, frame, len);
+ update_stack_state(state, bp);
/*
* The caller can provide the address of the first frame directly
projects / karo-tx-linux.git / blobdiff