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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-22 17:33:34 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-22 17:33:34 -0800 |
| commit | 7d91de74436a69c2b78a7a72f1e7f97f8b4396fa (patch) | |
| tree | a43e68ae4ebbf0ec98678876d584fb0eb0303274 /init | |
| parent | 6ef192f2259e78e1870c509fbd3040e6752b3b9c (diff) | |
| parent | d9c23523ed98a3acaa0bfd8fef143595d6aa631d (diff) | |
| download | lwn-7d91de74436a69c2b78a7a72f1e7f97f8b4396fa.tar.gz lwn-7d91de74436a69c2b78a7a72f1e7f97f8b4396fa.zip | |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Add Petr Mladek, Sergey Senozhatsky as printk maintainers, and Steven
Rostedt as the printk reviewer. This idea came up after the
discussion about printk issues at Kernel Summit. It was formulated
and discussed at lkml[1].
- Extend a lock-less NMI per-cpu buffers idea to handle recursive
printk() calls by Sergey Senozhatsky[2]. It is the first step in
sanitizing printk as discussed at Kernel Summit.
The change allows to see messages that would normally get ignored or
would cause a deadlock.
Also it allows to enable lockdep in printk(). This already paid off.
The testing in linux-next helped to discover two old problems that
were hidden before[3][4].
- Remove unused parameter by Sergey Senozhatsky. Clean up after a past
change.
[1] http://lkml.kernel.org/r/1481798878-31898-1-git-send-email-pmladek@suse.com
[2] http://lkml.kernel.org/r/20161227141611.940-1-sergey.senozhatsky@gmail.com
[3] http://lkml.kernel.org/r/20170215044332.30449-1-sergey.senozhatsky@gmail.com
[4] http://lkml.kernel.org/r/20170217015932.11898-1-sergey.senozhatsky@gmail.com
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: drop call_console_drivers() unused param
printk: convert the rest to printk-safe
printk: remove zap_locks() function
printk: use printk_safe buffers in printk
printk: report lost messages in printk safe/nmi contexts
printk: always use deferred printk when flush printk_safe lines
printk: introduce per-cpu safe_print seq buffer
printk: rename nmi.c and exported api
printk: use vprintk_func in vprintk()
MAINTAINERS: Add printk maintainers
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 16 | ||||
| -rw-r--r-- | init/main.c | 2 |
2 files changed, 10 insertions, 8 deletions
diff --git a/init/Kconfig b/init/Kconfig index 55bb6fbc294e..483ad679aa37 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -861,17 +861,19 @@ config LOG_CPU_MAX_BUF_SHIFT 13 => 8 KB for each CPU 12 => 4 KB for each CPU -config NMI_LOG_BUF_SHIFT - int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)" +config PRINTK_SAFE_LOG_BUF_SHIFT + int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)" range 10 21 default 13 - depends on PRINTK_NMI + depends on PRINTK help - Select the size of a per-CPU buffer where NMI messages are temporary - stored. They are copied to the main log buffer in a safe context - to avoid a deadlock. The value defines the size as a power of 2. + Select the size of an alternate printk per-CPU buffer where messages + printed from usafe contexts are temporary stored. One example would + be NMI messages, another one - printk recursion. The messages are + copied to the main log buffer in a safe context to avoid a deadlock. + The value defines the size as a power of 2. - NMI messages are rare and limited. The largest one is when + Those messages are rare and limited. The largest one is when a backtrace is printed. It usually fits into 4KB. Select 8KB if you want to be on the safe side. diff --git a/init/main.c b/init/main.c index c8a00f0f10ff..24ea48745061 100644 --- a/init/main.c +++ b/init/main.c @@ -581,7 +581,7 @@ asmlinkage __visible void __init start_kernel(void) timekeeping_init(); time_init(); sched_clock_postinit(); - printk_nmi_init(); + printk_safe_init(); perf_event_init(); profile_init(); call_function_init(); |