From 4748cf2bdee373fba9cec3f1f7e95928ae21c100 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Sat, 23 Jul 2016 09:46:39 +0200 Subject: sched/debug: Make the "Preemption disabled at ..." message more useful This message is currently really useless since it always prints a value that comes from the printk() we just did, e.g.: BUG: sleeping function called from invalid context at mm/slab.h:388 in_atomic(): 0, irqs_disabled(): 0, pid: 31996, name: trinity-c1 Preemption disabled at:[] down_trylock+0x13/0x80 BUG: sleeping function called from invalid context at include/linux/freezer.h:56 in_atomic(): 0, irqs_disabled(): 0, pid: 31996, name: trinity-c1 Preemption disabled at:[] console_unlock+0x2f7/0x930 Here, both down_trylock() and console_unlock() is somewhere in the printk() path. We should save the value before calling printk() and use the saved value instead. That immediately reveals the offending callsite: BUG: sleeping function called from invalid context at mm/slab.h:388 in_atomic(): 0, irqs_disabled(): 0, pid: 14971, name: trinity-c2 Preemption disabled at:[] rhashtable_walk_start+0x46/0x150 Bug report: http://marc.info/?l=linux-netdev&m=146925979821849&w=2 Change-Id: I5b08294385a2ac625dbf28d1f18ffd164aedabe0 Signed-off-by: Vegard Nossum Cc: Andrew Morton Cc: Linus Torvalds Cc: Mike Galbraith Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rusty Russel Cc: Thomas Gleixner Signed-off-by: Ingo Molnar [mkhaja@codeaurora.org: Fix trivial merge conflict] Git-commit: d1c6d149cf04d6c7c3c3ebf4b66c82500cbcf6e1 Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Mohammed Khajapasha --- include/linux/sched.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index 3a7521064fe3..e32cab9fe290 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -3246,6 +3246,15 @@ static inline void cond_resched_rcu(void) #endif } +static inline unsigned long get_preempt_disable_ip(struct task_struct *p) +{ +#ifdef CONFIG_DEBUG_PREEMPT + return p->preempt_disable_ip; +#else + return 0; +#endif +} + /* * Does a critical section need to be broken due to another * task waiting?: (technically does not depend on CONFIG_PREEMPT, -- cgit v1.2.3