Make the taint flags reliable

It's somewhat unlikely that it happens, but right now a race window
between interrupts or machine checks or oopses could corrupt the tainted
bitmap because it is modified in a non atomic fashion.

Convert the taint variable to an unsigned long and use only atomic bit
operations on it.

Unfortunately this means the intvec sysctl functions cannot be used on it
anymore.

It turned out the taint sysctl handler could actually be simplified a bit
(since it only increases capabilities) so this patch actually removes
code.

[akpm@linux-foundation.org: remove unneeded include]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 12 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 75d81f157d2e..e971c55f45ac 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -235,9 +235,10 @@ extern int oops_in_progress;		/* If set, an oops, panic(), BUG() or die() is in
 extern int panic_timeout;
 extern int panic_on_oops;
 extern int panic_on_unrecovered_nmi;
-extern int tainted;
 extern const char *print_tainted(void);
-extern void add_taint(unsigned);
+extern void add_taint(unsigned flag);
+extern int test_taint(unsigned flag);
+extern unsigned long get_taint(void);
 extern int root_mountflags;
 
 /* Values used for system_state */
@@ -250,16 +251,16 @@ extern enum system_states {
         SYSTEM_SUSPEND_DISK,
 } system_state;
 
-#define TAINT_PROPRIETARY_MODULE        (1<<0)
-#define TAINT_FORCED_MODULE             (1<<1)
-#define TAINT_UNSAFE_SMP                (1<<2)
-#define TAINT_FORCED_RMMOD              (1<<3)
-#define TAINT_MACHINE_CHECK             (1<<4)
-#define TAINT_BAD_PAGE                  (1<<5)
-#define TAINT_USER                      (1<<6)
-#define TAINT_DIE                       (1<<7)
-#define TAINT_OVERRIDDEN_ACPI_TABLE     (1<<8)
-#define TAINT_WARN                      (1<<9)
+#define TAINT_PROPRIETARY_MODULE        0
+#define TAINT_FORCED_MODULE             1
+#define TAINT_UNSAFE_SMP                2
+#define TAINT_FORCED_RMMOD              3
+#define TAINT_MACHINE_CHECK             4
+#define TAINT_BAD_PAGE                  5
+#define TAINT_USER                      6
+#define TAINT_DIE                       7
+#define TAINT_OVERRIDDEN_ACPI_TABLE     8
+#define TAINT_WARN                      9
 
 extern void dump_stack(void) __cold;