From dbf520a9d7d4d5ba28d2947be11e34099a5e3e20 Mon Sep 17 00:00:00 2001 From: Paul Walmsley Date: Sun, 31 Mar 2013 00:04:40 +0000 Subject: Revert "lockdep: check that no locks held at freeze time" This reverts commit 6aa9707099c4b25700940eb3d016f16c4434360d. Commit 6aa9707099c4 ("lockdep: check that no locks held at freeze time") causes problems with NFS root filesystems. The failures were noticed on OMAP2 and 3 boards during kernel init: [ BUG: swapper/0/1 still has locks held! ] 3.9.0-rc3-00344-ga937536 #1 Not tainted ------------------------------------- 1 lock held by swapper/0/1: #0: (&type->s_umount_key#13/1){+.+.+.}, at: [] sget+0x248/0x574 stack backtrace: rpc_wait_bit_killable __wait_on_bit out_of_line_wait_on_bit __rpc_execute rpc_run_task rpc_call_sync nfs_proc_get_root nfs_get_root nfs_fs_mount_common nfs_try_mount nfs_fs_mount mount_fs vfs_kern_mount do_mount sys_mount do_mount_root mount_root prepare_namespace kernel_init_freeable kernel_init Although the rootfs mounts, the system is unstable. Here's a transcript from a PM test: http://www.pwsan.com/omap/testlogs/test_v3.9-rc3/20130317194234/pm/37xxevm/37xxevm_log.txt Here's what the test log should look like: http://www.pwsan.com/omap/testlogs/test_v3.8/20130218214403/pm/37xxevm/37xxevm_log.txt Mailing list discussion is here: http://lkml.org/lkml/2013/3/4/221 Deal with this for v3.9 by reverting the problem commit, until folks can figure out the right long-term course of action. Signed-off-by: Paul Walmsley Cc: Mandeep Singh Baines Cc: Jeff Layton Cc: Shawn Guo Cc: Cc: Fengguang Wu Cc: Trond Myklebust Cc: Ingo Molnar Cc: Ben Chan Cc: Oleg Nesterov Cc: Tejun Heo Cc: Rafael J. Wysocki Cc: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/lockdep.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'kernel/lockdep.c') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 259db207b5d9..8a0efac4f99d 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -4088,7 +4088,7 @@ void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) } EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); -static void print_held_locks_bug(void) +static void print_held_locks_bug(struct task_struct *curr) { if (!debug_locks_off()) return; @@ -4097,21 +4097,22 @@ static void print_held_locks_bug(void) printk("\n"); printk("=====================================\n"); - printk("[ BUG: %s/%d still has locks held! ]\n", - current->comm, task_pid_nr(current)); + printk("[ BUG: lock held at task exit time! ]\n"); print_kernel_ident(); printk("-------------------------------------\n"); - lockdep_print_held_locks(current); + printk("%s/%d is exiting with locks still held!\n", + curr->comm, task_pid_nr(curr)); + lockdep_print_held_locks(curr); + printk("\nstack backtrace:\n"); dump_stack(); } -void debug_check_no_locks_held(void) +void debug_check_no_locks_held(struct task_struct *task) { - if (unlikely(current->lockdep_depth > 0)) - print_held_locks_bug(); + if (unlikely(task->lockdep_depth > 0)) + print_held_locks_bug(task); } -EXPORT_SYMBOL_GPL(debug_check_no_locks_held); void debug_show_all_locks(void) { -- cgit v1.2.3