Eric W. Biederman dfb2ea45be proc: Allow proc_free_inum to be called from any context ... While testing the pid namespace code I hit this nasty warning. [ 176.262617] ------------[ cut here ]------------ [ 176.263388] WARNING: at /home/eric/projects/linux/linux-userns-devel/kernel/softirq.c:160 local_bh_enable_ip+0x7a/0xa0() [ 176.265145] Hardware name: Bochs [ 176.265677] Modules linked in: [ 176.266341] Pid: 742, comm: bash Not tainted 3.7.0userns+ #18 [ 176.266564] Call Trace: [ 176.266564] [<ffffffff810a539f>] warn_slowpath_common+0x7f/0xc0 [ 176.266564] [<ffffffff810a53fa>] warn_slowpath_null+0x1a/0x20 [ 176.266564] [<ffffffff810ad9ea>] local_bh_enable_ip+0x7a/0xa0 [ 176.266564] [<ffffffff819308c9>] _raw_spin_unlock_bh+0x19/0x20 [ 176.266564] [<ffffffff8123dbda>] proc_free_inum+0x3a/0x50 [ 176.266564] [<ffffffff8111d0dc>] free_pid_ns+0x1c/0x80 [ 176.266564] [<ffffffff8111d195>] put_pid_ns+0x35/0x50 [ 176.266564] [<ffffffff810c608a>] put_pid+0x4a/0x60 [ 176.266564] [<ffffffff8146b177>] tty_ioctl+0x717/0xc10 [ 176.266564] [<ffffffff810aa4d5>] ? wait_consider_task+0x855/0xb90 [ 176.266564] [<ffffffff81086bf9>] ? default_spin_lock_flags+0x9/0x10 [ 176.266564] [<ffffffff810cab0a>] ? remove_wait_queue+0x5a/0x70 [ 176.266564] [<ffffffff811e37e8>] do_vfs_ioctl+0x98/0x550 [ 176.266564] [<ffffffff810b8a0f>] ? recalc_sigpending+0x1f/0x60 [ 176.266564] [<ffffffff810b9127>] ? __set_task_blocked+0x37/0x80 [ 176.266564] [<ffffffff810ab95b>] ? sys_wait4+0xab/0xf0 [ 176.266564] [<ffffffff811e3d31>] sys_ioctl+0x91/0xb0 [ 176.266564] [<ffffffff810a95f0>] ? task_stopped_code+0x50/0x50 [ 176.266564] [<ffffffff81939199>] system_call_fastpath+0x16/0x1b [ 176.266564] ---[ end trace 387af88219ad6143 ]--- It turns out that spin_unlock_bh(proc_inum_lock) is not safe when put_pid is called with another spinlock held and irqs disabled. For now take the easy path and use spin_lock_irqsave(proc_inum_lock) in proc_free_inum and spin_loc_irq in proc_alloc_inum(proc_inum_lock). Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>		2012-12-25 16:23:12 -08:00
..
array.c	Merge branch 'akpm' (Andrew's patch-bomb)	2012-12-17 20:58:12 -08:00
base.c	procfs: drop vmtruncate	2012-12-20 14:00:01 -05:00
cmdline.c
consoles.c	console: rename acquire/release_console_sem() to console_lock/unlock()	2011-01-26 10:50:06 +10:00
cpuinfo.c
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: Allow proc_free_inum to be called from any context	2012-12-25 16:23:12 -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
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
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	procfs: drop vmtruncate	2012-12-20 14:00:01 -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
vmcore.c	fadump: Introduce cleanup routine to invalidate /proc/vmcore.	2012-02-23 10:50:02 +11:00