diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-27 18:09:44 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-27 18:09:44 -0700 |
commit | 7f3d08b255d1806502e45fe70ca2ba9646eb3aa1 (patch) | |
tree | b05f285f31a37dac5910c40a643c7d38b19dfe3c /arch/um/kernel | |
parent | 916a75965e5236f9e353416a703a0f4c8de2f56c (diff) | |
parent | c8dbea6df351df211216b5f8877b020f21ecf75f (diff) |
Merge tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- Stop synchronizing kernel log buffer readers by logbuf_lock. As a
result, the access to the buffer is fully lockless now.
Note that printk() itself still uses locks because it tries to flush
the messages to the console immediately. Also the per-CPU temporary
buffers are still there because they prevent infinite recursion and
serialize backtraces from NMI. All this is going to change in the
future.
- kmsg_dump API rework and cleanup as a side effect of the logbuf_lock
removal.
- Make bstr_printf() aware that %pf and %pF formats could deference the
given pointer.
- Show also page flags by %pGp format.
- Clarify the documentation for plain pointer printing.
- Do not show no_hash_pointers warning multiple times.
- Update Senozhatsky email address.
- Some clean up.
* tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (24 commits)
lib/vsprintf.c: remove leftover 'f' and 'F' cases from bstr_printf()
printk: clarify the documentation for plain pointer printing
kernel/printk.c: Fixed mundane typos
printk: rename vprintk_func to vprintk
vsprintf: dump full information of page flags in pGp
mm, slub: don't combine pr_err with INFO
mm, slub: use pGp to print page flags
MAINTAINERS: update Senozhatsky email address
lib/vsprintf: do not show no_hash_pointers message multiple times
printk: console: remove unnecessary safe buffer usage
printk: kmsg_dump: remove _nolock() variants
printk: remove logbuf_lock
printk: introduce a kmsg_dump iterator
printk: kmsg_dumper: remove @active field
printk: add syslog_lock
printk: use atomic64_t for devkmsg_user.seq
printk: use seqcount_latch for clear_seq
printk: introduce CONSOLE_LOG_MAX
printk: consolidate kmsg_dump_get_buffer/syslog_print_all code
printk: refactor kmsg_dump_get_buffer()
...
Diffstat (limited to 'arch/um/kernel')
-rw-r--r-- | arch/um/kernel/kmsg_dump.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c index 6516ef1f8274..0224fcb36e22 100644 --- a/arch/um/kernel/kmsg_dump.c +++ b/arch/um/kernel/kmsg_dump.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include <linux/kmsg_dump.h> +#include <linux/spinlock.h> #include <linux/console.h> #include <linux/string.h> #include <shared/init.h> @@ -9,8 +10,11 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason) { + static struct kmsg_dump_iter iter; + static DEFINE_SPINLOCK(lock); static char line[1024]; struct console *con; + unsigned long flags; size_t len = 0; /* only dump kmsg when no console is available */ @@ -29,11 +33,18 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper, if (con) return; + if (!spin_trylock_irqsave(&lock, flags)) + return; + + kmsg_dump_rewind(&iter); + printf("kmsg_dump:\n"); - while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len)) { + while (kmsg_dump_get_line(&iter, true, line, sizeof(line), &len)) { line[len] = '\0'; printf("%s", line); } + + spin_unlock_irqrestore(&lock, flags); } static struct kmsg_dumper kmsg_dumper = { |