1 files changed, 19 insertions, 33 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index ab3ffc5b3b64..53d9a9ec88e6 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -39,16 +39,11 @@
 #include <linux/syslog.h>
 #include <linux/cpu.h>
 #include <linux/notifier.h>
+#include <linux/rculist.h>
 
 #include <asm/uaccess.h>
 
 /*
- * for_each_console() allows you to iterate on each console
- */
-#define for_each_console(con) \
-        for (con = console_drivers; con != NULL; con = con->next)
-
-/*
  * Architectures can override it:
  */
 void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...)
@@ -279,12 +274,12 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
          * at open time.
          */
         if (type == SYSLOG_ACTION_OPEN || !from_file) {
-                if (dmesg_restrict && !capable(CAP_SYS_ADMIN))
-                        return -EPERM;
+                if (dmesg_restrict && !capable(CAP_SYSLOG))
+                        goto warn; /* switch to return -EPERM after 2.6.39 */
                 if ((type != SYSLOG_ACTION_READ_ALL &&
                      type != SYSLOG_ACTION_SIZE_BUFFER) &&
-                    !capable(CAP_SYS_ADMIN))
-                        return -EPERM;
+                    !capable(CAP_SYSLOG))
+                        goto warn; /* switch to return -EPERM after 2.6.39 */
         }
 
         error = security_syslog(type);
@@ -428,6 +423,12 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
         }
 out:
         return error;
+warn:
+        /* remove after 2.6.39 */
+        if (capable(CAP_SYS_ADMIN))
+                WARN_ONCE(1, "Attempt to access syslog with CAP_SYS_ADMIN "
+                  "but no CAP_SYSLOG (deprecated and denied).\n");
+        return -EPERM;
 }
 
 SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
@@ -1359,6 +1360,7 @@ void register_console(struct console *newcon)
                 spin_unlock_irqrestore(&logbuf_lock, flags);
         }
         release_console_sem();
+        console_sysfs_notify();
 
         /*
          * By unregistering the bootconsoles after we enable the real console
@@ -1417,6 +1419,7 @@ int unregister_console(struct console *console)
                 console_drivers->flags |= CON_CONSDEV;
 
         release_console_sem();
+        console_sysfs_notify();
         return res;
 }
 EXPORT_SYMBOL(unregister_console);
@@ -1500,7 +1503,7 @@ int kmsg_dump_register(struct kmsg_dumper *dumper)
         /* Don't allow registering multiple times */
         if (!dumper->registered) {
                 dumper->registered = 1;
-                list_add_tail(&dumper->list, &dump_list);
+                list_add_tail_rcu(&dumper->list, &dump_list);
                 err = 0;
         }
         spin_unlock_irqrestore(&dump_list_lock, flags);
@@ -1524,29 +1527,16 @@ int kmsg_dump_unregister(struct kmsg_dumper *dumper)
         spin_lock_irqsave(&dump_list_lock, flags);
         if (dumper->registered) {
                 dumper->registered = 0;
-                list_del(&dumper->list);
+                list_del_rcu(&dumper->list);
                 err = 0;
         }
         spin_unlock_irqrestore(&dump_list_lock, flags);
+        synchronize_rcu();
 
         return err;
 }
 EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
 
-static const char * const kmsg_reasons[] = {
-        [KMSG_DUMP_OOPS]        = "oops",
-        [KMSG_DUMP_PANIC]       = "panic",
-        [KMSG_DUMP_KEXEC]       = "kexec",
-};
-
-static const char *kmsg_to_str(enum kmsg_dump_reason reason)
-{
-        if (reason >= ARRAY_SIZE(kmsg_reasons) || reason < 0)
-                return "unknown";
-
-        return kmsg_reasons[reason];
-}
-
 /**
  * kmsg_dump - dump kernel log to kernel message dumpers.
  * @reason: the reason (oops, panic etc) for dumping
@@ -1585,13 +1575,9 @@ void kmsg_dump(enum kmsg_dump_reason reason)
                 l2 = chars;
         }
 
-        if (!spin_trylock_irqsave(&dump_list_lock, flags)) {
-                printk(KERN_ERR "dump_kmsg: dump list lock is held during %s, skipping dump\n",
-                                kmsg_to_str(reason));
-                return;
-        }
-        list_for_each_entry(dumper, &dump_list, list)
+        rcu_read_lock();
+        list_for_each_entry_rcu(dumper, &dump_list, list)
                 dumper->dump(dumper, reason, s1, l1, s2, l2);
-        spin_unlock_irqrestore(&dump_list_lock, flags);
+        rcu_read_unlock();
 }
 #endif