lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Make the taint flags reliable

Browse Source 
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>
This commit is contained in:
Andi Kleen
2008-10-15 22:01:41 -07:00
committed by Linus Torvalds
parent 889d51a107
commit 25ddbb18aa
6 changed files with 101 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
arch/x86/kernel/smpboot.c
View File

@ -282,6 +282,8 @@ static void __cpuinit smp_callin(void)
cpu_set(cpuid, cpu_callin_map);
}
static int __cpuinitdata unsafe_smp;
/*
* Activate a secondary processor.
*/
@ -397,7 +399,7 @@ static void __cpuinit smp_apply_quirks(struct cpuinfo_x86 *c)
goto valid_k7;
/* If we get here, not a certified SMP capable AMD system. */
add_taint(TAINT_UNSAFE_SMP);
unsafe_smp = 1;
}
valid_k7:
@ -414,12 +416,10 @@ static void __cpuinit smp_checks(void)
* Don't taint if we are running SMP kernel on a single non-MP
* approved Athlon
*/
if (tainted & TAINT_UNSAFE_SMP) {
if (num_online_cpus())
printk(KERN_INFO "WARNING: This combination of AMD"
"processors is not suitable for SMP.\n");
else
tainted &= ~TAINT_UNSAFE_SMP;
if (unsafe_smp && num_online_cpus() > 1) {
printk(KERN_INFO "WARNING: This combination of AMD"
"processors is not suitable for SMP.\n");
add_taint(TAINT_UNSAFE_SMP);
}
}