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authorDongdong Deng <dongdong.deng@windriver.com>2010-08-30 21:06:00 -0500
committerJason Wessel <jason.wessel@windriver.com>2010-10-29 13:14:41 -0500
commit4dacd5c073150cd78dfb6004cbfa71986f0258a4 (patch)
tree7da8bd47cc31480a44b579d37290339021d11162
parentd7ba979d45272385ce0fdf141d922e61ff48e07b (diff)
kgdbts: prevent re-entry to kgdbts before it unregisters
The "kgdb_connected" variable of debug_core just indicates whether or not kgdbts is connected to the debug_core. It does not completely prevent a script from trying invoke kgdbts again and possibly crashing the system (see Call Trace below). The configured variable in kgtbts can be used instead of kgdb_connected instead of kgdb_connected. The cleanup_kgdbts() can also be removed because there is no possible way to build kgdbts as a kernel module that you could unload with rmmod. Call Trace: ----------------------------------------------------------------- root:/$ echo kgdbts=V1S1000 > /sys/module/kgdbts/parameters/kgdbts kgdb: Unregistered I/O driver kgdbts, debugger disabled. ------------[ cut here ]------------ WARNING: at kernel/debug/debug_core.c:1002 kgdb_unregister_io_module+0xec/0x100() Hardware name: Moon Creek platform Modules linked in: Pid: 664, comm: sh Not tainted 2.6.34.1-WR4.0.0.0_standard #58 Call Trace: [<c103b1ed>] warn_slowpath_common+0x6d/0xa0 [<c1079fdc>] ? kgdb_unregister_io_module+0xec/0x100 [<c1079fdc>] ? kgdb_unregister_io_module+0xec/0x100 [<c10544e0>] ? param_attr_store+0x0/0x20 [<c103b235>] warn_slowpath_null+0x15/0x20 [<c1079fdc>] kgdb_unregister_io_module+0xec/0x100 [<c124e4ea>] cleanup_kgdbts+0x1a/0x20 [<c124eced>] param_set_kgdbts_var+0x6d/0xb0 [<c124ec80>] ? param_set_kgdbts_var+0x0/0xb0 [<c10544f7>] param_attr_store+0x17/0x20 [<c105457c>] module_attr_store+0x2c/0x40 [<c111fe84>] sysfs_write_file+0x94/0xf0 [<c10d42f6>] vfs_write+0x96/0x130 [<c111fdf0>] ? sysfs_write_file+0x0/0xf0 [<c10d44d6>] sys_write+0x46/0xd0 [<c13bf329>] system_call_done+0x0/0x4 ---[ end trace 4eb028c6ee43154c ]--- kgdb: Unregistered I/O driver kgdbts, debugger disabled. ----------------------------------------------------------------- [jason.wessel@windriver.com: remove cleanup_kgdbts() ] Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
-rw-r--r--drivers/misc/kgdbts.c16
1 files changed, 2 insertions, 14 deletions
diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
index 72450237a0f4..59c118c19a91 100644
--- a/drivers/misc/kgdbts.c
+++ b/drivers/misc/kgdbts.c
@@ -1044,12 +1044,6 @@ static int __init init_kgdbts(void)
return configure_kgdbts();
}
-static void cleanup_kgdbts(void)
-{
- if (configured == 1)
- kgdb_unregister_io_module(&kgdbts_io_ops);
-}
-
static int kgdbts_get_char(void)
{
int val = 0;
@@ -1081,10 +1075,8 @@ static int param_set_kgdbts_var(const char *kmessage, struct kernel_param *kp)
return 0;
}
- if (kgdb_connected) {
- printk(KERN_ERR
- "kgdbts: Cannot reconfigure while KGDB is connected.\n");
-
+ if (configured == 1) {
+ printk(KERN_ERR "kgdbts: ERROR: Already configured and running.\n");
return -EBUSY;
}
@@ -1093,9 +1085,6 @@ static int param_set_kgdbts_var(const char *kmessage, struct kernel_param *kp)
if (config[len - 1] == '\n')
config[len - 1] = '\0';
- if (configured == 1)
- cleanup_kgdbts();
-
/* Go and configure with the new params. */
return configure_kgdbts();
}
@@ -1123,7 +1112,6 @@ static struct kgdb_io kgdbts_io_ops = {
};
module_init(init_kgdbts);
-module_exit(cleanup_kgdbts);
module_param_call(kgdbts, param_set_kgdbts_var, param_get_string, &kps, 0644);
MODULE_PARM_DESC(kgdbts, "<A|V1|V2>[F#|S#][N#]");
MODULE_DESCRIPTION("KGDB Test Suite");