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ebf0a36a32
Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user). Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred. Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers. Add log level argument to dump_mem() as a preparation to introduce show_stack_loglvl(). [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Rich Felker <dalias@libc.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200418201944.482088-30-dima@arista.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
206 lines
4.2 KiB
C
206 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/bug.h>
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#include <linux/io.h>
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#include <linux/types.h>
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#include <linux/kdebug.h>
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/sched/debug.h>
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#include <linux/sched/task_stack.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/kernel.h>
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#include <linux/kexec.h>
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#include <linux/sched/signal.h>
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#include <linux/extable.h>
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#include <linux/module.h> /* print_modules */
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#include <asm/unwinder.h>
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#include <asm/traps.h>
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static DEFINE_SPINLOCK(die_lock);
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void die(const char *str, struct pt_regs *regs, long err)
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{
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static int die_counter;
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oops_enter();
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spin_lock_irq(&die_lock);
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console_verbose();
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bust_spinlocks(1);
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printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
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print_modules();
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show_regs(regs);
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printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
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task_pid_nr(current), task_stack_page(current) + 1);
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if (!user_mode(regs) || in_interrupt())
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dump_mem("Stack: ", KERN_DEFAULT, regs->regs[15],
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THREAD_SIZE + (unsigned long)task_stack_page(current));
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notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
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bust_spinlocks(0);
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add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
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spin_unlock_irq(&die_lock);
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oops_exit();
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if (kexec_should_crash(current))
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crash_kexec(regs);
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if (in_interrupt())
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panic("Fatal exception in interrupt");
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if (panic_on_oops)
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panic("Fatal exception");
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do_exit(SIGSEGV);
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}
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void die_if_kernel(const char *str, struct pt_regs *regs, long err)
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{
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if (!user_mode(regs))
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die(str, regs, err);
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}
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/*
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* try and fix up kernelspace address errors
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* - userspace errors just cause EFAULT to be returned, resulting in SEGV
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* - kernel/userspace interfaces cause a jump to an appropriate handler
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* - other kernel errors are bad
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*/
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void die_if_no_fixup(const char *str, struct pt_regs *regs, long err)
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{
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if (!user_mode(regs)) {
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const struct exception_table_entry *fixup;
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fixup = search_exception_tables(regs->pc);
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if (fixup) {
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regs->pc = fixup->fixup;
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return;
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}
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die(str, regs, err);
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}
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}
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#ifdef CONFIG_GENERIC_BUG
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static void handle_BUG(struct pt_regs *regs)
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{
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const struct bug_entry *bug;
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unsigned long bugaddr = regs->pc;
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enum bug_trap_type tt;
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if (!is_valid_bugaddr(bugaddr))
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goto invalid;
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bug = find_bug(bugaddr);
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/* Switch unwinders when unwind_stack() is called */
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if (bug->flags & BUGFLAG_UNWINDER)
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unwinder_faulted = 1;
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tt = report_bug(bugaddr, regs);
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if (tt == BUG_TRAP_TYPE_WARN) {
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regs->pc += instruction_size(bugaddr);
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return;
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}
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invalid:
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die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
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}
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int is_valid_bugaddr(unsigned long addr)
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{
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insn_size_t opcode;
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if (addr < PAGE_OFFSET)
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return 0;
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if (probe_kernel_address((insn_size_t *)addr, opcode))
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return 0;
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if (opcode == TRAPA_BUG_OPCODE)
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return 1;
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return 0;
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}
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#endif
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/*
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* Generic trap handler.
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*/
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BUILD_TRAP_HANDLER(debug)
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{
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TRAP_HANDLER_DECL;
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/* Rewind */
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regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
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if (notify_die(DIE_TRAP, "debug trap", regs, 0, vec & 0xff,
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SIGTRAP) == NOTIFY_STOP)
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return;
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force_sig(SIGTRAP);
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}
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/*
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* Special handler for BUG() traps.
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*/
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BUILD_TRAP_HANDLER(bug)
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{
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TRAP_HANDLER_DECL;
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/* Rewind */
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regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
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if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
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SIGTRAP) == NOTIFY_STOP)
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return;
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#ifdef CONFIG_GENERIC_BUG
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if (__kernel_text_address(instruction_pointer(regs))) {
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insn_size_t insn = *(insn_size_t *)instruction_pointer(regs);
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if (insn == TRAPA_BUG_OPCODE)
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handle_BUG(regs);
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return;
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}
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#endif
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force_sig(SIGTRAP);
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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extern void arch_ftrace_nmi_enter(void);
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extern void arch_ftrace_nmi_exit(void);
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#else
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static inline void arch_ftrace_nmi_enter(void) { }
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static inline void arch_ftrace_nmi_exit(void) { }
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#endif
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BUILD_TRAP_HANDLER(nmi)
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{
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unsigned int cpu = smp_processor_id();
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TRAP_HANDLER_DECL;
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arch_ftrace_nmi_enter();
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nmi_enter();
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nmi_count(cpu)++;
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switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) {
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case NOTIFY_OK:
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case NOTIFY_STOP:
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break;
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case NOTIFY_BAD:
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die("Fatal Non-Maskable Interrupt", regs, SIGINT);
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default:
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printk(KERN_ALERT "Got NMI, but nobody cared. Ignoring...\n");
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break;
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}
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nmi_exit();
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arch_ftrace_nmi_exit();
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}
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