linux/kernel/printk, branch v4.0

console: Fix console name size mismatch

2015-03-07T02:39:55Z

commit 6ae9200f2cab7 ("enlarge console.name") increased the storage for the console name to 16 bytes, but not the corresponding struct console_cmdline::name storage. Console names longer than 8 bytes cause read beyond end-of-string and failure to match console; I'm not sure if there are other unexpected consequences. Cc: # 2.6.22+ Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

Merge tag 'for_linux-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

2015-02-20T23:13:29Z

Pull kgdb/kdb updates from Jason Wessel: "KGDB/KDB New: - KDB: improved searching - No longer enter debug core on panic if panic timeout is set KGDB/KDB regressions / cleanups - fix pdf doc build errors - prevent junk characters on kdb console from printk levels" * tag 'for_linux-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb: kgdb, docs: Fix pdfdocs build errors debug: prevent entering debug mode on panic/exception. kdb: Const qualifier for kdb_getstr's prompt argument kdb: Provide forward search at more prompt kdb: Fix a prompt management bug when using | grep kdb: Remove stack dump when entering kgdb due to NMI kdb: Avoid printing KERN_ levels to consoles kdb: Fix off by one error in kdb_cpu() kdb: fix incorrect counts in KDB summary command output

kdb: Avoid printing KERN_ levels to consoles

2015-02-19T18:39:02Z

Currently when kdb traps printk messages then the raw log level prefix (consisting of '\001' followed by a numeral) does not get stripped off before the message is issued to the various I/O handlers supported by kdb. This causes annoying visual noise as well as causing problems grepping for ^. It is also a change of behaviour compared to normal usage of printk() usage. For example -h ends up with different output to that of kdb's "sr h". This patch addresses the problem by stripping log levels from messages before they are issued to the I/O handlers. printk() which can also act as an i/o handler in some cases is special cased; if the caller provided a log level then the prefix will be preserved when sent to printk(). The addition of non-printable characters to the output of kdb commands is a regression, albeit and extremely elderly one, introduced by commit 04d2c8c83d0e ("printk: convert the format for KERN_ to a 2 byte pattern"). Note also that this patch does *not* restore the original behaviour from v3.5. Instead it makes printk() from within a kdb command display the message without any prefix (i.e. like printk() normally does). Signed-off-by: Daniel Thompson Cc: Joe Perches Cc: stable@vger.kernel.org Signed-off-by: Jason Wessel

printk: correct timeout comment, neaten MODULE_PARM_DESC

2015-02-13T02:54:13Z

Neaten the MODULE_PARAM_DESC message. Use 30 seconds in the comment for the zap console locks timeout. Signed-off-by: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'trace-seq-buf-3.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2014-12-13T22:04:41Z

Pull tracing fixlet from Steven Rostedt: "Remove unnecessary preempt_disable in printk()" * tag 'trace-seq-buf-3.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: printk: Do not disable preemption for accessing printk_func

printk: Do not disable preemption for accessing printk_func

2014-12-11T14:12:01Z

As printk_func will either be the default function, or a per_cpu function for the current CPU, there's no reason to disable preemption to access it from printk. That's because if the printk_func is not the default then the caller had better disabled preemption as they were the one to change it. Link: http://lkml.kernel.org/r/CA+55aFz5-_LKW4JHEBoWinN9_ouNcGRWAF2FUA35u46FRN-Kxw@mail.gmail.com Suggested-by: Linus Torvalds Signed-off-by: Steven Rostedt

Merge tag 'trace-seq-buf-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2014-12-11T04:35:41Z

Pull nmi-safe seq_buf printk update from Steven Rostedt: "This code is a fork from the trace-3.19 pull as it needed the trace_seq clean ups from that branch. This code solves the issue of performing stack dumps from NMI context. The issue is that printk() is not safe from NMI context as if the NMI were to trigger when a printk() was being performed, the NMI could deadlock from the printk() internal locks. This has been seen in practice. With lots of review from Petr Mladek, this code went through several iterations, and we feel that it is now at a point of quality to be accepted into mainline. Here's what is contained in this patch set: - Creates a "seq_buf" generic buffer utility that allows a descriptor to be passed around where functions can write their own "printk()" formatted strings into it. The generic version was pulled out of the trace_seq() code that was made specifically for tracing. - The seq_buf code was change to model the seq_file code. I have a patch (not included for 3.19) that converts the seq_file.c code over to use seq_buf.c like the trace_seq.c code does. This was done to make sure that seq_buf.c is compatible with seq_file.c. I may try to get that patch in for 3.20. - The seq_buf.c file was moved to lib/ to remove it from being dependent on CONFIG_TRACING. - The printk() was updated to allow for a per_cpu "override" of the internal calls. That is, instead of writing to the console, a call to printk() may do something else. This made it easier to allow the NMI to change what printk() does in order to call dump_stack() without needing to update that code as well. - Finally, the dump_stack from all CPUs via NMI code was converted to use the seq_buf code. The caller to trigger the NMI code would wait till all the NMIs finished, and then it would print the seq_buf data to the console safely from a non NMI context One added bonus is that this code also makes the NMI dump stack work on PREEMPT_RT kernels. As printk() includes sleeping locks on PREEMPT_RT, printk() only writes to console if the console does not use any rt_mutex converted spin locks. Which a lot do" * tag 'trace-seq-buf-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: x86/nmi: Fix use of unallocated cpumask_var_t printk/percpu: Define printk_func when printk is not defined x86/nmi: Perform a safe NMI stack trace on all CPUs printk: Add per_cpu printk func to allow printk to be diverted seq_buf: Move the seq_buf code to lib/ seq-buf: Make seq_buf_bprintf() conditional on CONFIG_BINARY_PRINTF tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions tracing: Have seq_buf use full buffer seq_buf: Add seq_buf_can_fit() helper function tracing: Add paranoid size check in trace_printk_seq() tracing: Use trace_seq_used() and seq_buf_used() instead of len tracing: Clean up tracing_fill_pipe_page() seq_buf: Create seq_buf_used() to find out how much was written tracing: Add a seq_buf_clear() helper and clear len and readpos in init tracing: Convert seq_buf fields to be like seq_file fields tracing: Convert seq_buf_path() to be like seq_path() tracing: Create seq_buf layer in trace_seq

Merge branch 'akpm' (patchbomb from Andrew)

2014-12-11T02:34:42Z

Merge first patchbomb from Andrew Morton: - a few minor cifs fixes - dma-debug upadtes - ocfs2 - slab - about half of MM - procfs - kernel/exit.c - panic.c tweaks - printk upates - lib/ updates - checkpatch updates - fs/binfmt updates - the drivers/rtc tree - nilfs - kmod fixes - more kernel/exit.c - various other misc tweaks and fixes * emailed patches from Andrew Morton : (190 commits) exit: pidns: fix/update the comments in zap_pid_ns_processes() exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting exit: exit_notify: re-use "dead" list to autoreap current exit: reparent: call forget_original_parent() under tasklist_lock exit: reparent: avoid find_new_reaper() if no children exit: reparent: introduce find_alive_thread() exit: reparent: introduce find_child_reaper() exit: reparent: document the ->has_child_subreaper checks exit: reparent: s/while_each_thread/for_each_thread/ in find_new_reaper() exit: reparent: fix the cross-namespace PR_SET_CHILD_SUBREAPER reparenting exit: reparent: fix the dead-parent PR_SET_CHILD_SUBREAPER reparenting exit: proc: don't try to flush /proc/tgid/task/tgid exit: release_task: fix the comment about group leader accounting exit: wait: drop tasklist_lock before psig->c* accounting exit: wait: don't use zombie->real_parent exit: wait: cleanup the ptrace_reparented() checks usermodehelper: kill the kmod_thread_locker logic usermodehelper: don't use CLONE_VFORK for ____call_usermodehelper() fs/hfs/catalog.c: fix comparison bug in hfs_cat_keycmp nilfs2: fix the nilfs_iget() vs. nilfs_new_inode() races ...

printk: drop logbuf_cpu volatile qualifier

2014-12-11T01:41:11Z

Pranith Kumar posted a patch in which removed the "volatile" qualifier for the "logbuf_cpu" variable in vprintk_emit(). https://lkml.org/lkml/2014/11/13/894 In his patch, he used ACCESS_ONCE() for all references to that symbol to provide whatever protection was intended. There was some discussion that followed, and in the end Steven Rostedt concluded that not only was "volatile" not needed, neither was it required to use ACCESS_ONCE(). I offered an elaborate description that concluded Steven was right, and Pranith asked me to submit an alternative patch. And this is it. The basic reason "volatile" is not needed is that "logbuf_cpu" has static storage duration, and vprintk_emit() is an exported interface. This means that the value of logbuf_cpu must be read from memory the first time it is used in a particular call of vprintk_emit(). The variable's value is read only once in that function, when it's read it'll be the copy from memory (or cache). In addition, the value of "logbuf_cpu" is only ever written under protection of a spinlock. So the value that is read is the "real" value (and not an out-of-date cached one). If its value is not UINT_MAX, it is the current CPU's processor id, and it will have been last written by the running CPU. Signed-off-by: Alex Elder Reported-by: Pranith Kumar Suggested-by: Steven Rostedt Reviewed-by: Jan Kara Cc: Petr Mladek Cc: Luis R. Rodriguez Cc: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

printk: add and use LOGLEVEL_ defines for KERN_ equivalents

2014-12-11T01:41:11Z

Use #defines instead of magic values. Signed-off-by: Joe Perches Acked-by: Greg Kroah-Hartman Cc: Jason Baron Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds