misc: tegra-profiler: fix hang up bug for Norrin

[sojka/nv-tegra/linux-3.10.git] / drivers / misc / tegra-profiler / eh_unwind.c

diff --git a/drivers/misc/tegra-profiler/eh_unwind.c b/drivers/misc/tegra-profiler/eh_unwind.c
index d97edfb2c617f1c7e90470efb6604459cfe16aa2..c990b0c284bbce04ce696ebb23d00f8b3ad47c7f 100644 (file)
--- a/drivers/misc/tegra-profiler/eh_unwind.c
+++ b/drivers/misc/tegra-profiler/eh_unwind.c
@@ -152,13 +152,25 @@ validate_mmap_addr(struct quadd_extabs_mmap *mmap,
        return 1;
 }
 
-#define read_user_data(addr, retval)                   \
-({                                                     \
-       long ret;                                       \
-       ret = probe_kernel_address(addr, retval);       \
-       if (ret)                                        \
-               ret = -QUADD_URC_EACCESS;               \
-       ret;                                            \
+/*
+ * TBD: why probe_kernel_address() can lead to random crashes
+ * on 64-bit kernel, and replacing it to __get_user() fixed the issue.
+ */
+#define read_user_data(addr, retval)                           \
+({                                                             \
+       int ret;                                                \
+                                                               \
+       pagefault_disable();                                    \
+       ret = __get_user(retval, addr);                         \
+       pagefault_enable();                                     \
+                                                               \
+       if (ret) {                                              \
+               pr_debug("%s: failed for address: %p\n",        \
+                        __func__, addr);                       \
+               ret = -QUADD_URC_EACCESS;                       \
+       }                                                       \
+                                                               \
+       ret;                                                    \
 })
 
 static inline long