The patch titled
kernel/printk.c: document possible deadlock against scheduler
has been removed from the -mm tree. Its filename was
kernel-printkc-document-possible-deadlock-against-scheduler.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: kernel/printk.c: document possible deadlock against scheduler
From: Jiri Kosina <jkosina@xxxxxxx>
kernel/printk.c: document possible deadlock against scheduler
The printk's comment states that it can be called from every context,
which might lead to false illusion that it could be called from everywhere
without any restrictions.
This is however not true - a call to printk() could deadlock if called from
scheduler code (namely from schedule(), wake_up(), etc) on runqueue lock
when it tries to wake up klogd. Document this.
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/printk.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN kernel/printk.c~kernel-printkc-document-possible-deadlock-against-scheduler kernel/printk.c
--- a/kernel/printk.c~kernel-printkc-document-possible-deadlock-against-scheduler
+++ a/kernel/printk.c
@@ -486,6 +486,9 @@ static int have_callable_console(void)
* @fmt: format string
*
* This is printk(). It can be called from any context. We want it to work.
+ * Be aware of the fact that if oops_in_progress is not set, we might try to
+ * wake klogd up which could deadlock on runqueue lock if printk() is called
+ * from scheduler code.
*
* We try to grab the console_sem. If we succeed, it's easy - we log the output and
* call the console drivers. If we fail to get the semaphore we place the output
_
Patches currently in -mm which might be from jkosina@xxxxxxx are
origin.patch
git-hid.patch
git-ipwireless_cs.patch
x86_64-fix-wrong-comment-regarding-set_fixmap.patch
some-kmalloc-memset-kzalloc-tree-wide.patch
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