Commit-ID: 0f1ba9a2cea52896448ef4e14a4cb1880b8e5bee
Gitweb: http://git.kernel.org/tip/0f1ba9a2cea52896448ef4e14a4cb1880b8e5bee
Author: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
AuthorDate: Wed, 7 Jan 2015 10:04:41 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 14 Jan 2015 15:16:21 +0100
softirq/preempt: Add missing current->preempt_disable_ip update
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@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20150107090441.GC4365@osiris
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/softirq.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 501baa9..b9ae816 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -114,8 +114,12 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
trace_softirqs_off(ip);
raw_local_irq_restore(flags);
- if (preempt_count() == cnt)
+ if (preempt_count() == cnt) {
+#ifdef CONFIG_DEBUG_PREEMPT
+ current->preempt_disable_ip = get_parent_ip(CALLER_ADDR1);
+#endif
trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
+ }
}
EXPORT_SYMBOL(__local_bh_disable_ip);
#endif /* CONFIG_TRACE_IRQFLAGS */
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|