Hi Alan,
Today's linux-next on a pSeries PowerPC machine panics during boot like
this:
calling .serial8250_init+0x0/0x230 @ 1
Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
------------[ cut here ]------------
kernel BUG at arch/powerpc/lib/locks.c:36!
cpu 0x0: Vector: 700 (Program Check) at [c0000000be683740]
pc: c000000000039460: .__spin_yield+0x40/0x90
lr: c000000000570284: ._spin_lock+0x84/0x90
sp: c0000000be6839c0
msr: 8000000000029032
current = 0xc0000000be67e000
paca = 0xc000000000947200
pid = 1, comm = swapper
kernel BUG at arch/powerpc/lib/locks.c:36!
enter ? for help
[c0000000be683a30] c000000000570284 ._spin_lock+0x84/0x90
[c0000000be683ab0] c00000000056e75c .__mutex_lock_slowpath+0xec/0x2d0
[c0000000be683b90] c00000000056e274 .mutex_lock+0x54/0x60
[c0000000be683c10] c00000000032f6f8 .uart_add_one_port+0xd8/0x3f0
[c0000000be683d30] c0000000007a48c4 .serial8250_init+0x1a4/0x230
[c0000000be683de0] c00000000000947c .do_one_initcall+0x6c/0x1e0
[c0000000be683ee0] c000000000779d6c .kernel_init+0x23c/0x2c0
[c0000000be683f90] c00000000002a8e4 .kernel_thread+0x54/0x70
arch/powerpc/lib/locks.c line 36 is:
lock_value = lock->slock;
if (lock_value == 0)
return;
holder_cpu = lock_value & 0xffff;
BUG_ON(holder_cpu >= NR_CPUS);
this last line. Which would imply that the lock has probably not been
initialised. Indeed, uart_add_one_port does:
struct tty_port *port;
mutex_lock(&port->mutex);
without assigning to port. See "serial-move-mutex" from the ttydev tree.
--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
http://www.canb.auug.org.au/~sfr/
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