Xiaotian Feng ee297209bf proc: fix inconsistent lock state ... Lockdep found an inconsistent lock state when rcu is processing delayed work in softirq. Currently, kernel is using spin_lock/spin_unlock to protect proc_inum_ida, but proc_free_inum is called by rcu in softirq context. Use spin_lock_bh/spin_unlock_bh fix following lockdep warning. ================================= [ INFO: inconsistent lock state ] 3.7.0 #36 Not tainted --------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes: (proc_inum_lock){+.?...}, at: proc_free_inum+0x1c/0x50 {SOFTIRQ-ON-W} state was registered at: __lock_acquire+0x8ae/0xca0 lock_acquire+0x199/0x200 _raw_spin_lock+0x41/0x50 proc_alloc_inum+0x4c/0xd0 alloc_mnt_ns+0x49/0xc0 create_mnt_ns+0x25/0x70 mnt_init+0x161/0x1c7 vfs_caches_init+0x107/0x11a start_kernel+0x348/0x38c x86_64_start_reservations+0x131/0x136 x86_64_start_kernel+0x103/0x112 irq event stamp: 2993422 hardirqs last enabled at (2993422): _raw_spin_unlock_irqrestore+0x55/0x80 hardirqs last disabled at (2993421): _raw_spin_lock_irqsave+0x29/0x70 softirqs last enabled at (2993394): _local_bh_enable+0x13/0x20 softirqs last disabled at (2993395): call_softirq+0x1c/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(proc_inum_lock); <Interrupt> lock(proc_inum_lock); *** DEADLOCK *** no locks held by swapper/1/0. stack backtrace: Pid: 0, comm: swapper/1 Not tainted 3.7.0 #36 Call Trace: <IRQ> [<ffffffff810a40f1>] ? vprintk_emit+0x471/0x510 print_usage_bug+0x2a5/0x2c0 mark_lock+0x33b/0x5e0 __lock_acquire+0x813/0xca0 lock_acquire+0x199/0x200 _raw_spin_lock+0x41/0x50 proc_free_inum+0x1c/0x50 free_pid_ns+0x1c/0x50 put_pid_ns+0x2e/0x50 put_pid+0x4a/0x60 delayed_put_pid+0x12/0x20 rcu_process_callbacks+0x462/0x790 __do_softirq+0x1b4/0x3b0 call_softirq+0x1c/0x30 do_softirq+0x59/0xd0 irq_exit+0x54/0xd0 smp_apic_timer_interrupt+0x95/0xa3 apic_timer_interrupt+0x72/0x80 cpuidle_enter_tk+0x10/0x20 cpuidle_enter_state+0x17/0x50 cpuidle_idle_call+0x287/0x520 cpu_idle+0xba/0x130 start_secondary+0x2b3/0x2bc Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2012-12-20 17:40:20 -08:00
..
array.c	Merge branch 'akpm' (Andrew's patch-bomb)	2012-12-17 20:58:12 -08:00
base.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2012-12-17 15:44:47 -08:00
cmdline.c	proc: switch /proc/cmdline to seq_file	2008-10-23 14:29:04 +04:00
consoles.c	console: rename acquire/release_console_sem() to console_lock/unlock()	2011-01-26 10:50:06 +10:00
cpuinfo.c	proc: move /proc/cpuinfo code to fs/proc/cpuinfo.c	2008-10-23 15:05:11 +04:00
devices.c	proc: use seq_puts()/seq_putc() where possible	2011-01-13 08:03:16 -08:00
fd.c	procfs: add ability to plug in auxiliary fdinfo providers	2012-12-17 17:15:27 -08:00
fd.h	procfs: Move /proc/pid/fd[info] handling code to fd.[ch]	2012-09-26 21:10:01 -04:00
generic.c	proc: fix inconsistent lock state	2012-12-20 17:40:20 -08:00
inode.c	proc: Fix the namespace inode permission checks.	2012-11-20 04:19:48 -08:00
internal.h	procfs: Use the proc generic infrastructure for proc/self.	2012-11-19 03:09:34 -08:00
interrupts.c	proc: move /proc/interrupts boilerplate code to fs/proc/interrupts.c	2008-10-23 15:15:46 +04:00
Kconfig	kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT	2011-01-20 17:02:05 -08:00
kcore.c	procfs: use N_MEMORY instead N_HIGH_MEMORY	2012-12-12 17:38:32 -08:00
kmsg.c	procfs: Use generic_file_llseek in /proc/kmsg	2010-04-09 16:35:41 +02:00
loadavg.c	sched, timers: cleanup avenrun users	2009-05-15 15:32:45 +02:00
Makefile	procfs: Use the proc generic infrastructure for proc/self.	2012-11-19 03:09:34 -08:00
meminfo.c	fs/proc/meminfo.c: fix compilation error	2011-12-09 07:50:28 -08:00
mmu.c	fs/proc/mmu.c: headers butchery	2007-10-17 08:42:48 -07:00
namespaces.c	proc: Usable inode numbers for the namespace file descriptors.	2012-11-20 04:19:49 -08:00
nommu.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
page.c	kpageflags: fix wrong KPF_THP on non-huge compound pages	2012-10-09 16:23:00 +09:00
proc_devtree.c	procfs: use kbasename()	2012-12-17 17:15:17 -08:00
proc_net.c	stop passing nameidata to ->lookup()	2012-07-14 16:34:32 +04:00
proc_sysctl.c	sysctl: Pass useful parameters to sysctl permissions	2012-11-18 20:30:55 -05:00
proc_tty.c	proc: use seq_puts()/seq_putc() where possible	2011-01-13 08:03:16 -08:00
root.c	userns: Allow unprivilged mounts of proc and sysfs	2012-11-20 04:19:18 -08:00
self.c	procfs: Use the proc generic infrastructure for proc/self.	2012-11-19 03:09:34 -08:00
softirqs.c	proc: use seq_puts()/seq_putc() where possible	2011-01-13 08:03:16 -08:00
stat.c	nohz: Fix idle ticks in cpu summary line of /proc/stat	2012-10-10 14:05:21 +02:00
task_mmu.c	procfs: add VmFlags field in smaps output	2012-12-17 17:15:22 -08:00
task_nommu.c	proc: remove mm_for_maps()	2012-05-31 17:49:28 -07:00
uptime.c	Merge branch 'sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into cputime-tip	2011-12-19 19:23:15 +01:00
version.c	proc: switch /proc/version to seq_file	2008-10-23 14:19:58 +04:00
vmcore.c	fadump: Introduce cleanup routine to invalidate /proc/vmcore.	2012-02-23 10:50:02 +11:00