taint: add explicit flag to show whether lock dep is still OK.

Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

arch/alpha/kernel/traps.c

@@ -186,7 +186,7 @@ die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
 #endif
 	printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err);
 	dik_show_regs(regs, r9_15);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	dik_show_trace((unsigned long *)(regs+1));
 	dik_show_code((unsigned int *)regs->pc);
 

arch/arm/kernel/traps.c

@@ -296,7 +296,7 @@ static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 
 	bust_spinlocks(0);
 	die_owner = -1;
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	die_nest_count--;
 	if (!die_nest_count)
 		/* Nest count reaches zero, release the lock. */

arch/arm64/kernel/traps.c

@@ -242,7 +242,7 @@ void die(const char *str, struct pt_regs *regs, int err)
 		crash_kexec(regs);
 
 	bust_spinlocks(0);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	raw_spin_unlock_irq(&die_lock);
 	oops_exit();
 

arch/avr32/kernel/traps.c

@@ -61,7 +61,7 @@ void die(const char *str, struct pt_regs *regs, long err)
 	show_regs_log_lvl(regs, KERN_EMERG);
 	show_stack_log_lvl(current, regs->sp, regs, KERN_EMERG);
 	bust_spinlocks(0);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irq(&die_lock);
 
 	if (in_interrupt())

arch/hexagon/kernel/traps.c

@@ -225,7 +225,7 @@ int die(const char *str, struct pt_regs *regs, long err)
 	do_show_stack(current, &regs->r30, pt_elr(regs));
 
 	bust_spinlocks(0);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 
 	spin_unlock_irq(&die.lock);
 

arch/ia64/kernel/traps.c

@@ -72,7 +72,7 @@ die (const char *str, struct pt_regs *regs, long err)
 
 	bust_spinlocks(0);
 	die.lock_owner = -1;
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irq(&die.lock);
 
 	if (!regs)

arch/m68k/kernel/traps.c

@@ -1176,7 +1176,7 @@ void die_if_kernel (char *str, struct pt_regs *fp, int nr)
 	console_verbose();
 	printk("%s: %08x\n",str,nr);
 	show_registers(fp);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	do_exit(SIGSEGV);
 }
 

arch/mips/kernel/traps.c

@@ -396,7 +396,7 @@ void __noreturn die(const char *str, struct pt_regs *regs)
 
 	printk("%s[#%d]:\n", str, ++die_counter);
 	show_registers(regs);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	raw_spin_unlock_irq(&die_lock);
 
 	oops_exit();

arch/parisc/kernel/traps.c

@@ -282,7 +282,7 @@ void die_if_kernel(char *str, struct pt_regs *regs, long err)
 
 	show_regs(regs);
 	dump_stack();
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 
 	if (in_interrupt())
 		panic("Fatal exception in interrupt");

arch/powerpc/kernel/traps.c

@@ -138,7 +138,7 @@ static void __kprobes oops_end(unsigned long flags, struct pt_regs *regs,
 {
 	bust_spinlocks(0);
 	die_owner = -1;
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	die_nest_count--;
 	oops_exit();
 	printk("\n");

arch/s390/kernel/traps.c

@@ -271,7 +271,7 @@ void die(struct pt_regs *regs, const char *str)
 	print_modules();
 	show_regs(regs);
 	bust_spinlocks(0);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irq(&die_lock);
 	if (in_interrupt())
 		panic("Fatal exception in interrupt");

arch/sh/kernel/traps.c

@@ -38,7 +38,7 @@ void die(const char *str, struct pt_regs *regs, long err)
 	notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
 
 	bust_spinlocks(0);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irq(&die_lock);
 	oops_exit();
 

arch/sparc/kernel/setup_64.c

@@ -115,7 +115,7 @@ static void __init process_switch(char c)
 			break;
 		}
 		cheetah_pcache_forced_on = 1;
-		add_taint(TAINT_MACHINE_CHECK);
+		add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 		cheetah_enable_pcache();
 		break;
 

arch/sparc/kernel/traps_32.c

@@ -58,7 +58,7 @@ void die_if_kernel(char *str, struct pt_regs *regs)
 
 	printk("%s(%d): %s [#%d]\n", current->comm, task_pid_nr(current), str, ++die_counter);
 	show_regs(regs);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 
 	__SAVE; __SAVE; __SAVE; __SAVE;
 	__SAVE; __SAVE; __SAVE; __SAVE;

arch/sparc/kernel/traps_64.c

@@ -2383,7 +2383,7 @@ void die_if_kernel(char *str, struct pt_regs *regs)
 	notify_die(DIE_OOPS, str, regs, 0, 255, SIGSEGV);
 	__asm__ __volatile__("flushw");
 	show_regs(regs);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	if (regs->tstate & TSTATE_PRIV) {
 		struct thread_info *tp = current_thread_info();
 		struct reg_window *rw = (struct reg_window *)

arch/unicore32/kernel/traps.c

@@ -231,7 +231,7 @@ void die(const char *str, struct pt_regs *regs, int err)
 	ret = __die(str, err, thread, regs);
 
 	bust_spinlocks(0);
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irq(&die_lock);
 	oops_exit();
 

arch/x86/kernel/cpu/amd.c

@@ -220,8 +220,7 @@ static void __cpuinit amd_k7_smp_check(struct cpuinfo_x86 *c)
 	 */
 	WARN_ONCE(1, "WARNING: This combination of AMD"
 		" processors is not suitable for SMP.\n");
-	if (!test_taint(TAINT_UNSAFE_SMP))
-		add_taint(TAINT_UNSAFE_SMP);
+	add_taint(TAINT_UNSAFE_SMP, LOCKDEP_NOW_UNRELIABLE);
 
 valid_k7:
 	;

arch/x86/kernel/cpu/mcheck/mce.c

@@ -1085,7 +1085,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 		/*
 		 * Set taint even when machine check was not enabled.
 		 */
-		add_taint(TAINT_MACHINE_CHECK);
+		add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 
 		severity = mce_severity(&m, cfg->tolerant, NULL);
 

arch/x86/kernel/cpu/mcheck/p5.c

@@ -33,7 +33,7 @@ static void pentium_machine_check(struct pt_regs *regs, long error_code)
 			smp_processor_id());
 	}
 
-	add_taint(TAINT_MACHINE_CHECK);
+	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 }
 
 /* Set up machine check reporting for processors with Intel style MCE: */

arch/x86/kernel/cpu/mcheck/winchip.c

@@ -15,7 +15,7 @@
 static void winchip_machine_check(struct pt_regs *regs, long error_code)
 {
 	printk(KERN_EMERG "CPU0: Machine Check Exception.\n");
-	add_taint(TAINT_MACHINE_CHECK);
+	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 }
 
 /* Set up machine check reporting on the Winchip C6 series */

arch/x86/kernel/cpu/mtrr/generic.c

@@ -542,7 +542,7 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base,
 
 		if (tmp != mask_lo) {
 			printk(KERN_WARNING "mtrr: your BIOS has configured an incorrect mask, fixing it.\n");
-			add_taint(TAINT_FIRMWARE_WORKAROUND);
+			add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
 			mask_lo = tmp;
 		}
 	}

arch/x86/kernel/dumpstack.c

@@ -232,7 +232,7 @@ void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 
 	bust_spinlocks(0);
 	die_owner = -1;
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	die_nest_count--;
 	if (!die_nest_count)
 		/* Nest count reaches zero, release the lock. */

arch/xtensa/kernel/traps.c

@@ -524,7 +524,7 @@ void die(const char * str, struct pt_regs * regs, long err)
 	if (!user_mode(regs))
 		show_stack(NULL, (unsigned long*)regs->areg[1]);
 
-	add_taint(TAINT_DIE);
+	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irq(&die_lock);
 
 	if (in_interrupt())

drivers/acpi/custom_method.c

@@ -66,7 +66,7 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf,
 		buf = NULL;
 		if (ACPI_FAILURE(status))
 			return -EINVAL;
-		add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
+		add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
 	}
 
 	return count;

drivers/acpi/osl.c

@@ -661,7 +661,7 @@ static void acpi_table_taint(struct acpi_table_header *table)
 	pr_warn(PREFIX
 		"Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n",
 		table->signature, table->oem_table_id);
-	add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
+	add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
 }
 
 

drivers/base/regmap/regmap-debugfs.c

@@ -267,7 +267,7 @@ static ssize_t regmap_map_write_file(struct file *file,
 		return -EINVAL;
 
 	/* Userspace has been fiddling around behind the kernel's back */
-	add_taint(TAINT_USER);
+	add_taint(TAINT_USER, LOCKDEP_NOW_UNRELIABLE);
 
 	regmap_write(map, reg, value);
 	return buf_size;

include/linux/kernel.h

@@ -398,7 +398,11 @@ extern int panic_on_unrecovered_nmi;
 extern int panic_on_io_nmi;
 extern int sysctl_panic_on_stackoverflow;
 extern const char *print_tainted(void);
-extern void add_taint(unsigned flag);
+enum lockdep_ok {
+	LOCKDEP_STILL_OK,
+	LOCKDEP_NOW_UNRELIABLE
+};
+extern void add_taint(unsigned flag, enum lockdep_ok);
 extern int test_taint(unsigned flag);
 extern unsigned long get_taint(void);
 extern int root_mountflags;

kernel/module.c

@@ -197,9 +197,10 @@ static inline int strong_try_module_get(struct module *mod)
 		return -ENOENT;
 }
 
-static inline void add_taint_module(struct module *mod, unsigned flag)
+static inline void add_taint_module(struct module *mod, unsigned flag,
+				    enum lockdep_ok lockdep_ok)
 {
-	add_taint(flag);
+	add_taint(flag, lockdep_ok);
 	mod->taints |= (1U << flag);
 }
 
@@ -727,7 +728,7 @@ static inline int try_force_unload(unsigned int flags)
 {
 	int ret = (flags & O_TRUNC);
 	if (ret)
-		add_taint(TAINT_FORCED_RMMOD);
+		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
 	return ret;
 }
 #else
@@ -1138,7 +1139,7 @@ static int try_to_force_load(struct module *mod, const char *reason)
 	if (!test_taint(TAINT_FORCED_MODULE))
 		printk(KERN_WARNING "%s: %s: kernel tainted.\n",
 		       mod->name, reason);
-	add_taint_module(mod, TAINT_FORCED_MODULE);
+	add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
 	return 0;
 #else
 	return -ENOEXEC;
@@ -2147,7 +2148,8 @@ static void set_license(struct module *mod, const char *license)
 		if (!test_taint(TAINT_PROPRIETARY_MODULE))
 			printk(KERN_WARNING "%s: module license '%s' taints "
 				"kernel.\n", mod->name, license);
-		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
 	}
 }
 
@@ -2700,10 +2702,10 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
 	}
 
 	if (!get_modinfo(info, "intree"))
-		add_taint_module(mod, TAINT_OOT_MODULE);
+		add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
 
 	if (get_modinfo(info, "staging")) {
-		add_taint_module(mod, TAINT_CRAP);
+		add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
 		printk(KERN_WARNING "%s: module is from the staging directory,"
 		       " the quality is unknown, you have been warned.\n",
 		       mod->name);
@@ -2869,15 +2871,17 @@ static int check_module_license_and_versions(struct module *mod)
 	 * using GPL-only symbols it needs.
 	 */
 	if (strcmp(mod->name, "ndiswrapper") == 0)
-		add_taint(TAINT_PROPRIETARY_MODULE);
+		add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
 
 	/* driverloader was caught wrongly pretending to be under GPL */
 	if (strcmp(mod->name, "driverloader") == 0)
-		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
 
 	/* lve claims to be GPL but upstream won't provide source */
 	if (strcmp(mod->name, "lve") == 0)
-		add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
 
 #ifdef CONFIG_MODVERSIONS
 	if ((mod->num_syms && !mod->crcs)
@@ -3197,7 +3201,7 @@ again:
 			    "%s: module verification failed: signature and/or"
 			    " required key missing - tainting kernel\n",
 			    mod->name);
-		add_taint_module(mod, TAINT_FORCED_MODULE);
+		add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_STILL_OK);
 	}
 #endif
 

kernel/panic.c

@@ -259,26 +259,19 @@ unsigned long get_taint(void)
 	return tainted_mask;
 }
 
-void add_taint(unsigned flag)
+/**
+ * add_taint: add a taint flag if not already set.
+ * @flag: one of the TAINT_* constants.
+ * @lockdep_ok: whether lock debugging is still OK.
+ *
+ * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
+ * some notewortht-but-not-corrupting cases, it can be set to true.
+ */
+void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
 {
-	/*
-	 * Can't trust the integrity of the kernel anymore.
-	 * We don't call directly debug_locks_off() because the issue
-	 * is not necessarily serious enough to set oops_in_progress to 1
-	 * Also we want to keep up lockdep for staging/out-of-tree
-	 * development and post-warning case.
-	 */
-	switch (flag) {
-	case TAINT_CRAP:
-	case TAINT_OOT_MODULE:
-	case TAINT_WARN:
-	case TAINT_FIRMWARE_WORKAROUND:
-		break;
-
-	default:
-		if (__debug_locks_off())
-			printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
-	}
+	if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
+		printk(KERN_WARNING
+		       "Disabling lock debugging due to kernel taint\n");
 
 	set_bit(flag, &tainted_mask);
 }
@@ -421,7 +414,8 @@ static void warn_slowpath_common(const char *file, int line, void *caller,
 	print_modules();
 	dump_stack();
 	print_oops_end_marker();
-	add_taint(taint);
+	/* Just a warning, don't kill lockdep. */
+	add_taint(taint, LOCKDEP_STILL_OK);
 }
 
 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)

kernel/sched/core.c

@@ -2785,7 +2785,7 @@ static noinline void __schedule_bug(struct task_struct *prev)
 	if (irqs_disabled())
 		print_irqtrace_events(prev);
 	dump_stack();
-	add_taint(TAINT_WARN);
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
 }
 
 /*

kernel/sysctl.c

@@ -2006,7 +2006,7 @@ static int proc_taint(struct ctl_table *table, int write,
 		int i;
 		for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
 			if ((tmptaint >> i) & 1)
-				add_taint(i);
+				add_taint(i, LOCKDEP_STILL_OK);
 		}
 	}
 

lib/bug.c

@@ -166,7 +166,8 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 		print_modules();
 		show_regs(regs);
 		print_oops_end_marker();
-		add_taint(BUG_GET_TAINT(bug));
+		/* Just a warning, don't kill lockdep. */
+		add_taint(BUG_GET_TAINT(bug), LOCKDEP_STILL_OK);
 		return BUG_TRAP_TYPE_WARN;
 	}
 

mm/memory.c

@@ -716,7 +716,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
 		print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
 				(unsigned long)vma->vm_file->f_op->mmap);
 	dump_stack();
-	add_taint(TAINT_BAD_PAGE);
+	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 
 static inline bool is_cow_mapping(vm_flags_t flags)

mm/page_alloc.c

@@ -320,7 +320,7 @@ static void bad_page(struct page *page)
 out:
 	/* Leave bad fields for debug, except PageBuddy could make trouble */
 	reset_page_mapcount(page); /* remove PageBuddy */
-	add_taint(TAINT_BAD_PAGE);
+	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 
 /*

mm/slab.c

@@ -812,7 +812,7 @@ static void __slab_error(const char *function, struct kmem_cache *cachep,
 	printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
 	       function, cachep->name, msg);
 	dump_stack();
-	add_taint(TAINT_BAD_PAGE);
+	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 #endif
 

mm/slub.c

@@ -562,7 +562,7 @@ static void slab_bug(struct kmem_cache *s, char *fmt, ...)
 	printk(KERN_ERR "----------------------------------------"
 			"-------------------------------------\n\n");
 
-	add_taint(TAINT_BAD_PAGE);
+	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 
 static void slab_fix(struct kmem_cache *s, char *fmt, ...)

sound/soc/soc-core.c

@@ -251,7 +251,7 @@ static ssize_t codec_reg_write_file(struct file *file,
 		return -EINVAL;
 
 	/* Userspace has been fiddling around behind the kernel's back */
-	add_taint(TAINT_USER);
+	add_taint(TAINT_USER, LOCKDEP_NOW_UNRELIABLE);
 
 	snd_soc_write(codec, reg, value);
 	return buf_size;