LU-14099 build: Fix for unconfigured arch_stackwalk

On aarch64 CONFIG_ARCH_STACKWALK is not defined and
print_stack_trace is not available.

Replace print_stack_trace with an open-coded variant
using %pB introduced in Linux v2.6.38-6557-g0f77a8d37825

This also fixes the symbols lookup of stack_trace_save_tsk
using kallsyms at module init time over the use of
symbol_get.

HPE-bug-id: LUS-9518
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I04c3a0a84bb1a05d813a90502d1ed0f5bb2e33ab
Reviewed-on: https://review.whamcloud.com/40503
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Tested-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/libcfs/include/libcfs/libcfs_debug.h b/libcfs/include/libcfs/libcfs_debug.h
index f3a328c..cfbfafe 100644 (file)
--- a/libcfs/include/libcfs/libcfs_debug.h
+++ b/libcfs/include/libcfs/libcfs_debug.h
@@ -298,4 +298,6 @@ int cfs_trace_copyout_string(char __user *usr_buffer, int usr_buffer_nob,
 
 #define LIBCFS_DEBUG_FILE_PATH_DEFAULT "/tmp/lustre-log"
 
+void cfs_debug_init(void);
+
 #endif /* __LIBCFS_DEBUG_H__ */

diff --git a/libcfs/libcfs/debug.c b/libcfs/libcfs/debug.c
index 512f64f..b6d8b42 100644 (file)
--- a/libcfs/libcfs/debug.c
+++ b/libcfs/libcfs/debug.c
@@ -43,6 +43,7 @@
 #include <linux/kthread.h>
 #include <linux/stacktrace.h>
 #include <linux/utsname.h>
+#include <linux/kallsyms.h>
 #include "tracefile.h"
 
 static char debug_file_name[1024];
@@ -486,6 +487,18 @@ do {                                                                              \
 } while (0)
 #endif
 
+static void cfs_print_stack_trace(unsigned long *entries, unsigned int nr)
+{
+       unsigned int i;
+
+       /* Prefer %pB for backtraced symbolic names since it was added in:
+        * Linux v2.6.38-6557-g0f77a8d37825
+        * vsprintf: Introduce %pB format specifier
+        */
+       for (i = 0; i < nr; i++)
+               pr_info("[<0>] %pB\n", (void *)entries[i]);
+}
+
 #define MAX_ST_ENTRIES 100
 static DEFINE_SPINLOCK(st_lock);
 
@@ -501,15 +514,20 @@ typedef unsigned int (stack_trace_save_tsk_t)(struct task_struct *task,
 static stack_trace_save_tsk_t *task_dump_stack;
 #endif
 
-static void libcfs_call_trace(struct task_struct *tsk)
+void __init cfs_debug_init(void)
 {
 #ifdef CONFIG_ARCH_STACKWALK
-       static unsigned long entries[MAX_ST_ENTRIES];
-       unsigned int i, nr_entries;
+       task_dump_stack = (void *)
+                       kallsyms_lookup_name("stack_trace_save_tsk");
 
-       if (!task_dump_stack)
-               task_dump_stack = (stack_trace_save_tsk_t *)
-                                 symbol_get("stack_trace_save_tsk");
+#endif
+}
+
+static void libcfs_call_trace(struct task_struct *tsk)
+{
+       static unsigned long entries[MAX_ST_ENTRIES];
+#ifdef CONFIG_ARCH_STACKWALK
+       unsigned int nr_entries;
 
        spin_lock(&st_lock);
        pr_info("Pid: %d, comm: %.20s %s %s\n", tsk->pid, tsk->comm,
@@ -517,13 +535,11 @@ static void libcfs_call_trace(struct task_struct *tsk)
        pr_info("Call Trace TBD:\n");
        if (task_dump_stack) {
                nr_entries = task_dump_stack(tsk, entries, MAX_ST_ENTRIES, 0);
-               for (i = 0; i < nr_entries; i++)
-                       pr_info("[<0>] %pB\n", (void *)entries[i]);
+               cfs_print_stack_trace(entries, nr_entries);
        }
        spin_unlock(&st_lock);
 #else
        struct stack_trace trace;
-       static unsigned long entries[MAX_ST_ENTRIES];
 
        trace.nr_entries = 0;
        trace.max_entries = MAX_ST_ENTRIES;
@@ -535,7 +551,7 @@ static void libcfs_call_trace(struct task_struct *tsk)
                init_utsname()->release, init_utsname()->version);
        pr_info("Call Trace:\n");
        save_stack_trace_tsk(tsk, &trace);
-       print_stack_trace(&trace, 0);
+       cfs_print_stack_trace(trace.entries, trace.nr_entries);
        spin_unlock(&st_lock);
 #endif
 }

diff --git a/libcfs/libcfs/module.c b/libcfs/libcfs/module.c
index 51a3ce4..583a1fb 100644 (file)
--- a/libcfs/libcfs/module.c
+++ b/libcfs/libcfs/module.c
@@ -729,6 +729,8 @@ static int __init libcfs_init(void)
                return (rc);
        }
 
+       cfs_debug_init();
+
        rc = cfs_cpu_init();
        if (rc != 0)
                goto cleanup_debug;