kernel message buffer/log. Its off by default and can be switched on in the
kernel configuration on build time, be set as a variable in ddb and be set
using sysctl.
This adds the sysctl value
ddb.tee_msgbuf = 0
by default.
The functionality is especially added and aimed for developers who are not
blessed with a serial console and wish to keep all their ddb output in the
log. Specifying /l as a modifier to some selected commands will also put
the output in the log but not all commands provide one nor has the same
meaning for all commands.
This feature could in the future also be implemented as an ddb command but
that could lead to more bloat allthough maybe easier for non developpers to
use when mailing their backtraces from kernel crashes.
kernel config option) that controls whether the kernel dumps to the
dump device on panic. Dumps can still be forced via the ``sync''
command from ddb. Defaults to ``on''.
the number of times it is called. This allows subsystems to report
the number of errors that occurred during a quiet/silent subsystem
startup. aprint_get_error_count() reports this count and resets it
to 0.
Also add printf_nolog(), which is like printf(), but prevents the
output from hitting the system log.
autoconfiguration messages:
aprint_normal: Send to console unless AB_QUIET. Always goes to the log.
aprint_naive: Send to console only if AB_QUIET. Never goes to the log.
aprint_verbose: Send to console only if AB_VERBOSE. Always goes to the log.
aprint_debug: Send to console and log only if AB_DEBUG.
API inspired by the same routines in BSD/OS.
Will be used to address kern/5155.
<sys/kprintf.h> header file. This allows subsystems that need
printf semantics other than what are provided by the standard
kernel printf routines to implement exactly what they want.
use that to inform about way to raise current limit when we reach maximum
number of processes, descriptors or vnodes
XXX hopefully I catched all users of tablefull()
- add a new global variable, doing_shutdown, which is nonzero if
vfs_shutdown() or panic() have been called.
- in panic, set RB_NOSYNC if doing_shutdown is already set on entry
so we don't reenter vfs_shutdown if we panic'ed there.
- in vfs_shutdown, don't use proc0's process for sys_sync unless
curproc is NULL.
- in lockmgr, attribute successful locks to proc0 if doing_shutdown
&& curproc==NULL, and panic if we can't get the lock right away; avoids the
spurious lockmgr DIAGNOSTIC panic from the ddb reboot command.
- in subr_pool, deal with curproc==NULL in the doing_shutdown case.
- in mfs_strategy, bitbucket writes if doing_shutdown, so we don't
wedge waiting for the mfs process.
- in ltsleep, treat ((curproc == NULL) && doing_shutdown) like the
panicstr case.
Appears to fix: kern/9239, kern/10187, kern/9367.
May also fix kern/10122.
db_stack_trace_print(__builtin_frame_address(0),...), to printf() the
stack trace to the message bufffer and console. Idea from SunOS/Solaris.
Useful when dumping fails.
locking primitive directly to lock it, since those will never attempt
to call printf() to display debugging information (and thus deadlock
on recursion into the kprintf_slock).
DDB_ONPANIC. Lets user ignore breaks but enter DDB on panic. Intended
for machines where debug on panic is useful, but DDB entry is not,
(public-access console, or terminal-servers which send spurious breaks)
Add new ddb hook, console_debugger(), which decides whether or not to
ignore console ddb requests. Console drivers should be updated to call
console_debugger(), not Debugger(), in response to serial-console
break or ddb keyboard sequence.
