> > What happens with the not-even-compile-tested debug patch below?
>
> I am puzzled by this. I applied it to my slightly changed kernel with a
> lot of kernel debugging options turned on, started getting crashes on
> startup from slab.c during __kmem_cache_create. Reworked the patch,
> still the same. Commented it all out (just vmalloc->kmalloc change that
> worked fine before), still getting it.
Found it - I had disabled kobject debugging because it did not find
anything and enabled slab debugging:
-# CONFIG_DEBUG_SLAB is not set
+CONFIG_DEBUG_SLAB=y
+CONFIG_DEBUG_SLAB_LEAK=y
Reverting this config change makesit boot again so I can test it
tomorrow. But why slab fails is interesting...
>
> Sorting __ex_table...
> Memory: 493968K/523456K available (3521K kernel code, 343K rwdata, 1176K rodata, 264K init, 9803K bss, 29488K reserved)
> kernel BUG at mm/slab.c:2391!
> \|/ ____ \|/
> "@'/ .. \`@"
> /_| \__/ |_\
> \__U_/
> swapper(0): Kernel bad sw trap 5 [#1]
> CPU: 0 PID: 0 Comm: swapper Not tainted 3.11.0-rc2-00058-g20bafb3-dirty #122
> task: 00000000008ac468 ti: 000000000089c000 task.ti: 000000000089c000
> TSTATE: 0000004480e01606 TPC: 00000000004f57d4 TNPC: 00000000004f57d8 Y: 00000000 Not tainted
> TPC: <__kmem_cache_create+0x374/0x480>
> g0: 00000000000000f8 g1: 00000000008bb400 g2: 000000000002780b g3: 00000000008b5120
> g4: 00000000008ac468 g5: 0000000000000000 g6: 000000000089c000 g7: 0000000000000000
> o0: 0000000000845f08 o1: 0000000000000957 o2: ffffffffffffffe0 o3: 0000000000000000
> o4: 0000000000002004 o5: 0000000000000000 sp: 000000000089f301 ret_pc: 00000000004f57cc
> RPC: <__kmem_cache_create+0x36c/0x480>
> l0: fffff8001e812040 l1: fffff8001e819f80 l2: fffff8001e819fb8 l3: fffff8001e819fd8
> l4: 0000000000000001 l5: fffff8001e819fc8 l6: 0000000000845f08 l7: fffff8001e8300a0
> i0: fffff8001e831fa0 i1: 0000000080002800 i2: 0000000080000000 i3: 0000000000000034
> i4: 0000000000000000 i5: 0000000000002000 i6: 000000000089f3b1 i7: 0000000000907464
> I7: <create_boot_cache+0x4c/0x84>
> Call Trace:
> [0000000000907464] create_boot_cache+0x4c/0x84
> [00000000009074d0] create_kmalloc_cache+0x34/0x60
> [0000000000907540] create_kmalloc_caches+0x44/0x168
> [0000000000908dfc] kmem_cache_init+0x1d0/0x1e0
> [00000000008fc658] start_kernel+0x18c/0x370
> [0000000000761df4] tlb_fixup_done+0x88/0x94
> [0000000000000000] (null)
> Disabling lock debugging due to kernel taint
> Caller[0000000000907464]: create_boot_cache+0x4c/0x84
> Caller[00000000009074d0]: create_kmalloc_cache+0x34/0x60
> Caller[0000000000907540]: create_kmalloc_caches+0x44/0x168
> Caller[0000000000908dfc]: kmem_cache_init+0x1d0/0x1e0
> Caller[00000000008fc658]: start_kernel+0x18c/0x370
> Caller[0000000000761df4]: tlb_fixup_done+0x88/0x94
> Caller[0000000000000000]: (null)
> Instruction DUMP: 92102957 7ffccb35 90122308 <91d02005> 90100018
> 4009b371 920f20d0 ba922000 02480006
> Kernel panic - not syncing: Attempted to kill the idle task!
> Press Stop-A (L1-A) to return to the boot prom
>
>
> >
> > --->%---
> > Subject: [PATCH] Debug instrumentation of exit_openprom_fs()
> >
> >
> > Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
> > ---
> > fs/openpromfs/inode.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/fs/openpromfs/inode.c b/fs/openpromfs/inode.c
> > index 8c0ceb8..9fc4c86 100644
> > --- a/fs/openpromfs/inode.c
> > +++ b/fs/openpromfs/inode.c
> > @@ -12,12 +12,15 @@
> > #include <linux/slab.h>
> > #include <linux/seq_file.h>
> > #include <linux/magic.h>
> > +#include <linux/printk.h>
> >
> > #include <asm/openprom.h>
> > #include <asm/oplib.h>
> > #include <asm/prom.h>
> > #include <asm/uaccess.h>
> >
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > +
> > static DEFINE_MUTEX(op_mutex);
> >
> > #define OPENPROM_ROOT_INO 0
> > @@ -456,6 +459,8 @@ static int __init init_openprom_fs(void)
> >
> > static void __exit exit_openprom_fs(void)
> > {
> > + pr_info("exiting\n");
> > +
> > unregister_filesystem(&openprom_fs_type);
> > /*
> > * Make sure all delayed rcu free inodes are flushed before we
> > @@ -463,6 +468,8 @@ static void __exit exit_openprom_fs(void)
> > */
> > rcu_barrier();
> > kmem_cache_destroy(op_inode_cachep);
> > +
> > + pr_info("exited\n");
> > }
> >
> > module_init(init_openprom_fs)
> >
>
>
--
Meelis Roos (mroos@xxxxx) http://www.cs.ut.ee/~mroos/
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