x86: fix lockdep warning during suspend-to-ram
Andrew Morton wrote:
> I've been seeing the below for a long time during suspend-to-ram on the Vaio.
>
>
> PM: Syncing filesystems ... done.
> PM: Preparing system for mem sleep
> Freezing user space processes ... <4>------------[ cut here ]------------
> WARNING: at kernel/lockdep.c:2658 check_flags+0x4c/0x127()
> Modules linked in: i915 drm ipw2200 sonypi ipv6 autofs4 hidp l2cap bluetooth sunrpc nf_conntrack_netbios_ns ipt_REJECT nf_conntrack_ipv4 xt_state nf_conntrack xt_tcpudp iptable_filter ip_tables x_tables acpi_cpufreq nvram ohci1394 ieee1394 ehci_hcd uhci_hcd sg joydev snd_hda_intel snd_seq_dummy sr_mod snd_seq_oss cdrom snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss ieee80211 pcspkr ieee80211_crypt snd_pcm i2c_i801 snd_timer i2c_core ide_pci_generic piix snd soundcore snd_page_alloc button ext3 jbd ide_disk ide_core [last unloaded: ipw2200]
> Pid: 3250, comm: zsh Not tainted 2.6.26-rc5 #1
> [<c011c5f5>] warn_on_slowpath+0x41/0x6d
> [<c01080e6>] ? native_sched_clock+0x82/0x96
> [<c013789c>] ? mark_held_locks+0x41/0x5c
> [<c0315688>] ? _spin_unlock_irqrestore+0x36/0x58
> [<c0137a29>] ? trace_hardirqs_on+0xe6/0x10d
> [<c0138637>] ? __lock_acquire+0xae3/0xb2b
> [<c0313413>] ? schedule+0x39b/0x3b4
> [<c0135596>] check_flags+0x4c/0x127
> [<c01386b9>] lock_acquire+0x3a/0x86
> [<c0315075>] _spin_lock+0x26/0x53
> [<c0140660>] ? refrigerator+0x13/0xc3
> [<c0140660>] refrigerator+0x13/0xc3
> [<c012684a>] get_signal_to_deliver+0x3c/0x31e
> [<c0102fe7>] do_notify_resume+0x91/0x6ee
> [<c01359fd>] ? lock_release_holdtime+0x50/0x56
> [<c0315688>] ? _spin_unlock_irqrestore+0x36/0x58
> [<c0235d24>] ? read_chan+0x0/0x58c
> [<c0137a29>] ? trace_hardirqs_on+0xe6/0x10d
> [<c0315694>] ? _spin_unlock_irqrestore+0x42/0x58
> [<c0230afa>] ? tty_ldisc_deref+0x5c/0x63
> [<c0233104>] ? tty_read+0x66/0x98
> [<c014b3f0>] ? audit_syscall_exit+0x2aa/0x2c5
> [<c0109430>] ? do_syscall_trace+0x6b/0x16f
> [<c0103a9c>] work_notifysig+0x13/0x1b
> =======================
> ---[ end trace 25b49fe59a25afa5 ]---
> possible reason: unannotated irqs-off.
> irq event stamp: 58919
> hardirqs last enabled at (58919): [<c0103afd>] syscall_exit_work+0x11/0x26
Joy - I so love entry.S
Best I can make of it:
syscall_exit_work
resume_userspace
DISABLE_INTERRUPTS
(no TRACE_IRQS_OFF)
work_pending
work_notifysig
do_notify_resume()
do_signal()
get_signal_to_deliver()
try_to_freeze()
refrigerator()
task_lock() -> check_flags() -> BANG
The normal path is:
syscall_exit_work
resume_userspace
DISABLE_INTERRUPTS
restore_all
TRACE_IRQS_IRET
iret
No idea why that would not warn..
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 2a609dc..c778e4f 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -248,6 +248,7 @@
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
+ TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
# int/exception return?