From: Piet Delaney <piet.delaney@tensilica.com>
To: linux-mm@kvack.org
Cc: Piet Delaney <piet.delaney@tensilica.com>
Subject: Initialization of init_pid_ns.pid_cachep->nodelists[]
Date: Wed, 22 Oct 2008 01:36:38 -0700 [thread overview]
Message-ID: <48FEE616.6050603@tensilica.com> (raw)
I'm working on a 2.6.24 kernel with SPINLOCK debug enabled I ran into a
NULL pointer in nit_pid_ns.pid_cachep->nodelists[].
Problem occurs while creating the pid cache:
#0 panic (fmt=0xd01fd500 "kmem_list3 ==
NU"...) at
/export/src/xtensa-2.6.24-smp/kernel/panic.c:77
#1 do_tune_cpucache (cachep=0xd3803f00, limit=0x20,
batchcount=0x10, shared=0x8) at
/export/src/xtensa-2.6.24-smp/mm/slab.c:3962
#2 enable_cpucache
(cachep=0xd3803f00)
at /export/src/xtensa-2.6.24-smp/mm/slab.c:4022
#3 setup_cpu_cache
(cachep=0xd3803f00)
at /export/src/xtensa-2.6.24-smp/mm/slab.c:2088
#4 kmem_cache_create (name=0xd38054b4 "pid_1", size=0x48,
align=0x8, flags=0x12c00, ctor=0) at
/export/src/xtensa-2.6.24-smp/mm/slab.c:2401
#5 create_pid_cachep
(nr_ids=0x1)
at /export/src/xtensa-2.6.24-smp/kernel/pid.c:520
#6 pidmap_init
()
at /export/src/xtensa-2.6.24-smp/kernel/pid.c:696
#7 start_kernel
()
at /export/src/xtensa-2.6.24-smp/init/main.c:616
#8 _startup
()
at /export/src/xtensa-2.6.24-smp/arch/xtensa/kernel/head.S:250
It appears that a kmem_cache is initialized in
set_up_list3s() to point to initkmem_list3[].
init_list() to a newly allocated list
Looks like setup_cpu_cache() above #3 didn't call set_up_list3s() due to
g_cpucache_up being set to FULL. g_cpucache_up is set to FULL in
kmem_cache_init()
which was called from start_kernel() much earlier that the call to
pidmap_init().
How was nodelist to this newly created kmem_cache for pids
suppose to have been initialized by the time it gets here?
-piet
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reply other threads:[~2008-10-22 8:36 UTC|newest]
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