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authorAndi Kleen <ak@suse.de>2006-08-02 22:37:28 +0200
committerLinus Torvalds <torvalds@g5.osdl.org>2006-08-02 20:19:54 -0700
commit2699500b31f41fc25656c42548c8a388c8a329fe (patch)
tree6f7ccd0318b9e53394cb276819f2d358ce933afa /arch
parentae74c3b69a08e1de20cb681ec959f3a48af0006a (diff)
[PATCH] x86_64: Fix backtracing for interrupt stacks
Re-add backlink for old style unwinder to stack switching. Add proper stack frame and CFI annotations to call_softirq This prevents a oops when backtracing with fallback through the interrupt stack top. Suggested by Jan Beulich and Herbert Xu wanted it in 2.6.18. Cc: jbeulich@novell.com Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86_64/kernel/entry.S18
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index d464dded68c..6f810424df4 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -513,6 +513,7 @@ END(stub_rt_sigreturn)
swapgs
1: incl %gs:pda_irqcount # RED-PEN should check preempt count
cmoveq %gs:pda_irqstackptr,%rsp
+ push %rbp # backlink for old unwinder
/*
* We entered an interrupt context - irqs are off:
*/
@@ -1139,18 +1140,21 @@ ENTRY(machine_check)
END(machine_check)
#endif
+/* Call softirq on interrupt stack. Interrupts are off. */
ENTRY(call_softirq)
CFI_STARTPROC
- movq %gs:pda_irqstackptr,%rax
- movq %rsp,%rdx
- CFI_DEF_CFA_REGISTER rdx
+ push %rbp
+ CFI_ADJUST_CFA_OFFSET 8
+ CFI_REL_OFFSET rbp,0
+ mov %rsp,%rbp
+ CFI_DEF_CFA_REGISTER rbp
incl %gs:pda_irqcount
- cmove %rax,%rsp
- pushq %rdx
- /*todo CFI_DEF_CFA_EXPRESSION ...*/
+ cmove %gs:pda_irqstackptr,%rsp
+ push %rbp # backlink for old unwinder
call __do_softirq
- popq %rsp
+ leaveq
CFI_DEF_CFA_REGISTER rsp
+ CFI_ADJUST_CFA_OFFSET -8
decl %gs:pda_irqcount
ret
CFI_ENDPROC