From: "Steven Rostedt (Red Hat)" <[email protected]> Commit 2223f6f6eeaa "x86: Clean up dumpstack_64.c code" moved the used variable to a local within the loop, but the in_exception_stack() depended on being non-volatile with the ability to change it.
By always re-initializing the "used" variable to zero, it would cause the in_exception_stack() to return the same thing each time, and cause the dump_stack loop to go into an infinite loop. Reported-by: Linus Torvalds <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- arch/x86/kernel/dumpstack_64.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 346b1df..74c262a 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -115,19 +115,18 @@ enum stack_type { }; static enum stack_type -analyze_stack(int cpu, struct task_struct *task, - unsigned long *stack, unsigned long **stack_end, char **id) +analyze_stack(int cpu, struct task_struct *task, unsigned long *stack, + unsigned long **stack_end, unsigned *used, char **id) { unsigned long *irq_stack; unsigned long addr; - unsigned used = 0; addr = ((unsigned long)stack & (~(THREAD_SIZE - 1))); if ((unsigned long)task_stack_page(task) == addr) return STACK_IS_NORMAL; *stack_end = in_exception_stack(cpu, (unsigned long)stack, - &used, id); + used, id); if (*stack_end) return STACK_IS_EXCEPTION; @@ -158,6 +157,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs, struct thread_info *tinfo; unsigned long *irq_stack; unsigned long dummy; + unsigned used = 0; int graph = 0; int done = 0; @@ -186,7 +186,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs, enum stack_type stype; char *id; - stype = analyze_stack(cpu, task, stack, &stack_end, &id); + stype = analyze_stack(cpu, task, stack, &stack_end, &used, &id); /* Default finish unless specified to continue */ done = 1; -- 1.8.5.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
