Messages in this thread Patch in this message | | | Date | Wed, 7 Jan 2015 10:04:41 +0100 | From | Heiko Carstens <> | Subject | [PATCH/resend] softirq/preempt: add missing current->preempt_disable_ip update |
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While debugging some "sleeping function called from invalid context" bug I realized that the debugging message "Preemption disabled at:" pointed to an incorrect function. In particular if the last function/action that disabled preemption was spin_lock_bh() then current->preempt_disable_ip won't be updated.
The reason for this is that __local_bh_disable_ip() will increase preempt_count manually instead of calling preempt_count_add(), which would handle the update correctly. It look like the manual handling was done to work around some lockdep issue.
So add the missing update of current->preempt_disable_ip to __local_bh_disable_ip() as well.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> --- kernel/softirq.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c index 501baa9ac1be..edd51027e3ab 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -114,8 +114,13 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt) trace_softirqs_off(ip); raw_local_irq_restore(flags); - if (preempt_count() == cnt) - trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); + if (preempt_count() == cnt) { + unsigned long ip = get_parent_ip(CALLER_ADDR1); +#ifdef CONFIG_DEBUG_PREEMPT + current->preempt_disable_ip = ip; +#endif + trace_preempt_off(CALLER_ADDR0, ip); + } } EXPORT_SYMBOL(__local_bh_disable_ip); #endif /* CONFIG_TRACE_IRQFLAGS */ -- 1.8.5.5
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