mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

[PATCH] x86_64: Fix race in TSC synchronization 

Plug a race in TSC synchronization

We need to do tsc_sync_wait() before the CPU is set online to prevent
multiple CPUs from doing it in parallel - which won't work because TSC
sync has global unprotected state.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2005-08-19 06:56:40 +02:00 committed by Linus Torvalds
parent 5e5ec10499
commit 1eecd73cce
1 changed files with 8 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
arch/x86_64/kernel/smpboot.c
View File

@ -492,6 +492,14 @@ void __cpuinit start_secondary(void)
*/
set_cpu_sibling_map(smp_processor_id());
/*
* Wait for TSC sync to not schedule things before.
* We still process interrupts, which could see an inconsistent
* time in that window unfortunately.
* Do this here because TSC sync has global unprotected state.
*/
tsc_sync_wait();
/*
* We need to hold call_lock, so there is no inconsistency
* between the time smp_call_function() determines number of
@ -509,13 +517,6 @@ void __cpuinit start_secondary(void)
per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
unlock_ipi_call_lock();
mb();
/* Wait for TSC sync to not schedule things before.
We still process interrupts, which could see an inconsistent
time in that window unfortunately. */
tsc_sync_wait();
cpu_idle();
}