BUG: spinlock bad magic on CPU#0, setserial/3527

2.6.27-git-a447c093244 In review Rafael J. Wysocki 4 participants 5 messages Oct 13, 2008 – Oct 14, 2008

Share & tools

Alan Cox

2008-10-13 22:51 UTC #1 lore raw

Quoted 7 lines · On Tue, 14 Oct 2008 00:05:39 +0200 "Rafael J. Wysocki" <[email protected]> wrote:

Hi,
The Linus' tree from today on Asus L5D:
BUG: spinlock bad magic on CPU#0, setserial/3527
 lock: ffffffff80dae020, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
Pid: 3527, comm: setserial Not tainted 2.6.27-git #57

Yep looking at that at the moment. Its a fallout from dropping the NR_IRQ removal changes from the serial tree just before merging I think. Was done to make life simpler for Ingo's code push but appears to have slightly backfired.

Alan

Ingo Molnar

2008-10-14 06:56 UTC #2 lore raw

Quoted 7 lines · Alan Cox

Quoted 4 lines · On Tue, 14 Oct 2008 00:05:39 +0200 "Rafael J. Wysocki" <[email protected]> wrote:
Hi,
The Linus' tree from today on Asus L5D:

Quoted 8 lines

Quoted 3 lines
BUG: spinlock bad magic on CPU#0, setserial/3527
 lock: ffffffff80dae020, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
Pid: 3527, comm: setserial Not tainted 2.6.27-git #57
Yep looking at that at the moment. Its a fallout from dropping the NR_IRQ removal changes from the serial tree just before merging I think. Was done to make life simpler for Ingo's code push but appears to have slightly backfired.

i too have triggered it:

[   31.099528] BUG: spinlock bad magic on CPU#1, agetty/2608
[   31.101013]  lock: ffffffff8182b020, .magic: 00000000, .owner: agetty/2608, .owner_cpu: 1
[   31.101013] Pid: 2608, comm: agetty Not tainted 2.6.27-tip-03409-g064a754-dirty #42476
[   31.101013] Call Trace:
[   31.101013]  [<ffffffff8041ee15>] spin_bug+0xa2/0xaa
[   31.101013]  [<ffffffff8041ee3e>] _raw_spin_unlock+0x21/0x8a
[   31.101013]  [<ffffffff8089aac5>] _spin_unlock_irq+0x2b/0x36
[   31.101013]  [<ffffffff804a9a7b>] serial8250_startup+0x3f2/0x5a3
[   31.101013]  [<ffffffff804a5b00>] uart_startup+0xa0/0x14b
[   31.101013]  [<ffffffff804a6a5a>] uart_open+0x1a8/0x3f7
[   31.101013]  [<ffffffff8089aafb>] ? _spin_unlock+0x2b/0x2f
[   31.101013]  [<ffffffff8047ec6a>] tty_open+0x2db/0x41c
[   31.101013]  [<ffffffff802ac383>] chrdev_open+0x130/0x151
[   31.101013]  [<ffffffff8089aafb>] ? _spin_unlock+0x2b/0x2f
[   31.101013]  [<ffffffff802ac253>] ? chrdev_open+0x0/0x151
[   31.101013]  [<ffffffff802a7e38>] __dentry_open+0x178/0x274
[   31.101013]  [<ffffffff802a7f67>] nameidata_to_filp+0x33/0x44
[   31.101013]  [<ffffffff802b43df>] do_filp_open+0x3be/0x753
[   31.101013]  [<ffffffff802beb11>] ? alloc_fd+0x101/0x110
[   31.101013]  [<ffffffff8027d9c9>] ? trace_hardirqs_off+0x1e/0x20
[   31.101013]  [<ffffffff8089aafb>] ? _spin_unlock+0x2b/0x2f
[   31.101013]  [<ffffffff802beb11>] ? alloc_fd+0x101/0x110
[   31.101013]  [<ffffffff802a7bce>] do_sys_open+0x58/0xdf
[   31.101013]  [<ffffffff802a7c88>] sys_open+0x20/0x22
[   31.101013]  [<ffffffff8020c1cb>] system_call_fastpath+0x16/0x1b
[   31.405014] eth1: no IPv6 routers present
[   32.947611] ACPI: PCI Interrupt Link [APC3] enabled at IRQ 18

can test any patch for you if it's not easy to reproduce there.

Ingo

Ingo Molnar

2008-10-14 10:23 UTC #3 lore raw

PATCH 1/1 serial: fix serial port lock init

Quoted 2 lines

[   31.099528] BUG: spinlock bad magic on CPU#1, agetty/2608

the patch below fixes this. There's another incarnation of the bug that i bisected today, a spontaneous reboot crash with certain configs:

| b70ac7718579b5cbf3bdd74fd01132d1c91596f4 is first bad commit
| commit b70ac7718579b5cbf3bdd74fd01132d1c91596f4
| Author: David Miller <[email protected]>
| Date:   Mon Oct 13 10:36:31 2008 +0100
|
|     serial: allow 8250 to be used on sparc

# bad: [e7f2f991] Merge phase #5 (misc) of git://git.kernel.org/pub/
# good: [3fa8749e] Linux 2.6.27
# good: [4dd9ec49] Merge git://git.kernel.org/pub/scm/linux/kernel/gi
# good: [5c3c4d9b] Merge git://git.kernel.org/pub/scm/linux/kernel/gi
# good: [1a2217a9] Merge git://git.kernel.org/pub/scm/linux/kernel/gi
# good: [cf81978d] i386: convert hardware exception 15 to an interrup # good: [c00193f9] Merge branches 'oprofile-v2' and 'timers/hpet' int # bad: [8f520021] tty: Termios locking - sort out real_tty confusion # good: [f1ddfd95] ip2: init/deinit cleanup
# bad: [b70ac771] serial: allow 8250 to be used on sparc # good: [9bde10a4] serial-make-uart_ports-ioport-unsigned-long-fix # good: [43b11d33] ftdi: A few errors are err() that should be debug # good: [b5d674ab] 8250: remove a few inlines of dubious value

( but it's the same basic problem: we lost the lock init sequence when a
patch was removed from the middle. )

Ingo

----------------->

Quoted 1 line

From b15be1e63d0df3a1b4a25e7a28cfca9f93690884 Mon Sep 17 00:00:00 2001

From: Ingo Molnar <[email protected]>
Date: Tue, 14 Oct 2008 12:14:17 +0200
Subject: [PATCH] serial: fix serial port lock init

Signed-off-by Ingo Molnar <[email protected]>

---
 drivers/serial/8250.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

drivers/serial/8250.c +3 -0

index d4104a3..d3ca7d3 100644
@@ -2969,6 +2969,9 @@ static int __init serial8250_init(void)
 		"%d ports, IRQ sharing %sabled\n", nr_uarts,
 		share_irqs ? "en" : "dis");
 
+	for (i = 0; i < NR_IRQS; i++)
+		spin_lock_init(&irq_lists[i].lock);
+
 #ifdef CONFIG_SPARC
 	ret = sunserial_register_minors(&serial8250_reg, UART_NR);
 #else

Kamalesh Babulal

Tested-by on v1 1/1

2008-10-14 11:41 UTC #4 lore raw

Re: [PATCH] serial: fix serial port lock init

Quoted 30 lines · Ingo Molnar

Quoted 2 lines
[   31.099528] BUG: spinlock bad magic on CPU#1, agetty/2608
the patch below fixes this. There's another incarnation of the bug that i bisected today, a spontaneous reboot crash with certain configs:
| b70ac7718579b5cbf3bdd74fd01132d1c91596f4 is first bad commit
| commit b70ac7718579b5cbf3bdd74fd01132d1c91596f4
| Author: David Miller <[email protected]>
| Date:   Mon Oct 13 10:36:31 2008 +0100
|
|     serial: allow 8250 to be used on sparc
# bad: [e7f2f991] Merge phase #5 (misc) of git://git.kernel.org/pub/
# good: [3fa8749e] Linux 2.6.27
# good: [4dd9ec49] Merge git://git.kernel.org/pub/scm/linux/kernel/gi
# good: [5c3c4d9b] Merge git://git.kernel.org/pub/scm/linux/kernel/gi
# good: [1a2217a9] Merge git://git.kernel.org/pub/scm/linux/kernel/gi
# good: [cf81978d] i386: convert hardware exception 15 to an interrup # good: [c00193f9] Merge branches 'oprofile-v2' and 'timers/hpet' int # bad: [8f520021] tty: Termios locking - sort out real_tty confusion # good: [f1ddfd95] ip2: init/deinit cleanup
# bad: [b70ac771] serial: allow 8250 to be used on sparc # good: [9bde10a4] serial-make-uart_ports-ioport-unsigned-long-fix # good: [43b11d33] ftdi: A few errors are err() that should be debug # good: [b5d674ab] 8250: remove a few inlines of dubious value
( but it's the same basic problem: we lost the lock init sequence when a
patch was removed from the middle. )

Quoted 8 lines

Ingo
----------------->
From b15be1e63d0df3a1b4a25e7a28cfca9f93690884 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <[email protected]>
Date: Tue, 14 Oct 2008 12:14:17 +0200
Subject: [PATCH] serial: fix serial port lock init

Thanks, the patch fixes the warning.

Tested-by Kamalesh Babulal <[email protected]>

Quoted 20 lines

Signed-off-by Ingo Molnar <[email protected]>

---
 drivers/serial/8250.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

drivers/serial/8250.c +3 -0

index d4104a3..d3ca7d3 100644
@@ -2969,6 +2969,9 @@ static int __init serial8250_init(void)
 		"%d ports, IRQ sharing %sabled\n", nr_uarts,
 		share_irqs ? "en" : "dis");
 
+	for (i = 0; i < NR_IRQS; i++)
+		spin_lock_init(&irq_lists[i].lock);
+
 #ifdef CONFIG_SPARC
 	ret = sunserial_register_minors(&serial8250_reg, UART_NR);
 #else

Signature · 4 lines

Thanks & Regards,
Kamalesh Babulal,
Linux Technology Center,
IBM, ISTL.