Skip to main content

Browse the archive

https://github.com/torvalds/linux
05 April 2024, 19:05:47 UTC
Revision 84477336ec03f8061ffd6908da341e063e5d6d1f authored by Borislav Petkov on 09 March 2016, 20:56:22 UTC, committed by Ingo Molnar on 10 March 2016, 10:27:12 UTC 
x86/delay: Avoid preemptible context checks in delay_mwaitx()
 
We do use this_cpu_ptr(&cpu_tss) as a cacheline-aligned, seldomly
accessed per-cpu var as the MONITORX target in delay_mwaitx(). However,
when called in preemptible context, this_cpu_ptr -> smp_processor_id() ->
debug_smp_processor_id() fires:

  BUG: using smp_processor_id() in preemptible [00000000] code: udevd/312
  caller is delay_mwaitx+0x40/0xa0

But we don't care about that check - we only need cpu_tss as a MONITORX
target and it doesn't really matter which CPU's var we're touching as
we're going idle anyway. Fix that.

Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: spg_linux_kernel@amd.com
Link: http://lkml.kernel.org/r/20160309205622.GG6564@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent a65050c
History
Tip revision: 84477336ec03f8061ffd6908da341e063e5d6d1f authored by Borislav Petkov on 09 March 2016, 20:56:22 UTC
x86/delay: Avoid preemptible context checks in delay_mwaitx()
Tip revision: 8447733
File Mode Size
Documentation
arch
block
certs
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.get_maintainer.ignore -rw-r--r-- 31 bytes
.gitignore -rw-r--r-- 1.2 KB
.mailmap -rw-r--r-- 5.5 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 95.4 KB
Kbuild -rw-r--r-- 2.6 KB
Kconfig -rw-r--r-- 252 bytes
MAINTAINERS -rw-r--r-- 337.7 KB
Makefile -rw-r--r-- 53.7 KB
README -rw-r--r-- 18.2 KB
REPORTING-BUGS -rw-r--r-- 7.3 KB

README

back to top