The patch titled
Subject: lockdep: check that no locks held at freeze time
has been added to the -mm tree. Its filename is
lockdep-check-that-no-locks-held-at-freeze-time.patch
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From: Mandeep Singh Baines <msb@xxxxxxxxxxxx>
Subject: lockdep: check that no locks held at freeze time
We shouldn't try_to_freeze if locks are held. Verified that I get no
lockdep warnings after applying this patch and "vfork: don't
freezer_count() for in-kernel users of CLONE_VFORK".
Signed-off-by: Mandeep Singh Baines <msb@xxxxxxxxxxxx>
Cc: Ben Chan <benchan@xxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/freezer.h | 2 ++
kernel/lockdep.c | 6 +++---
2 files changed, 5 insertions(+), 3 deletions(-)
diff -puN include/linux/freezer.h~lockdep-check-that-no-locks-held-at-freeze-time include/linux/freezer.h
--- a/include/linux/freezer.h~lockdep-check-that-no-locks-held-at-freeze-time
+++ a/include/linux/freezer.h
@@ -3,6 +3,7 @@
#ifndef FREEZER_H_INCLUDED
#define FREEZER_H_INCLUDED
+#include <linux/debug_locks.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/atomic.h>
@@ -48,6 +49,7 @@ extern void thaw_kernel_threads(void);
static inline bool try_to_freeze(void)
{
+ debug_check_no_locks_held(current);
might_sleep();
if (likely(!freezing(current)))
return false;
diff -puN kernel/lockdep.c~lockdep-check-that-no-locks-held-at-freeze-time kernel/lockdep.c
--- a/kernel/lockdep.c~lockdep-check-that-no-locks-held-at-freeze-time
+++ a/kernel/lockdep.c
@@ -4098,10 +4098,10 @@ static void print_held_locks_bug(struct
return;
printk("\n");
- printk("=====================================\n");
- printk("[ BUG: lock held at task exit time! ]\n");
+ printk("=======================================\n");
+ printk("[ BUG: lock held at exit/freeze time! ]\n");
print_kernel_ident();
- printk("-------------------------------------\n");
+ printk("---------------------------------------\n");
printk("%s/%d is exiting with locks still held!\n",
curr->comm, task_pid_nr(curr));
lockdep_print_held_locks(curr);
_
Patches currently in -mm which might be from msb@xxxxxxxxxxxx are
vfork-dont-freezer_count-for-in-kernel-users-of-clone_vfork.patch
lockdep-check-that-no-locks-held-at-freeze-time.patch
coredump-cleanup-the-waiting-for-coredump_finish-code.patch
coredump-use-a-freezable_schedule-for-the-coredump_finish-wait.patch
coredump-abort-core-dump-piping-only-due-to-a-fatal-signal.patch
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