diff options
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/panic.c | 2 | ||||
-rw-r--r-- | kernel/printk/internal.h | 2 | ||||
-rw-r--r-- | kernel/printk/printk.c | 8 | ||||
-rw-r--r-- | kernel/printk/printk_safe.c | 32 | ||||
-rw-r--r-- | kernel/reboot.c | 2 |
5 files changed, 45 insertions, 1 deletions
diff --git a/kernel/panic.c b/kernel/panic.c index a3c758dba15a..4cf13c37bd08 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -297,6 +297,7 @@ void panic(const char *fmt, ...) * unfortunately means it may not be hardened to work in a * panic situation. */ + try_block_console_kthreads(10000); smp_send_stop(); } else { /* @@ -304,6 +305,7 @@ void panic(const char *fmt, ...) * kmsg_dump, we will need architecture dependent extra * works in addition to stopping other CPUs. */ + try_block_console_kthreads(10000); crash_smp_send_stop(); } diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index d947ca6c84f9..e7d8578860ad 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -20,6 +20,8 @@ enum printk_info_flags { LOG_CONT = 8, /* text is a fragment of a continuation line */ }; +extern bool block_console_kthreads; + __printf(4, 0) int vprintk_store(int facility, int level, const struct dev_printk_info *dev_info, diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index ea3dd55709e7..b095fb5f5f61 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -250,6 +250,9 @@ static atomic_t console_kthreads_active = ATOMIC_INIT(0); #define console_kthread_printing_exit() \ atomic_dec(&console_kthreads_active) +/* Block console kthreads to avoid processing new messages. */ +bool block_console_kthreads; + /* * Helper macros to handle lockdep when locking/unlocking console_sem. We use * macros instead of functions so that _RET_IP_ contains useful information. @@ -3729,7 +3732,10 @@ static bool printer_should_wake(struct console *con, u64 seq) return true; if (con->blocked || - console_kthreads_atomically_blocked()) { + console_kthreads_atomically_blocked() || + block_console_kthreads || + system_state > SYSTEM_RUNNING || + oops_in_progress) { return false; } diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index ef0f9a2044da..caac4de1ea59 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -8,7 +8,9 @@ #include <linux/smp.h> #include <linux/cpumask.h> #include <linux/printk.h> +#include <linux/console.h> #include <linux/kprobes.h> +#include <linux/delay.h> #include "internal.h" @@ -50,3 +52,33 @@ asmlinkage int vprintk(const char *fmt, va_list args) return vprintk_default(fmt, args); } EXPORT_SYMBOL(vprintk); + +/** + * try_block_console_kthreads() - Try to block console kthreads and + * make the global console_lock() avaialble + * + * @timeout_ms: The maximum time (in ms) to wait. + * + * Prevent console kthreads from starting processing new messages. Wait + * until the global console_lock() become available. + * + * Context: Can be called in any context. + */ +void try_block_console_kthreads(int timeout_ms) +{ + block_console_kthreads = true; + + /* Do not wait when the console lock could not be safely taken. */ + if (this_cpu_read(printk_context) || in_nmi()) + return; + + while (timeout_ms > 0) { + if (console_trylock()) { + console_unlock(); + return; + } + + udelay(1000); + timeout_ms -= 1; + } +} diff --git a/kernel/reboot.c b/kernel/reboot.c index b5a71d1ff603..80564ffafabf 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -82,6 +82,7 @@ void kernel_restart_prepare(char *cmd) { blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); system_state = SYSTEM_RESTART; + try_block_console_kthreads(10000); usermodehelper_disable(); device_shutdown(); } @@ -270,6 +271,7 @@ static void kernel_shutdown_prepare(enum system_states state) blocking_notifier_call_chain(&reboot_notifier_list, (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL); system_state = state; + try_block_console_kthreads(10000); usermodehelper_disable(); device_shutdown(); } |