Commit-ID:  25e39e32b0a3f99b9db320605f20f91d425b6a65
Gitweb:     https://git.kernel.org/tip/25e39e32b0a3f99b9db320605f20f91d425b6a65
Author:     Thomas Gleixner <[email protected]>
AuthorDate: Thu, 25 Apr 2019 11:45:18 +0200
Committer:  Thomas Gleixner <[email protected]>
CommitDate: Mon, 29 Apr 2019 12:37:56 +0200

livepatch: Simplify stack trace retrieval

Replace the indirection through struct stack_trace by using the storage
array based interfaces.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
Acked-by: Miroslav Benes <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: [email protected]
Cc: David Rientjes <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: [email protected]
Cc: Mike Rapoport <[email protected]>
Cc: Akinobu Mita <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: [email protected]
Cc: Robin Murphy <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Johannes Thumshirn <[email protected]>
Cc: David Sterba <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Josef Bacik <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Mike Snitzer <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Cc: Joonas Lahtinen <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: [email protected]
Cc: David Airlie <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Tom Zanussi <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]

---
 kernel/livepatch/transition.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index 9c89ae8b337a..c53370d596be 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -202,15 +202,15 @@ void klp_update_patch_state(struct task_struct *task)
  * Determine whether the given stack trace includes any references to a
  * to-be-patched or to-be-unpatched function.
  */
-static int klp_check_stack_func(struct klp_func *func,
-                               struct stack_trace *trace)
+static int klp_check_stack_func(struct klp_func *func, unsigned long *entries,
+                               unsigned int nr_entries)
 {
        unsigned long func_addr, func_size, address;
        struct klp_ops *ops;
        int i;
 
-       for (i = 0; i < trace->nr_entries; i++) {
-               address = trace->entries[i];
+       for (i = 0; i < nr_entries; i++) {
+               address = entries[i];
 
                if (klp_target_state == KLP_UNPATCHED) {
                         /*
@@ -254,29 +254,25 @@ static int klp_check_stack_func(struct klp_func *func,
 static int klp_check_stack(struct task_struct *task, char *err_buf)
 {
        static unsigned long entries[MAX_STACK_ENTRIES];
-       struct stack_trace trace;
        struct klp_object *obj;
        struct klp_func *func;
-       int ret;
+       int ret, nr_entries;
 
-       trace.skip = 0;
-       trace.nr_entries = 0;
-       trace.max_entries = MAX_STACK_ENTRIES;
-       trace.entries = entries;
-       ret = save_stack_trace_tsk_reliable(task, &trace);
+       ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries));
        WARN_ON_ONCE(ret == -ENOSYS);
-       if (ret) {
+       if (ret < 0) {
                snprintf(err_buf, STACK_ERR_BUF_SIZE,
                         "%s: %s:%d has an unreliable stack\n",
                         __func__, task->comm, task->pid);
                return ret;
        }
+       nr_entries = ret;
 
        klp_for_each_object(klp_transition_patch, obj) {
                if (!obj->patched)
                        continue;
                klp_for_each_func(obj, func) {
-                       ret = klp_check_stack_func(func, &trace);
+                       ret = klp_check_stack_func(func, entries, nr_entries);
                        if (ret) {
                                snprintf(err_buf, STACK_ERR_BUF_SIZE,
                                         "%s: %s:%d is sleeping on function 
%s\n",

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