Hi,
Here is v2 of a series to remove the safe buffers. v1 can be
found here [0]. The safe buffers are no longer needed because
messages can be stored directly into the log buffer from any
context.
However, the safe buffers also provided a form of recursion
protection. For that reason, explicit recursion protection is
also implemented for this series.
And finally, with the removal of the safe buffers, there is no
need for extra NMI enter/exit tracking. So this is also removed
(which includes removing config option CONFIG_PRINTK_NMI).
This series is based on the printk-rework branch of
printk/linux.git:
commit acebb5597ff1 ("kernel/printk.c: Fixed mundane typos")
Changes since v1:
- remove the printk nmi enter/exit tracking
- remove CONFIG_PRINTK_NMI config option
- use in_nmi() to detect NMI context
- remove unused printk_safe_enter/exit macros
- after switching to the dynamic buffer, copy over NMI records
that may have arrived during the switch window
- use local_irq_*() instead of printk_safe_*() for console
spinning
- use separate variables rather than arrays for the per-cpu
recursion tracking
- make @syslog_lock a mutex instead of a spin_lock
- close the wait-read window for SYSLOG_ACTION_READ
- adjust various comments and commit messages as requested
John Ogness
[0] https://lore.kernel.org/lkml/20210316233326.10778-1-john.ogness@xxxxxxxxxxxxx
John Ogness (5):
printk: track/limit recursion
printk: remove safe buffers
printk: remove NMI tracking
printk: convert @syslog_lock to mutex
printk: syslog: close window between wait and read
arch/arm/kernel/smp.c | 2 -
arch/powerpc/kernel/traps.c | 1 -
arch/powerpc/kernel/watchdog.c | 5 -
arch/powerpc/kexec/crash.c | 3 -
include/linux/hardirq.h | 2 -
include/linux/printk.h | 22 --
init/Kconfig | 5 -
kernel/kexec_core.c | 1 -
kernel/panic.c | 3 -
kernel/printk/internal.h | 23 ---
kernel/printk/printk.c | 281 +++++++++++++++----------
kernel/printk/printk_safe.c | 362 +--------------------------------
kernel/trace/trace.c | 2 -
lib/nmi_backtrace.c | 6 -
14 files changed, 171 insertions(+), 547 deletions(-)
--
2.20.1
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