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Commit bd9cb64d authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
Browse files

[PATCH] x86_64: fix page fault from show_trace() 



The introduction of call_softirq switching to the interrupt stack several
releases earlier resulted in a problem with the code in show_trace, which
assumes that it can pick the previous stack pointer from the end of the
interrupt stack.

Cc: Andi Kleen <ak@muc.de>
Cc: Arjan van de Ven <arjanv@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 4724e3e8

arch/x86_64/kernel/entry.S

+5 −7
Original line number Diff line number Diff line
@@ -1045,17 +1045,15 @@ ENTRY(call_debug) 
ENTRY(call_softirq)

	CFI_STARTPROC

	movq %gs:pda_irqstackptr,%rax

	pushq %r15

	CFI_ADJUST_CFA_OFFSET 8

	movq %rsp,%r15

	CFI_DEF_CFA_REGISTER	r15

	movq %rsp,%rdx

	CFI_DEF_CFA_REGISTER	rdx

	incl %gs:pda_irqcount

	cmove %rax,%rsp

	pushq %rdx

	/*todo CFI_DEF_CFA_EXPRESSION ...*/

	call __do_softirq

	movq %r15,%rsp

	popq %rsp

	CFI_DEF_CFA_REGISTER	rsp

	decl %gs:pda_irqcount

	popq %r15

	CFI_ADJUST_CFA_OFFSET -8

	ret

	CFI_ENDPROC