linux_dsm_epyc7002/include
Thomas Gleixner 7285dd7fd3 clocksource: Resolve cpu hotplug dead lock with TSC unstable
Martin Schwidefsky analyzed it:
To register a clocksource the clocksource_mutex is acquired and if
necessary timekeeping_notify is called to install the clocksource as
the timekeeper clock. timekeeping_notify uses stop_machine which needs
to take cpu_add_remove_lock mutex.
Starting a new cpu is done with the cpu_add_remove_lock mutex held.
native_cpu_up checks the tsc of the new cpu and if the tsc is no good
clocksource_change_rating is called. Which needs the clocksource_mutex
and the deadlock is complete.

The solution is to replace the TSC via the clocksource watchdog
mechanism. Mark the TSC as unstable and schedule the watchdog work so
it gets removed in the watchdog thread context.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
2009-08-28 20:25:24 +02:00
..
acpi Revert "ACPICA: Remove obsolete acpi_os_validate_address interface" 2009-07-27 18:42:38 -04:00
asm-generic mm: Pass virtual address to [__]p{te,ud,md}_free_tlb() 2009-07-27 12:10:38 -07:00
crypto
drm drm/radeon: Add support for RS880 chips 2009-08-05 12:07:09 +10:00
keys
linux clocksource: Resolve cpu hotplug dead lock with TSC unstable 2009-08-28 20:25:24 +02:00
math-emu
media V4L/DVB (12283): gspca - sn9c20x: New subdriver for sn9c201 and sn9c202 bridges. 2009-07-24 14:03:30 -03:00
mtd Kill jffs2-user.h 2009-06-05 17:31:38 +01:00
net Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2009-08-03 19:05:50 -07:00
pcmcia
rdma
rxrpc
scsi sd, sr: fix Driver 'sd' needs updating message 2009-06-21 12:01:27 -05:00
sound Merge branch 'topic/pcm-jiffies-check' into for-linus 2009-06-10 07:26:41 +02:00
trace perf_counter: Zero dead bytes from ftrace raw samples size alignment 2009-08-10 16:51:19 +02:00
video fbdev: s1d13xxxfb: add accelerated bitblt functions 2009-06-16 19:48:00 -07:00
xen
Kbuild [SCSI] FC Pass Thru support 2009-06-12 14:20:05 -05:00