[PATCH] MODSIGN: Don't taint unless signature enforcing is enabled

[PATCH] MODSIGN: Don't taint unless signature enforcing is enabled

[Josh Boyer]

With module signing enabled but not in enforcing mode, we don't consider
unsigned modules to be an error.  However, we only mark sig_ok as true if
a signature verified.  This causes the module to be tainted with the
TAINT_FORCED_MODULE flag.  That in turn taints the kernel, which also
disables lockdep.

Tainting the module and kernel when we don't consider something to be an
error seems excessive.  This marks sig_ok as true if we aren't in enforcing
mode.

Reported-by: Frank Ch. Eigler <fche@redhat.com>
Signed-off-by: Josh Boyer <jwboyer@redhat.com>
---
 kernel/module.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/module.c b/kernel/module.c
index 250092c..a50172e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2443,8 +2443,10 @@ static int module_sig_check(struct load_info *info)
 	if (err < 0 && fips_enabled)
 		panic("Module verification failed with error %d in FIPS mode\n",
 		      err);
-	if (err == -ENOKEY && !sig_enforce)
+	if (err == -ENOKEY && !sig_enforce) {
+		info->sig_ok = true;
 		err = 0;
+	}
 
 	return err;
 }
-- 
1.8.0.1

Re: [PATCH] MODSIGN: Don't taint unless signature enforcing is enabled

[Rusty Russell]

Josh Boyer <jwboyer@redhat.com> writes:
> With module signing enabled but not in enforcing mode, we don't consider
> unsigned modules to be an error.  However, we only mark sig_ok as true if
> a signature verified.  This causes the module to be tainted with the
> TAINT_FORCED_MODULE flag.

Wait, what?  So, what does CONFIG_MODULE_SIG=y with MODULE_SIG_FORCE=n
mean?  Why not just call that CONFIG_USELESS_BLOAT? :)

>  That in turn taints the kernel, which also disables lockdep.

Yeah, lockdep is oversensitive.  This has been argued before, take it up
with Ingo.  Perhaps we need a taint flag bit to indicate that lockdep
should actually be disabled?

> Tainting the module and kernel when we don't consider something to be an
> error seems excessive.  This marks sig_ok as true if we aren't in enforcing
> mode.

If we were to do this, please follow Plauger's Law: "Don't patch bad
code - rewrite it."

In this case, rip out the now-useless sig_ok field.

Thanks,
Rusty.

> diff --git a/kernel/module.c b/kernel/module.c
> index 250092c..a50172e 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -2443,8 +2443,10 @@ static int module_sig_check(struct load_info *info)
>  	if (err < 0 && fips_enabled)
>  		panic("Module verification failed with error %d in FIPS mode\n",
>  		      err);
> -	if (err == -ENOKEY && !sig_enforce)
> +	if (err == -ENOKEY && !sig_enforce) {
> +		info->sig_ok = true;
>  		err = 0;
> +	}
>  
>  	return err;
>  }
> -- 
> 1.8.0.1

Re: [PATCH] MODSIGN: Don't taint unless signature enforcing is enabled

[Josh Boyer]

On Mon, Jan 07, 2013 at 11:39:47AM +1030, Rusty Russell wrote:
> Josh Boyer <jwboyer@redhat.com> writes:
> > With module signing enabled but not in enforcing mode, we don't consider
> > unsigned modules to be an error.  However, we only mark sig_ok as true if
> > a signature verified.  This causes the module to be tainted with the
> > TAINT_FORCED_MODULE flag.
> 
> Wait, what?  So, what does CONFIG_MODULE_SIG=y with MODULE_SIG_FORCE=n
> mean?  Why not just call that CONFIG_USELESS_BLOAT? :)

You can still enable enforcing mode with that configuration by passing
sig_enforce=1 as a kernel parameter.  Some distros default to this
configuration.

> >  That in turn taints the kernel, which also disables lockdep.
> 
> Yeah, lockdep is oversensitive.  This has been argued before, take it up
> with Ingo.  Perhaps we need a taint flag bit to indicate that lockdep
> should actually be disabled?

Well, sure maybe.  Frank already pointed out that the OOT taint doesn't
disable lockdep.  Having something more general would be good.  If there
isn't an easy way to do that, adding a TAINT_UNSIGNED to be used instead
of TAINT_FORCED_MODULE might work.  I've CC'd Ingo and Peter.

> > Tainting the module and kernel when we don't consider something to be an
> > error seems excessive.  This marks sig_ok as true if we aren't in enforcing
> > mode.
> 
> If we were to do this, please follow Plauger's Law: "Don't patch bad
> code - rewrite it."
> 
> In this case, rip out the now-useless sig_ok field.

OK.  I'll respin with that change if nothing else seems workable.

josh

[PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Josh Boyer]

With module signing enabled but not in enforcing mode, we don't consider
unsigned modules to be an error.  However, if we encounter an unsigned
module we currently taint the module and kernel with TAINT_FORCED_MODULE.
That also disables lockdep within the kernel.

Given that we aren't in enforcing mode in this case, and we aren't
actually forcing the module to be loaded, that seems to be an incorrect
representation of what happened on module load.  This adds a new
TAINT_NOKEY_MODULE flag to be used in this case instead.  We also allow
lockdep to continue to work in this case, similar to the TAINT_OOT_MODULE
and TAINT_WARN cases.

Reported-by: Frank Ch. Eigler <fche@redhat.com>
Signed-off-by: Josh Boyer <jwboyer@redhat.com>
---
 include/linux/kernel.h | 1 +
 kernel/module.c        | 4 +++-
 kernel/panic.c         | 3 +++
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index c566927..a2bbddb 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -427,6 +427,7 @@ extern enum system_states {
 #define TAINT_CRAP			10
 #define TAINT_FIRMWARE_WORKAROUND	11
 #define TAINT_OOT_MODULE		12
+#define TAINT_NOKEY_MODULE		13
 
 extern const char hex_asc[];
 #define hex_asc_lo(x)	hex_asc[((x) & 0x0f)]
diff --git a/kernel/module.c b/kernel/module.c
index 250092c..5dc9263 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1025,6 +1025,8 @@ static size_t module_flags_taint(struct module *mod, char *buf)
 		buf[l++] = 'F';
 	if (mod->taints & (1 << TAINT_CRAP))
 		buf[l++] = 'C';
+	if (mod->taints & (1 << TAINT_NOKEY_MODULE))
+		buf[l++] = 'K';
 	/*
 	 * TAINT_FORCED_RMMOD: could be added.
 	 * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
@@ -3116,7 +3118,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 #ifdef CONFIG_MODULE_SIG
 	mod->sig_ok = info->sig_ok;
 	if (!mod->sig_ok)
-		add_taint_module(mod, TAINT_FORCED_MODULE);
+		add_taint_module(mod, TAINT_NOKEY_MODULE);
 #endif
 
 	/* Now module is in final location, initialize linked lists, etc. */
diff --git a/kernel/panic.c b/kernel/panic.c
index e1b2822..e909abb 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -206,6 +206,7 @@ static const struct tnt tnts[] = {
 	{ TAINT_CRAP,			'C', ' ' },
 	{ TAINT_FIRMWARE_WORKAROUND,	'I', ' ' },
 	{ TAINT_OOT_MODULE,		'O', ' ' },
+	{ TAINT_NOKEY_MODULE,		'K', ' ' },
 };
 
 /**
@@ -224,6 +225,7 @@ static const struct tnt tnts[] = {
  *  'C' - modules from drivers/staging are loaded.
  *  'I' - Working around severe firmware bug.
  *  'O' - Out-of-tree module has been loaded.
+ *  'K' - Module with missing or unknown signature key has been loaded.
  *
  *	The string is overwritten by the next call to print_tainted().
  */
@@ -273,6 +275,7 @@ void add_taint(unsigned flag)
 	case TAINT_OOT_MODULE:
 	case TAINT_WARN:
 	case TAINT_FIRMWARE_WORKAROUND:
+	case TAINT_NOKEY_MODULE:
 		break;
 
 	default:
-- 
1.8.0.2

Re: [PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Rusty Russell]

Josh Boyer <jwboyer@redhat.com> writes:
> With module signing enabled but not in enforcing mode, we don't consider
> unsigned modules to be an error.  However, if we encounter an unsigned
> module we currently taint the module and kernel with TAINT_FORCED_MODULE.
> That also disables lockdep within the kernel.

How about this, instead?  Ingo?

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>

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 272666d..2fca8ca 100644
--- a/arch/alpha/kernel/traps.c
+++ b/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, false);
 	dik_show_trace((unsigned long *)(regs+1));
 	dik_show_code((unsigned int *)regs->pc);
 
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index b0179b8..02d2e1a 100644
--- a/arch/arm/kernel/traps.c
+++ b/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, false);
 	die_nest_count--;
 	if (!die_nest_count)
 		/* Nest count reaches zero, release the lock. */
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 3883f84..d4fe267 100644
--- a/arch/arm64/kernel/traps.c
+++ b/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, false);
 	raw_spin_unlock_irq(&die_lock);
 	oops_exit();
 
diff --git a/arch/avr32/kernel/traps.c b/arch/avr32/kernel/traps.c
index 3d760c0..4c084d9 100644
--- a/arch/avr32/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 
 	if (in_interrupt())
diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
index a41eeb8..0637a86 100644
--- a/arch/hexagon/kernel/traps.c
+++ b/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, false);
 
 	spin_unlock_irq(&die.lock);
 
diff --git a/arch/ia64/kernel/traps.c b/arch/ia64/kernel/traps.c
index bd42b76..e4e71c5 100644
--- a/arch/ia64/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die.lock);
 
 	if (!regs)
diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index cbc624a..18798af 100644
--- a/arch/m68k/kernel/traps.c
+++ b/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, false);
 	do_exit(SIGSEGV);
 }
 
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index cf7ac54..a88f820 100644
--- a/arch/mips/kernel/traps.c
+++ b/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, false);
 	raw_spin_unlock_irq(&die_lock);
 
 	oops_exit();
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 45ba99f..614dc31 100644
--- a/arch/parisc/kernel/traps.c
+++ b/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, false);
 
 	if (in_interrupt())
 		panic("Fatal exception in interrupt");
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 3251840..ec875b8 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/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, false);
 	die_nest_count--;
 	oops_exit();
 	printk("\n");
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index 70ecfc5..09ff735 100644
--- a/arch/s390/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 	if (in_interrupt())
 		panic("Fatal exception in interrupt");
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index 72246bc..ae0759d 100644
--- a/arch/sh/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 	oops_exit();
 
diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c
index 0eaf005..269a0d5 100644
--- a/arch/sparc/kernel/setup_64.c
+++ b/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, false);
 		cheetah_enable_pcache();
 		break;
 
diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index a5785ea..13f09de 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/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, false);
 
 	__SAVE; __SAVE; __SAVE; __SAVE;
 	__SAVE; __SAVE; __SAVE; __SAVE;
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index e7ecf15..5db8b53 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/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, false);
 	if (regs->tstate & TSTATE_PRIV) {
 		struct thread_info *tp = current_thread_info();
 		struct reg_window *rw = (struct reg_window *)
diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c
index 2054f0d..2a2351b 100644
--- a/arch/unicore32/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 	oops_exit();
 
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 15239ff..b9d242f 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/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, false);
 
 valid_k7:
 	;
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 80dbda8..bc43a1f 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/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, false);
 
 		severity = mce_severity(&m, cfg->tolerant, NULL);
 
diff --git a/arch/x86/kernel/cpu/mcheck/p5.c b/arch/x86/kernel/cpu/mcheck/p5.c
index 2d5454c..544cdee 100644
--- a/arch/x86/kernel/cpu/mcheck/p5.c
+++ b/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, false);
 }
 
 /* Set up machine check reporting for processors with Intel style MCE: */
diff --git a/arch/x86/kernel/cpu/mcheck/winchip.c b/arch/x86/kernel/cpu/mcheck/winchip.c
index 2d7998f..6cb85e03a 100644
--- a/arch/x86/kernel/cpu/mcheck/winchip.c
+++ b/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, false);
 }
 
 /* Set up machine check reporting on the Winchip C6 series */
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index e9fe907..c00a664 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/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, true);
 			mask_lo = tmp;
 		}
 	}
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index ae42418b..7ad7830 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/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, false);
 	die_nest_count--;
 	if (!die_nest_count)
 		/* Nest count reaches zero, release the lock. */
diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index 01e0111..fc1bef8 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 
 	if (in_interrupt())
diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c
index 5d42c24..000c701 100644
--- a/drivers/acpi/custom_method.c
+++ b/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, false);
 	}
 
 	return count;
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 3ff2678..15b803e 100644
--- a/drivers/acpi/osl.c
+++ b/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, false);
 }
 
 
diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 07aad78..32a5be2 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -232,7 +232,7 @@ 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, false);
 
 	regmap_write(map, reg, value);
 	return buf_size;
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 86e2f4a..7acca64 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -230,7 +230,7 @@ dmar_parse_one_rhsa(struct acpi_dmar_header *header)
 		}
 	}
 	WARN_TAINT(
-		1, TAINT_FIRMWARE_WORKAROUND,
+		1, TAINT_FIRMWARE_WORKAROUND, true,
 		"Your BIOS is broken; RHSA refers to non-existent DMAR unit at %llx\n"
 		"BIOS vendor: %s; Ver: %s; Product Version: %s\n",
 		drhd->reg_base_addr,
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index c566927..53c14cb 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -398,7 +398,7 @@ 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);
+extern void add_taint(unsigned flag, bool lockdebug_ok);
 extern int test_taint(unsigned flag);
 extern unsigned long get_taint(void);
 extern int root_mountflags;
diff --git a/kernel/module.c b/kernel/module.c
index ec535aa..ce96df4 100644
--- a/kernel/module.c
+++ b/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,
+				    bool 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, false);
 	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, false);
 	return 0;
 #else
 	return -ENOEXEC;
@@ -2147,7 +2148,7 @@ 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, false);
 	}
 }
 
@@ -2700,10 +2701,10 @@ 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, true);
 
 	if (get_modinfo(info, "staging")) {
-		add_taint_module(mod, TAINT_CRAP);
+		add_taint_module(mod, TAINT_CRAP, true);
 		printk(KERN_WARNING "%s: module is from the staging directory,"
 		       " the quality is unknown, you have been warned.\n",
 		       mod->name);
@@ -2869,15 +2870,15 @@ 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, false);
 
 	/* 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, false);
 
 	/* 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, false);
 
 #ifdef CONFIG_MODVERSIONS
 	if ((mod->num_syms && !mod->crcs)
@@ -3170,7 +3171,7 @@ again:
 #ifdef CONFIG_MODULE_SIG
 	mod->sig_ok = info->sig_ok;
 	if (!mod->sig_ok)
-		add_taint_module(mod, TAINT_FORCED_MODULE);
+		add_taint_module(mod, TAINT_FORCED_MODULE, false);
 #endif
 
 	/* Now module is in final location, initialize linked lists, etc. */
diff --git a/kernel/panic.c b/kernel/panic.c
index e1b2822..92d38de 100644
--- a/kernel/panic.c
+++ b/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.
+ * @lockdebug_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, bool lockdebug_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 (!lockdebug_ok && __debug_locks_off())
+		printk(KERN_WARNING
+		       "Disabling lock debugging due to kernel taint\n");
 
 	set_bit(flag, &tainted_mask);
 }
@@ -421,7 +414,7 @@ static void warn_slowpath_common(const char *file, int line, void *caller,
 	print_modules();
 	dump_stack();
 	print_oops_end_marker();
-	add_taint(taint);
+	add_taint(taint, true); /* Just a warning, don't kill lockdep. */
 }
 
 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 257002c..dc05028 100644
--- a/kernel/sched/core.c
+++ b/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, true);
 }
 
 /*
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c88878d..7137a2d 100644
--- a/kernel/sysctl.c
+++ b/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, true);
 		}
 	}
 
diff --git a/lib/bug.c b/lib/bug.c
index d0cdf14..8d57bca 100644
--- a/lib/bug.c
+++ b/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), true);
 		return BUG_TRAP_TYPE_WARN;
 	}
 
diff --git a/mm/memory.c b/mm/memory.c
index bb1369f..8473e48 100644
--- a/mm/memory.c
+++ b/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, false);
 }
 
 static inline bool is_cow_mapping(vm_flags_t flags)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index df2022f..c978a3d 100644
--- a/mm/page_alloc.c
+++ b/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, false);
 }
 
 /*
diff --git a/mm/slab.c b/mm/slab.c
index e7667a3..f3e8bf2 100644
--- a/mm/slab.c
+++ b/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, false);
 }
 #endif
 
diff --git a/mm/slub.c b/mm/slub.c
index ba2ca53..786ed87 100644
--- a/mm/slub.c
+++ b/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, false);
 }
 
 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 91d592f..9ecbb53 100644
--- a/sound/soc/soc-core.c
+++ b/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, false);
 
 	snd_soc_write(codec, reg, value);
 	return buf_size;

Re: [PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Josh Boyer]

On Wed, Jan 16, 2013 at 02:04:50PM +1030, Rusty Russell wrote:
> Josh Boyer <jwboyer@redhat.com> writes:
> > With module signing enabled but not in enforcing mode, we don't consider
> > unsigned modules to be an error.  However, if we encounter an unsigned
> > module we currently taint the module and kernel with TAINT_FORCED_MODULE.
> > That also disables lockdep within the kernel.
> 
> How about this, instead?  Ingo?

That would work for me for the lockdep issue, sure.  I thought I'd make
the unsigned/wrong key module case a bit more clear at the same time.
Do you think that's worth doing aside from lockdep?  If so, and your
patch seems acceptable to others, I'd be happy to respin my patch on
top.

I'll give your patch a test in just a bit.

josh

Re: [PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Josh Boyer]

On Wed, Jan 16, 2013 at 02:04:50PM +1030, Rusty Russell wrote:
> Josh Boyer <jwboyer@redhat.com> writes:
> > With module signing enabled but not in enforcing mode, we don't consider
> > unsigned modules to be an error.  However, if we encounter an unsigned
> > module we currently taint the module and kernel with TAINT_FORCED_MODULE.
> > That also disables lockdep within the kernel.
> 
> How about this, instead?  Ingo?

<snip> 

> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index 86e2f4a..7acca64 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -230,7 +230,7 @@ dmar_parse_one_rhsa(struct acpi_dmar_header *header)
>  		}
>  	}
>  	WARN_TAINT(
> -		1, TAINT_FIRMWARE_WORKAROUND,
> +		1, TAINT_FIRMWARE_WORKAROUND, true,
>  		"Your BIOS is broken; RHSA refers to non-existent DMAR unit at %llx\n"
>  		"BIOS vendor: %s; Ver: %s; Product Version: %s\n",
>  		drhd->reg_base_addr,

This bit causes a build failure here:

drivers/iommu/dmar.c: In function 'dmar_parse_one_rhsa':
drivers/iommu/dmar.c:232:2: warning: passing argument 4 of 'warn_slowpath_fmt_taint' makes pointer from integer without a cast [enabled by default]
In file included from /home/jwboyer/kernel/kernel-3.7.fc19/linux-3.8.0-0.rc3.git2.2.2.fc19.x86_64/arch/x86/include/asm/bug.h:38:0,
                 from include/linux/bug.h:4,
                 from include/linux/cpumask.h:12,
                 from /home/jwboyer/kernel/kernel-3.7.fc19/linux-3.8.0-0.rc3.git2.2.2.fc19.x86_64/arch/x86/include/asm/cpumask.h:4,
                 from /home/jwboyer/kernel/kernel-3.7.fc19/linux-3.8.0-0.rc3.git2.2.2.fc19.x86_64/arch/x86/include/asm/msr.h:10,
                 from /home/jwboyer/kernel/kernel-3.7.fc19/linux-3.8.0-0.rc3.git2.2.2.fc19.x86_64/arch/x86/include/asm/processor.h:20,
                 from /home/jwboyer/kernel/kernel-3.7.fc19/linux-3.8.0-0.rc3.git2.2.2.fc19.x86_64/arch/x86/include/asm/atomic.h:6,
                 from include/linux/atomic.h:4,
                 from include/linux/debug_locks.h:5,
                 from include/linux/lockdep.h:23,
                 from include/linux/sysfs.h:18,
                 from include/linux/kobject.h:21,
                 from include/linux/pci.h:28,
                 from drivers/iommu/dmar.c:31:
include/asm-generic/bug.h:69:6: note: expected 'const char *' but argument is of type 'int'
drivers/iommu/intel-iommu.c:4287:23: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'quirk_ricoh_multifunction'
drivers/iommu/intel-iommu.c:4291:1: error: 'quirk_ricoh_multifunction' undeclared here (not in a function)
make[2]: *** [drivers/iommu/intel-iommu.o] Error 1

Looking at it, but the WARN_ macros are currently making my head hurt.

josh

Re: [PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Rusty Russell]

Josh Boyer <jwboyer@redhat.com> writes:
>> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
>> index 86e2f4a..7acca64 100644
>> --- a/drivers/iommu/dmar.c
>> +++ b/drivers/iommu/dmar.c
>> @@ -230,7 +230,7 @@ dmar_parse_one_rhsa(struct acpi_dmar_header *header)
>>  		}
>>  	}
>>  	WARN_TAINT(
>> -		1, TAINT_FIRMWARE_WORKAROUND,
>> +		1, TAINT_FIRMWARE_WORKAROUND, true,
>>  		"Your BIOS is broken; RHSA refers to non-existent DMAR unit at %llx\n"
>>  		"BIOS vendor: %s; Ver: %s; Product Version: %s\n",
>>  		drhd->reg_base_addr,
>
> This bit causes a build failure here:

Oops, that slipped in from a previous version, where I was going to
add the lockdep_ok flag to WARN().  I forgot to flip the module sig_ok
case, which was the entire point!

Here it is:

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>

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 272666d..2fca8ca 100644
--- a/arch/alpha/kernel/traps.c
+++ b/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, false);
 	dik_show_trace((unsigned long *)(regs+1));
 	dik_show_code((unsigned int *)regs->pc);
 
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index b0179b8..02d2e1a 100644
--- a/arch/arm/kernel/traps.c
+++ b/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, false);
 	die_nest_count--;
 	if (!die_nest_count)
 		/* Nest count reaches zero, release the lock. */
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 3883f84..d4fe267 100644
--- a/arch/arm64/kernel/traps.c
+++ b/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, false);
 	raw_spin_unlock_irq(&die_lock);
 	oops_exit();
 
diff --git a/arch/avr32/kernel/traps.c b/arch/avr32/kernel/traps.c
index 3d760c0..4c084d9 100644
--- a/arch/avr32/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 
 	if (in_interrupt())
diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
index a41eeb8..0637a86 100644
--- a/arch/hexagon/kernel/traps.c
+++ b/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, false);
 
 	spin_unlock_irq(&die.lock);
 
diff --git a/arch/ia64/kernel/traps.c b/arch/ia64/kernel/traps.c
index bd42b76..e4e71c5 100644
--- a/arch/ia64/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die.lock);
 
 	if (!regs)
diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index cbc624a..18798af 100644
--- a/arch/m68k/kernel/traps.c
+++ b/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, false);
 	do_exit(SIGSEGV);
 }
 
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index cf7ac54..a88f820 100644
--- a/arch/mips/kernel/traps.c
+++ b/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, false);
 	raw_spin_unlock_irq(&die_lock);
 
 	oops_exit();
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 45ba99f..614dc31 100644
--- a/arch/parisc/kernel/traps.c
+++ b/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, false);
 
 	if (in_interrupt())
 		panic("Fatal exception in interrupt");
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 3251840..ec875b8 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/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, false);
 	die_nest_count--;
 	oops_exit();
 	printk("\n");
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index 70ecfc5..09ff735 100644
--- a/arch/s390/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 	if (in_interrupt())
 		panic("Fatal exception in interrupt");
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index 72246bc..ae0759d 100644
--- a/arch/sh/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 	oops_exit();
 
diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c
index 0eaf005..269a0d5 100644
--- a/arch/sparc/kernel/setup_64.c
+++ b/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, false);
 		cheetah_enable_pcache();
 		break;
 
diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index a5785ea..13f09de 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/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, false);
 
 	__SAVE; __SAVE; __SAVE; __SAVE;
 	__SAVE; __SAVE; __SAVE; __SAVE;
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index e7ecf15..5db8b53 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/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, false);
 	if (regs->tstate & TSTATE_PRIV) {
 		struct thread_info *tp = current_thread_info();
 		struct reg_window *rw = (struct reg_window *)
diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c
index 2054f0d..2a2351b 100644
--- a/arch/unicore32/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 	oops_exit();
 
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 15239ff..b9d242f 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/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, false);
 
 valid_k7:
 	;
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 80dbda8..bc43a1f 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/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, false);
 
 		severity = mce_severity(&m, cfg->tolerant, NULL);
 
diff --git a/arch/x86/kernel/cpu/mcheck/p5.c b/arch/x86/kernel/cpu/mcheck/p5.c
index 2d5454c..544cdee 100644
--- a/arch/x86/kernel/cpu/mcheck/p5.c
+++ b/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, false);
 }
 
 /* Set up machine check reporting for processors with Intel style MCE: */
diff --git a/arch/x86/kernel/cpu/mcheck/winchip.c b/arch/x86/kernel/cpu/mcheck/winchip.c
index 2d7998f..6cb85e03a 100644
--- a/arch/x86/kernel/cpu/mcheck/winchip.c
+++ b/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, false);
 }
 
 /* Set up machine check reporting on the Winchip C6 series */
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index e9fe907..c00a664 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/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, true);
 			mask_lo = tmp;
 		}
 	}
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index ae42418b..7ad7830 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/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, false);
 	die_nest_count--;
 	if (!die_nest_count)
 		/* Nest count reaches zero, release the lock. */
diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index 01e0111..fc1bef8 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/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, false);
 	spin_unlock_irq(&die_lock);
 
 	if (in_interrupt())
diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c
index 5d42c24..000c701 100644
--- a/drivers/acpi/custom_method.c
+++ b/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, false);
 	}
 
 	return count;
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 3ff2678..15b803e 100644
--- a/drivers/acpi/osl.c
+++ b/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, false);
 }
 
 
diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 07aad78..32a5be2 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -232,7 +232,7 @@ 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, false);
 
 	regmap_write(map, reg, value);
 	return buf_size;
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index c566927..53c14cb 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -398,7 +398,7 @@ 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);
+extern void add_taint(unsigned flag, bool lockdebug_ok);
 extern int test_taint(unsigned flag);
 extern unsigned long get_taint(void);
 extern int root_mountflags;
diff --git a/kernel/module.c b/kernel/module.c
index ec535aa..ce96df4 100644
--- a/kernel/module.c
+++ b/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,
+				    bool 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, false);
 	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, false);
 	return 0;
 #else
 	return -ENOEXEC;
@@ -2147,7 +2148,7 @@ 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, false);
 	}
 }
 
@@ -2700,10 +2701,10 @@ 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, true);
 
 	if (get_modinfo(info, "staging")) {
-		add_taint_module(mod, TAINT_CRAP);
+		add_taint_module(mod, TAINT_CRAP, true);
 		printk(KERN_WARNING "%s: module is from the staging directory,"
 		       " the quality is unknown, you have been warned.\n",
 		       mod->name);
@@ -2869,15 +2870,15 @@ 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, false);
 
 	/* 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, false);
 
 	/* 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, false);
 
 #ifdef CONFIG_MODVERSIONS
 	if ((mod->num_syms && !mod->crcs)
@@ -3170,7 +3171,7 @@ again:
 #ifdef CONFIG_MODULE_SIG
 	mod->sig_ok = info->sig_ok;
 	if (!mod->sig_ok)
-		add_taint_module(mod, TAINT_FORCED_MODULE);
+		add_taint_module(mod, TAINT_FORCED_MODULE, true);
 #endif
 
 	/* Now module is in final location, initialize linked lists, etc. */
diff --git a/kernel/panic.c b/kernel/panic.c
index e1b2822..92d38de 100644
--- a/kernel/panic.c
+++ b/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.
+ * @lockdebug_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, bool lockdebug_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 (!lockdebug_ok && __debug_locks_off())
+		printk(KERN_WARNING
+		       "Disabling lock debugging due to kernel taint\n");
 
 	set_bit(flag, &tainted_mask);
 }
@@ -421,7 +414,7 @@ static void warn_slowpath_common(const char *file, int line, void *caller,
 	print_modules();
 	dump_stack();
 	print_oops_end_marker();
-	add_taint(taint);
+	add_taint(taint, true); /* Just a warning, don't kill lockdep. */
 }
 
 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 257002c..dc05028 100644
--- a/kernel/sched/core.c
+++ b/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, true);
 }
 
 /*
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c88878d..7137a2d 100644
--- a/kernel/sysctl.c
+++ b/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, true);
 		}
 	}
 
diff --git a/lib/bug.c b/lib/bug.c
index d0cdf14..8d57bca 100644
--- a/lib/bug.c
+++ b/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), true);
 		return BUG_TRAP_TYPE_WARN;
 	}
 
diff --git a/mm/memory.c b/mm/memory.c
index bb1369f..8473e48 100644
--- a/mm/memory.c
+++ b/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, false);
 }
 
 static inline bool is_cow_mapping(vm_flags_t flags)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index df2022f..c978a3d 100644
--- a/mm/page_alloc.c
+++ b/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, false);
 }
 
 /*
diff --git a/mm/slab.c b/mm/slab.c
index e7667a3..f3e8bf2 100644
--- a/mm/slab.c
+++ b/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, false);
 }
 #endif
 
diff --git a/mm/slub.c b/mm/slub.c
index ba2ca53..786ed87 100644
--- a/mm/slub.c
+++ b/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, false);
 }
 
 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 91d592f..9ecbb53 100644
--- a/sound/soc/soc-core.c
+++ b/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, false);
 
 	snd_soc_write(codec, reg, value);
 	return buf_size;

Re: [PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Dave Jones]

On Thu, Jan 17, 2013 at 11:27:27AM +1030, Rusty Russell wrote:
 
 > 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>
 
This made my brain itch a little until I got to the bottom of the
patch and saw the new definition of add_taint.  Perhaps instead of
false/true, we have LOCKDEP_LIVES/LOCKDEP_DIES or similar defines
to make it clearer what's actually happening without having to
go read the function ?

 > + * 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.
 > + */

'noteworthy'

	Dave

Re: [PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Frank Ch. Eigler]

Hi -

> [...]
> -	add_taint(TAINT_DIE);
> +	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
> [...]

If "UNRELIABLE" a good way to describe it - not DANGEROUS or
COUNTERPRODUCTIVE or something, then maybe lockdep *can* produce
reasonable results following such a taint.  If the results are merely
suspect, could lockdep reports include the taint report, but otherwise
keep working?

- FChE

Re: [PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Rusty Russell]

"Frank Ch. Eigler" <fche@redhat.com> writes:
> Hi -
>
>> [...]
>> -	add_taint(TAINT_DIE);
>> +	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
>> [...]
>
> If "UNRELIABLE" a good way to describe it - not DANGEROUS or
> COUNTERPRODUCTIVE or something, then maybe lockdep *can* produce
> reasonable results following such a taint.  If the results are merely
> suspect, could lockdep reports include the taint report, but otherwise
> keep working?

git blame is your friend here:

commit 2c16e9c888985761511bd1905b00fb271169c3c0
Author: Arjan van de Ven <arjan@linux.intel.com>
Date:   Mon Jul 10 04:45:42 2006 -0700

    [PATCH] lockdep: disable lock debugging when kernel state becomes untrusted
    
    Disable lockdep debugging in two situations where the integrity of the
    kernel no longer is guaranteed: when oopsing and when hitting a
    tainting-condition.  The goal is to not get weird lockdep traces that don't
    make sense or are otherwise undebuggable, to not waste time.
    
    Lockdep assumes that the previous state it knows about is valid to operate,
    which is why lockdep turns itself off after the first violation it reports,
    after that point it can no longer make that assumption.
    
    A kernel oops means that the integrity of the kernel compromised; in
    addition anything lockdep would report is of lesser importance than the
    oops.
    
    All the tainting conditions are of similar integrity-violating nature and
    also make debugging/diagnosing more difficult.
    
    Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Andrew Morton <akpm@osdl.org>
    Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Cheers,
Rusty.

Re: [PATCH] MODSIGN: Add TAINT_NOKEY_MODULE

[Rafael J. Wysocki]

On Monday, January 21, 2013 10:30:22 AM Rusty Russell wrote:
> Dave Jones <davej@redhat.com> writes:
> > On Thu, Jan 17, 2013 at 11:27:27AM +1030, Rusty Russell wrote:
> >  
> >  > 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>
> >  
> > This made my brain itch a little until I got to the bottom of the
> > patch and saw the new definition of add_taint.  Perhaps instead of
> > false/true, we have LOCKDEP_LIVES/LOCKDEP_DIES or similar defines
> > to make it clearer what's actually happening without having to
> > go read the function ?
> 
> The reason I didn't do that is because it's theoretically more than
> lockdep: it's anything which relies on kernel integrity.
> 
> Then I got the true/false thing mixed up myself, so I think you're right
> :)
> 
> BTW, ACPI people: those TAINT_OVERRIDDEN_ACPI_TABLE taints were
> disabling lockdep: is that overzealous?

I think so, although it's quite difficult to say what the intention was at
this point.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.