7412dc6d55
dump_stack() is called in panic(). If for some reason another CPU is holding the printk_cpu_sync and is unable to release it, the panic CPU will be unable to continue and print the stacktrace. Since non-panic CPUs are not allowed to store new printk messages anyway, there is no need to synchronize the stacktrace output in a panic situation. For the panic CPU, do not get the printk_cpu_sync because it is not needed and avoids a potential deadlock scenario in panic(). Link: https://lore.kernel.org/lkml/ZcIGKU8sxti38Kok@alley Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20240207134103.1357162-15-john.ogness@linutronix.de Signed-off-by: Petr Mladek <pmladek@suse.com>
126 lines
3.4 KiB
C
126 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Provide a default dump_stack() function for architectures
|
|
* which don't implement their own.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/buildid.h>
|
|
#include <linux/export.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sched/debug.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/atomic.h>
|
|
#include <linux/kexec.h>
|
|
#include <linux/utsname.h>
|
|
#include <linux/stop_machine.h>
|
|
|
|
static char dump_stack_arch_desc_str[128];
|
|
|
|
/**
|
|
* dump_stack_set_arch_desc - set arch-specific str to show with task dumps
|
|
* @fmt: printf-style format string
|
|
* @...: arguments for the format string
|
|
*
|
|
* The configured string will be printed right after utsname during task
|
|
* dumps. Usually used to add arch-specific system identifiers. If an
|
|
* arch wants to make use of such an ID string, it should initialize this
|
|
* as soon as possible during boot.
|
|
*/
|
|
void __init dump_stack_set_arch_desc(const char *fmt, ...)
|
|
{
|
|
va_list args;
|
|
|
|
va_start(args, fmt);
|
|
vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
|
|
fmt, args);
|
|
va_end(args);
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
|
|
#define BUILD_ID_FMT " %20phN"
|
|
#define BUILD_ID_VAL vmlinux_build_id
|
|
#else
|
|
#define BUILD_ID_FMT "%s"
|
|
#define BUILD_ID_VAL ""
|
|
#endif
|
|
|
|
/**
|
|
* dump_stack_print_info - print generic debug info for dump_stack()
|
|
* @log_lvl: log level
|
|
*
|
|
* Arch-specific dump_stack() implementations can use this function to
|
|
* print out the same debug information as the generic dump_stack().
|
|
*/
|
|
void dump_stack_print_info(const char *log_lvl)
|
|
{
|
|
printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FMT "\n",
|
|
log_lvl, raw_smp_processor_id(), current->pid, current->comm,
|
|
kexec_crash_loaded() ? "Kdump: loaded " : "",
|
|
print_tainted(),
|
|
init_utsname()->release,
|
|
(int)strcspn(init_utsname()->version, " "),
|
|
init_utsname()->version, BUILD_ID_VAL);
|
|
|
|
if (dump_stack_arch_desc_str[0] != '\0')
|
|
printk("%sHardware name: %s\n",
|
|
log_lvl, dump_stack_arch_desc_str);
|
|
|
|
print_worker_info(log_lvl, current);
|
|
print_stop_info(log_lvl, current);
|
|
}
|
|
|
|
/**
|
|
* show_regs_print_info - print generic debug info for show_regs()
|
|
* @log_lvl: log level
|
|
*
|
|
* show_regs() implementations can use this function to print out generic
|
|
* debug information.
|
|
*/
|
|
void show_regs_print_info(const char *log_lvl)
|
|
{
|
|
dump_stack_print_info(log_lvl);
|
|
}
|
|
|
|
static void __dump_stack(const char *log_lvl)
|
|
{
|
|
dump_stack_print_info(log_lvl);
|
|
show_stack(NULL, NULL, log_lvl);
|
|
}
|
|
|
|
/**
|
|
* dump_stack_lvl - dump the current task information and its stack trace
|
|
* @log_lvl: log level
|
|
*
|
|
* Architectures can override this implementation by implementing its own.
|
|
*/
|
|
asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
|
|
{
|
|
bool in_panic = this_cpu_in_panic();
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* Permit this cpu to perform nested stack dumps while serialising
|
|
* against other CPUs, unless this CPU is in panic.
|
|
*
|
|
* When in panic, non-panic CPUs are not permitted to store new
|
|
* printk messages so there is no need to synchronize the output.
|
|
* This avoids potential deadlock in panic() if another CPU is
|
|
* holding and unable to release the printk_cpu_sync.
|
|
*/
|
|
if (!in_panic)
|
|
printk_cpu_sync_get_irqsave(flags);
|
|
|
|
__dump_stack(log_lvl);
|
|
|
|
if (!in_panic)
|
|
printk_cpu_sync_put_irqrestore(flags);
|
|
}
|
|
EXPORT_SYMBOL(dump_stack_lvl);
|
|
|
|
asmlinkage __visible void dump_stack(void)
|
|
{
|
|
dump_stack_lvl(KERN_DEFAULT);
|
|
}
|
|
EXPORT_SYMBOL(dump_stack);
|