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Commit 0c88ee5b authored Sep 11, 2009 by Heiko Carstens Committed by Martin Schwidefsky Sep 11, 2009

[S390] Initialize __LC_THREAD_INFO early.



"lockdep: Fix backtraces" reveales a bug in early setup code: when
lockdep tries to save a stack backtrace before setup_arch has been
called the lowcore pointer for the current thread info pointer isn't
initialized yet.
However our save stack backtrace code relies on it. If the pointer
isn't initialized the saved backtrace will have zero entries.
lockdep however relies (correctly) on the fact that that cannot
happen.
A write access to some random memory region is the result.

Fix this by initializing the thread info pointer early.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

parent 50aa98ba

arch/s390/kernel/head31.S

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -24,6 +24,7 @@ startup_continue:
	# Setup stack		# Setup stack
	#		#
	l %r15,.Linittu-.LPG1(%r13)		l %r15,.Linittu-.LPG1(%r13)
			st %r15,__LC_THREAD_INFO # cache thread info in lowcore
	mvc __LC_CURRENT(4),__TI_task(%r15)		mvc __LC_CURRENT(4),__TI_task(%r15)
	ahi %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union+THREAD_SIZE		ahi %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union+THREAD_SIZE
	st %r15,__LC_KERNEL_STACK # set end of kernel stack		st %r15,__LC_KERNEL_STACK # set end of kernel stack

arch/s390/kernel/head64.S

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -92,6 +92,7 @@ startup_continue:
	# Setup stack		# Setup stack
	#		#
	larl %r15,init_thread_union		larl %r15,init_thread_union
			stg %r15,__LC_THREAD_INFO # cache thread info in lowcore
	lg %r14,__TI_task(%r15) # cache current in lowcore		lg %r14,__TI_task(%r15) # cache current in lowcore
	stg %r14,__LC_CURRENT		stg %r14,__LC_CURRENT
	aghi %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union + THREAD_SIZE		aghi %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union + THREAD_SIZE