*/
struct console_cmdline
{
- char name[8]; /* Name of the driver */
+ char name[16]; /* Name of the driver */
int index; /* Minor dev. to use */
char *options; /* Options for the driver */
#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
log_next_seq++;
}
+#ifdef CONFIG_SECURITY_DMESG_RESTRICT
+int dmesg_restrict = 1;
+#else
+int dmesg_restrict;
+#endif
+
+static int syslog_action_restricted(int type)
+{
+ if (dmesg_restrict)
+ return 1;
+ /*
+ * Unless restricted, we allow "read all" and "get buffer size"
+ * for everybody.
+ */
+ return type != SYSLOG_ACTION_READ_ALL &&
+ type != SYSLOG_ACTION_SIZE_BUFFER;
+}
+
+static int check_syslog_permissions(int type, bool from_file)
+{
+ /*
+ * If this is from /proc/kmsg and we've already opened it, then we've
+ * already done the capabilities checks at open time.
+ */
+ if (from_file && type != SYSLOG_ACTION_OPEN)
+ return 0;
+
+ if (syslog_action_restricted(type)) {
+ if (capable(CAP_SYSLOG))
+ return 0;
+ /*
+ * For historical reasons, accept CAP_SYS_ADMIN too, with
+ * a warning.
+ */
+ if (capable(CAP_SYS_ADMIN)) {
+ pr_warn_once("%s (%d): Attempt to access syslog with "
+ "CAP_SYS_ADMIN but no CAP_SYSLOG "
+ "(deprecated).\n",
+ current->comm, task_pid_nr(current));
+ return 0;
+ }
+ return -EPERM;
+ }
+ return security_syslog(type);
+}
+
+
/* /dev/kmsg - userspace message inject/listen interface */
struct devkmsg_user {
u64 seq;
if ((file->f_flags & O_ACCMODE) == O_WRONLY)
return 0;
- err = security_syslog(SYSLOG_ACTION_READ_ALL);
+ err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
+ SYSLOG_FROM_READER);
if (err)
return err;
}
#endif
-#ifdef CONFIG_SECURITY_DMESG_RESTRICT
-int dmesg_restrict = 1;
-#else
-int dmesg_restrict;
-#endif
-
-static int syslog_action_restricted(int type)
-{
- if (dmesg_restrict)
- return 1;
- /* Unless restricted, we allow "read all" and "get buffer size" for everybody */
- return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER;
-}
-
-static int check_syslog_permissions(int type, bool from_file)
-{
- /*
- * If this is from /proc/kmsg and we've already opened it, then we've
- * already done the capabilities checks at open time.
- */
- if (from_file && type != SYSLOG_ACTION_OPEN)
- return 0;
-
- if (syslog_action_restricted(type)) {
- if (capable(CAP_SYSLOG))
- return 0;
- /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */
- if (capable(CAP_SYS_ADMIN)) {
- printk_once(KERN_WARNING "%s (%d): "
- "Attempt to access syslog with CAP_SYS_ADMIN "
- "but no CAP_SYSLOG (deprecated).\n",
- current->comm, task_pid_nr(current));
- return 0;
- }
- return -EPERM;
- }
- return 0;
-}
-
#if defined(CONFIG_PRINTK_TIME)
static bool printk_time = 1;
#else
SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
{
- return do_syslog(type, buf, len, SYSLOG_FROM_CALL);
+ return do_syslog(type, buf, len, SYSLOG_FROM_READER);
}
/*
}
}
logbuf_cpu = UINT_MAX;
+ raw_spin_unlock(&logbuf_lock);
if (wake)
up(&console_sem);
- raw_spin_unlock(&logbuf_lock);
return retval;
}
static u64 seen_seq;
unsigned long flags;
bool wake_klogd = false;
- bool retry;
+ bool do_cond_resched, retry;
if (console_suspended) {
up(&console_sem);
return;
}
+ /*
+ * Console drivers are called under logbuf_lock, so
+ * @console_may_schedule should be cleared before; however, we may
+ * end up dumping a lot of lines, for example, if called from
+ * console registration path, and should invoke cond_resched()
+ * between lines if allowable. Not doing so can cause a very long
+ * scheduling stall on a slow console leading to RCU stall and
+ * softlockup warnings which exacerbate the issue with more
+ * messages practically incapacitating the system.
+ */
+ do_cond_resched = console_may_schedule;
console_may_schedule = 0;
/* flush buffered message fragment immediately to console */
call_console_drivers(level, text, len);
start_critical_timings();
local_irq_restore(flags);
+
+ if (do_cond_resched)
+ cond_resched();
}
console_locked = 0;
mutex_release(&console_lock_dep_map, 1, _RET_IP_);
console_unlock();
}
+/**
+ * console_flush_on_panic - flush console content on panic
+ *
+ * Immediately output all pending messages no matter what.
+ */
+void console_flush_on_panic(void)
+{
+ /*
+ * If someone else is holding the console lock, trylock will fail
+ * and may_schedule may be set. Ignore and proceed to unlock so
+ * that messages are flushed out. As this can be called from any
+ * context and we don't want to get preempted while flushing,
+ * ensure may_schedule is cleared.
+ */
+ console_trylock();
+ console_may_schedule = 0;
+ console_unlock();
+}
+
/*
* Return the console tty driver structure and its associated index
*/
*/
for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
i++) {
+ BUILD_BUG_ON(sizeof(console_cmdline[i].name) !=
+ sizeof(newcon->name));
if (strcmp(console_cmdline[i].name, newcon->name) != 0)
continue;
if (newcon->index >= 0 &&
preempt_enable();
}
-int printk_sched(const char *fmt, ...)
+int printk_deferred(const char *fmt, ...)
{
unsigned long flags;
va_list args;
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / blobdiff